commit

ast.go

@@ -5,9 +5,16 @@
 package expr
 
 import (
+	"errors"
 	"strings"
 )
 
+type Expr interface {
+	Eval(ctx ExprContext) (result any, err error)
+	eval(ctx ExprContext, preset bool) (result any, err error)
+	String() string
+}
+
 //-------- ast
 
 type ast struct {
@@ -19,71 +26,66 @@ func NewAst() *ast {
 	return &ast{}
 }
 
-func (expr *ast) TypeName() string {
+func (self *ast) ToForest() {
-	return "Expression"
+	if self.root != nil {
-}
+		if self.forest == nil {
-
+			self.forest = make([]*term, 0)
-func (expr *ast) ToForest() {
-	if expr.root != nil {
-		if expr.forest == nil {
-			expr.forest = make([]*term, 0)
 		}
-		expr.forest = append(expr.forest, expr.root)
+		self.forest = append(self.forest, self.root)
-		expr.root = nil
+		self.root = nil
 	}
 }
 
-func (expr *ast) String() string {
+func (self *ast) String() string {
 	var sb strings.Builder
-	if expr.root == nil {
+	if self.root == nil {
 		sb.WriteString("(nil)")
 	} else {
-		expr.root.toString(&sb)
+		self.root.toString(&sb)
 	}
 	return sb.String()
 }
 
-func (expr *ast) addTokens(tokens ...*Token) (err error) {
+func (self *ast) addTokens(tokens ...*Token) (err error) {
 	for _, tk := range tokens {
-		if _, err = expr.addToken(tk); err != nil {
+		if err = self.addToken(tk); err != nil {
 			break
 		}
 	}
 	return
 }
 
-// func (expr *ast) addToken(tk *Token) (err error) {
+func (self *ast) addToken(tk *Token) (err error) {
-// 	_, err = expr.addToken2(tk)
+	_, err = self.addToken2(tk)
-// 	return
+	return
-// }
+}
 
-func (expr *ast) addToken(tk *Token) (t *term, err error) {
+func (self *ast) addToken2(tk *Token) (t *term, err error) {
-	if t = newTerm(tk); t != nil {
+	if t = newTerm(tk, nil); t != nil {
-		err = expr.addTerm(t)
+		err = self.addTerm(t)
 	} else {
-		err = tk.Errorf("unexpected token %q", tk.String())
+		err = tk.Errorf("No term constructor for token %q", tk.String())
 	}
 	return
 }
 
-func (expr *ast) addTerm(node *term) (err error) {
+func (self *ast) addTerm(node *term) (err error) {
-	if expr.root == nil {
+	if self.root == nil {
-		expr.root = node
+		self.root = node
 	} else {
-		expr.root, err = expr.insert(expr.root, node)
+		self.root, err = self.insert(self.root, node)
 	}
 	return
 }
 
-func (expr *ast) insert(tree, node *term) (root *term, err error) {
+func (self *ast) insert(tree, node *term) (root *term, err error) {
 	if tree.getPriority() < node.getPriority() {
 		root = tree
 		if tree.isComplete() {
 			var subRoot *term
 			last := tree.removeLastChild()
-			if subRoot, err = expr.insert(last, node); err == nil {
+			subRoot, err = self.insert(last, node)
 			subRoot.setParent(tree)
-			}
 		} else {
 			node.setParent(tree)
 		}
@@ -96,22 +98,28 @@ func (expr *ast) insert(tree, node *term) (root *term, err error) {
 	return
 }
 
-func (expr *ast) Finish() {
+func (self *ast) Finish() {
-	if expr.root == nil && expr.forest != nil && len(expr.forest) >= 1 {
+	if self.root == nil && self.forest != nil && len(self.forest) >= 1 {
-		expr.root = expr.forest[len(expr.forest)-1]
+		self.root = self.forest[len(self.forest)-1]
-		expr.forest = expr.forest[0 : len(expr.forest)-1]
+		self.forest = self.forest[0 : len(self.forest)-1]
 	}
 }
 
-func (expr *ast) Eval(ctx ExprContext) (result any, err error) {
+func (self *ast) Eval(ctx ExprContext) (result any, err error) {
-	expr.Finish()
+	return self.eval(ctx, true)
+}
 
-	if expr.root != nil {
+func (self *ast) eval(ctx ExprContext, preset bool) (result any, err error) {
-		// initDefaultVars(ctx)
+	self.Finish()
-		if expr.forest != nil {
+
-			for _, root := range expr.forest {
+	if self.root != nil {
+		if preset {
+			initDefaultVars(ctx)
+		}
+		if self.forest != nil {
+			for _, root := range self.forest {
 				if result, err = root.compute(ctx); err == nil {
-					ctx.UnsafeSetVar(ControlLastResult, result)
+					ctx.setVar(ControlLastResult, result)
 				} else {
 					//err = fmt.Errorf("error in expression nr %d: %v", i+1, err)
 					break
@@ -119,12 +127,10 @@ func (expr *ast) Eval(ctx ExprContext) (result any, err error) {
 			}
 		}
 		if err == nil {
-			if result, err = expr.root.compute(ctx); err == nil {
+			result, err = self.root.compute(ctx)
-				ctx.UnsafeSetVar(ControlLastResult, result)
 		}
-		}
+	} else {
-		// } else {
+		err = errors.New("empty expression")
-		// 	err = errors.New("empty expression")
 	}
 	return
 }

ast_test.go

@@ -1,7 +1,7 @@
 // Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
 // All rights reserved.
 
-// t_ast_test.go
+// ast_test.go
 package expr
 
 import (
@@ -44,10 +44,10 @@ func TestAddTokensBad(t *testing.T) {
 func TestAddUnknownTokens(t *testing.T) {
 	tk0 := NewToken(0, 0, SymPercent, "%")
 
-	wantErr := errors.New(`unexpected token "%"`)
+	wantErr := errors.New(`No term constructor for token "%"`)
 
 	tree := NewAst()
-	if _, gotErr := tree.addToken(tk0); gotErr != nil && gotErr.Error() != wantErr.Error() {
+	if gotErr := tree.addToken(tk0); gotErr != nil && gotErr.Error() != wantErr.Error() {
 		t.Errorf("err: got <%v>, want <%v>", gotErr, wantErr)
 	}
 }

bind-expr-functions.go

@@ -1,59 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// function.go
-package expr
-
-// ---- Linking with Expr functions
-type exprFunctor struct {
-	baseFunctor
-	params []ExprFuncParam
-	expr   Expr
-	defCtx ExprContext
-}
-
-func (functor *exprFunctor) GetParams() (params []ExprFuncParam) {
-	return functor.params
-}
-
-func newExprFunctor(e Expr, params []ExprFuncParam, ctx ExprContext) *exprFunctor {
-	var defCtx ExprContext
-	if ctx != nil {
-		defCtx = ctx
-	}
-	return &exprFunctor{expr: e, params: params, defCtx: defCtx}
-}
-
-func (functor *exprFunctor) TypeName() string {
-	return "ExprFunctor"
-}
-
-func (functor *exprFunctor) GetDefinitionContext() ExprContext {
-	return functor.defCtx
-}
-
-func (functor *exprFunctor) InvokeNamed(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	var missing []string
-	for _, p := range functor.params {
-		if arg, exists := args[p.Name()]; exists {
-			if funcArg, ok := arg.(Functor); ok {
-				paramSpecs := funcArg.GetParams()
-				ctx.RegisterFunc(p.Name(), funcArg, TypeAny, paramSpecs)
-			} else {
-				ctx.UnsafeSetVar(p.Name(), arg)
-			}
-		} else {
-			if missing == nil {
-				missing = make([]string, 0, 1)
-			}
-			missing = append(missing, p.Name())
-			// ctx.UnsafeSetVar(p.Name(), nil)
-		}
-	}
-	if missing != nil {
-		err = ErrMissingParams(name, missing)
-	} else {
-		result, err = functor.expr.Eval(ctx)
-	}
-	return
-}

bind-go-functions.go

@@ -1,23 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// bind-go-function.go
-package expr
-
-// ---- Linking with Go functions
-type golangFunctor struct {
-	baseFunctor
-	f FuncTemplate
-}
-
-func NewGolangFunctor(f FuncTemplate) *golangFunctor {
-	return &golangFunctor{f: f}
-}
-
-func (functor *golangFunctor) TypeName() string {
-	return "GoFunctor"
-}
-
-func (functor *golangFunctor) InvokeNamed(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	return functor.f(ctx, name, args)
-}

builtin-base.go

@@ -1,247 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// builtin-base.go
-package expr
-
-import (
-	"fmt"
-	"math"
-	"strconv"
-	"strings"
-)
-
-const (
-	ParamDenominator = "denominator"
-)
-
-func isNilFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	result = args[ParamValue] == nil
-	return
-}
-
-func isIntFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	result = IsInteger(args[ParamValue])
-	return
-}
-
-func isFloatFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	result = IsFloat(args[ParamValue])
-	return
-}
-
-func isBoolFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	result = IsBool(args[ParamValue])
-	return
-}
-
-func isStringFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	result = IsString(args[ParamValue])
-	return
-}
-
-func isFractionFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	result = IsFract(args[ParamValue])
-	return
-}
-
-func isRationalFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	result = IsRational(args[ParamValue])
-	return
-}
-
-func isListFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	result = IsList(args[ParamValue])
-	return
-}
-
-func isDictionaryFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	result = IsDict(args[ParamValue])
-	return
-}
-
-func boolFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	switch v := args[ParamValue].(type) {
-	case int64:
-		result = (v != 0)
-	case *FractionType:
-		result = v.num != 0
-	case float64:
-		result = v != 0.0
-	case bool:
-		result = v
-	case string:
-		result = len(v) > 0
-	default:
-		err = ErrCantConvert(name, v, "bool")
-	}
-	return
-}
-
-func intFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	switch v := args[ParamValue].(type) {
-	case int64:
-		result = v
-	case float64:
-		result = int64(math.Trunc(v))
-	case bool:
-		if v {
-			result = int64(1)
-		} else {
-			result = int64(0)
-		}
-	case string:
-		var i int
-		if i, err = strconv.Atoi(v); err == nil {
-			result = int64(i)
-		}
-	default:
-		err = ErrCantConvert(name, v, "int")
-	}
-	return
-}
-
-func decFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	switch v := args[ParamValue].(type) {
-	case int64:
-		result = float64(v)
-	case float64:
-		result = v
-	case bool:
-		if v {
-			result = float64(1)
-		} else {
-			result = float64(0)
-		}
-	case string:
-		var f float64
-		if f, err = strconv.ParseFloat(v, 64); err == nil {
-			result = f
-		}
-	case *FractionType:
-		result = v.toFloat()
-	default:
-		err = ErrCantConvert(name, v, "float")
-	}
-	return
-}
-
-func stringFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	switch v := args[ParamValue].(type) {
-	case int64:
-		result = strconv.FormatInt(v, 10)
-	case float64:
-		result = strconv.FormatFloat(v, 'g', -1, 64)
-	case bool:
-		if v {
-			result = "true"
-		} else {
-			result = "false"
-		}
-	case string:
-		result = v
-	case *FractionType:
-		result = v.ToString(0)
-	case Formatter:
-		result = v.ToString(0)
-	case fmt.Stringer:
-		result = v.String()
-	default:
-		err = ErrCantConvert(name, v, "string")
-	}
-	return
-}
-
-func fractFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	switch v := args[ParamValue].(type) {
-	case int64:
-		var den int64 = 1
-
-		var ok bool
-		if den, ok = args[ParamDenominator].(int64); !ok {
-			err = ErrExpectedGot(name, "integer", args[ParamDenominator])
-		} else if den == 0 {
-			err = ErrFuncDivisionByZero(name)
-		}
-
-		if err == nil {
-			result = newFraction(v, den)
-		}
-	case float64:
-		result, err = float64ToFraction(v)
-	case bool:
-		if v {
-			result = newFraction(1, 1)
-		} else {
-			result = newFraction(0, 1)
-		}
-	case string:
-		result, err = makeGeneratingFraction(v)
-	case *FractionType:
-		result = v
-	default:
-		err = ErrCantConvert(name, v, "float")
-	}
-	return
-}
-
-// func iteratorFunc(ctx ExprContext, name string, args []any) (result any, err error) {
-// 	return
-// }
-
-func evalFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	if source, ok := args[ParamSource].(string); ok {
-		var expr Expr
-
-		parser := NewParser()
-		if ctx == nil {
-			ctx = NewSimpleStore()
-		}
-
-		r := strings.NewReader(source)
-		scanner := NewScanner(r, DefaultTranslations())
-
-		if expr, err = parser.Parse(scanner); err == nil {
-			CtrlEnable(ctx, control_export_all)
-			result, err = expr.Eval(ctx)
-		}
-	} else {
-		err = ErrWrongParamType(name, ParamSource, TypeString, args[ParamSource])
-	}
-	return
-}
-
-//// import
-
-func ImportBuiltinsFuncs(ctx ExprContext) {
-	anyParams := []ExprFuncParam{
-		NewFuncParam(ParamValue),
-	}
-
-	ctx.RegisterFunc("isNil", NewGolangFunctor(isNilFunc), TypeBoolean, anyParams)
-	ctx.RegisterFunc("isInt", NewGolangFunctor(isIntFunc), TypeBoolean, anyParams)
-	ctx.RegisterFunc("isFloat", NewGolangFunctor(isFloatFunc), TypeBoolean, anyParams)
-	ctx.RegisterFunc("isBool", NewGolangFunctor(isBoolFunc), TypeBoolean, anyParams)
-	ctx.RegisterFunc("isString", NewGolangFunctor(isStringFunc), TypeBoolean, anyParams)
-	ctx.RegisterFunc("isFract", NewGolangFunctor(isFractionFunc), TypeBoolean, anyParams)
-	ctx.RegisterFunc("isRational", NewGolangFunctor(isRationalFunc), TypeBoolean, anyParams)
-	ctx.RegisterFunc("isList", NewGolangFunctor(isListFunc), TypeBoolean, anyParams)
-	ctx.RegisterFunc("isDict", NewGolangFunctor(isDictionaryFunc), TypeBoolean, anyParams)
-
-	ctx.RegisterFunc("bool", NewGolangFunctor(boolFunc), TypeBoolean, anyParams)
-	ctx.RegisterFunc("int", NewGolangFunctor(intFunc), TypeInt, anyParams)
-	ctx.RegisterFunc("dec", NewGolangFunctor(decFunc), TypeFloat, anyParams)
-	ctx.RegisterFunc("string", NewGolangFunctor(stringFunc), TypeString, anyParams)
-	ctx.RegisterFunc("fract", NewGolangFunctor(fractFunc), TypeFraction, []ExprFuncParam{
-		NewFuncParam(ParamValue),
-		NewFuncParamFlagDef(ParamDenominator, PfDefault, int64(1)),
-	})
-
-	ctx.RegisterFunc("eval", NewGolangFunctor(evalFunc), TypeAny, []ExprFuncParam{
-		NewFuncParam(ParamSource),
-	})
-}
-
-func init() {
-	RegisterBuiltinModule("base", ImportBuiltinsFuncs, "Base expression tools like isNil(), int(), etc.")
-}

builtin-fmt.go

@@ -1,57 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// builtin-fmt.go
-package expr
-
-import (
-	"fmt"
-	"io"
-	"os"
-)
-
-func getStdout(ctx ExprContext) io.Writer {
-	var w io.Writer
-	if wany, exists := ctx.GetVar(ControlStdout); exists && wany != nil {
-		w, _ = wany.(io.Writer)
-	}
-	if w == nil {
-		w = os.Stdout
-	}
-	return w
-}
-
-func printFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	var n int = 0
-	if v, exists := args[ParamItem]; exists && v != nil {
-		argv := v.([]any)
-		n, err = fmt.Fprint(getStdout(ctx), argv...)
-	}
-	result = int64(n)
-	return
-}
-
-func printLnFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	var n int = 0
-	if v, exists := args[ParamItem]; exists && v != nil {
-		argv := v.([]any)
-		n, err = fmt.Fprintln(getStdout(ctx), argv...)
-	} else {
-		n, err = fmt.Fprintln(getStdout(ctx))
-	}
-	result = int64(n)
-	return
-}
-
-func ImportFmtFuncs(ctx ExprContext) {
-	ctx.RegisterFunc("print", NewGolangFunctor(printFunc), TypeInt, []ExprFuncParam{
-		NewFuncParamFlag(ParamItem, PfRepeat),
-	})
-	ctx.RegisterFunc("println", NewGolangFunctor(printLnFunc), TypeInt, []ExprFuncParam{
-		NewFuncParamFlag(ParamItem, PfRepeat),
-	})
-}
-
-func init() {
-	RegisterBuiltinModule("fmt", ImportFmtFuncs, "String and console formatting functions")
-}

builtin-import.go

@@ -1,78 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// builtin-import.go
-package expr
-
-import (
-	"io"
-	"os"
-)
-
-func importFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	return importGeneral(ctx, name, args)
-}
-
-func importAllFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	CtrlEnable(ctx, control_export_all)
-	return importGeneral(ctx, name, args)
-}
-
-func importGeneral(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	dirList := buildSearchDirList("sources", ENV_EXPR_SOURCE_PATH)
-	if v, exists := args[ParamFilepath]; exists && v != nil {
-		argv := v.([]any)
-		result, err = doImport(ctx, name, dirList, NewArrayIterator(argv))
-	}
-	return
-}
-
-func doImport(ctx ExprContext, name string, dirList []string, it Iterator) (result any, err error) {
-	var v any
-	var sourceFilepath string
-
-	for v, err = it.Next(); err == nil; v, err = it.Next() {
-		if err = checkStringParamExpected(name, v, it.Index()); err != nil {
-			break
-		}
-		if sourceFilepath, err = makeFilepath(v.(string), dirList); err != nil {
-			break
-		}
-		var file *os.File
-		if file, err = os.Open(sourceFilepath); err == nil {
-			defer file.Close()
-			var expr *ast
-			scanner := NewScanner(file, DefaultTranslations())
-			parser := NewParser()
-			if expr, err = parser.parseGeneral(scanner, allowMultiExpr|allowVarRef, SymEos); err == nil {
-				result, err = expr.Eval(ctx)
-			}
-			if err != nil {
-				break
-			}
-		} else {
-			break
-		}
-	}
-	if err != nil {
-		if err == io.EOF {
-			err = nil
-		} else {
-			result = nil
-		}
-	}
-	return
-}
-
-func ImportImportFuncs(ctx ExprContext) {
-	ctx.RegisterFunc("import", NewGolangFunctor(importFunc), TypeAny, []ExprFuncParam{
-		NewFuncParamFlag(ParamFilepath, PfRepeat),
-	})
-	ctx.RegisterFunc("importAll", NewGolangFunctor(importAllFunc), TypeAny, []ExprFuncParam{
-		NewFuncParamFlag(ParamFilepath, PfRepeat),
-	})
-}
-
-func init() {
-	RegisterBuiltinModule("import", ImportImportFuncs, "Functions import() and include()")
-}

builtin-iterator.go

@@ -1,104 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// builtin-iterator.go
-package expr
-
-import (
-	"fmt"
-	"io"
-)
-
-const (
-	iterParamOperator = "operator"
-	iterParamVars     = "vars"
-	iterVarStatus     = "status"
-)
-
-func parseRunArgs(localCtx ExprContext, args map[string]any) (it Iterator, op Functor, err error) {
-	var ok bool
-
-	if it, ok = args[ParamIterator].(Iterator); !ok {
-		err = fmt.Errorf("paramter %q must be an iterator, passed %v [%s]", ParamIterator, args[ParamIterator], TypeName(args[ParamIterator]))
-		return
-	}
-
-	if op, ok = args[iterParamOperator].(Functor); !ok && args[iterParamOperator] != nil {
-		err = fmt.Errorf("paramter %q must be a function, passed %v [%s]", iterParamOperator, args[iterParamOperator], TypeName(args[iterParamOperator]))
-		return
-	}
-
-	var vars *DictType
-	if vars, ok = args[iterParamVars].(*DictType); !ok && args[iterParamVars] != nil {
-		err = fmt.Errorf("paramter %q must be a dictionary, passed %v [%s]", iterParamVars, args[iterParamVars], TypeName(args[iterParamVars]))
-		return
-	}
-
-	if vars != nil {
-		for key, value := range *vars {
-			var varName string
-			if varName, ok = key.(string); ok {
-				localCtx.UnsafeSetVar(varName, value)
-			}
-		}
-	}
-
-	return
-}
-
-func runFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	var it Iterator
-	var ok bool
-	var op Functor
-	var v any
-	var usingDefaultOp = false
-	var params map[string]any
-	var item any
-
-	localCtx := ctx.Clone()
-	localCtx.UnsafeSetVar(iterVarStatus, nil)
-
-	if it, op, err = parseRunArgs(localCtx, args); err != nil {
-		return
-	} else if op == nil {
-		op = NewGolangFunctor(printLnFunc)
-		usingDefaultOp = true
-	}
-
-	for item, err = it.Next(); err == nil; item, err = it.Next() {
-		if usingDefaultOp {
-			params = map[string]any{ParamItem: []any{item}}
-		} else {
-			params = map[string]any{ParamIndex: it.Index(), ParamItem: item}
-		}
-
-		if v, err = op.InvokeNamed(localCtx, iterParamOperator, params); err != nil {
-			break
-		} else {
-			var success bool
-			if success, ok = ToBool(v); !success || !ok {
-				break
-			}
-		}
-	}
-
-	if err == io.EOF {
-		err = nil
-	}
-	if err == nil {
-		result, _ = localCtx.GetVar(iterVarStatus)
-	}
-	return
-}
-
-func ImportIterFuncs(ctx ExprContext) {
-	ctx.RegisterFunc("run", NewGolangFunctor(runFunc), TypeAny, []ExprFuncParam{
-		NewFuncParam(ParamIterator),
-		NewFuncParamFlag(iterParamOperator, PfOptional),
-		NewFuncParamFlag(iterParamVars, PfOptional),
-	})
-}
-
-func init() {
-	RegisterBuiltinModule("iterator", ImportIterFuncs, "Iterator helper functions")
-}

builtin-math-arith.go

@@ -1,183 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// builtin-math-arith.go
-package expr
-
-import (
-	"fmt"
-	"io"
-)
-
-func checkNumberParamExpected(funcName string, paramValue any, paramPos, level, subPos int) (err error) {
-	if !(IsNumber(paramValue) || isFraction(paramValue)) /*|| isList(paramValue)*/ {
-		err = fmt.Errorf("%s(): param nr %d (%d in %d) has wrong type %T, number expected",
-			funcName, paramPos+1, subPos+1, level, paramValue)
-	}
-	return
-}
-
-func doAdd(ctx ExprContext, name string, it Iterator, count, level int) (result any, err error) {
-	var sumAsFloat, sumAsFract bool
-	var floatSum float64 = 0.0
-	var intSum int64 = 0
-	var fractSum *FractionType
-	var v any
-
-	level++
-
-	for v, err = it.Next(); err == nil; v, err = it.Next() {
-		if list, ok := v.(*ListType); ok {
-			v = NewListIterator(list, nil)
-		}
-		if subIter, ok := v.(Iterator); ok {
-			if v, err = doAdd(ctx, name, subIter, count, level); err != nil {
-				break
-			}
-			if extIter, ok := v.(ExtIterator); ok && extIter.HasOperation(CleanName) {
-				if _, err = extIter.CallOperation(CleanName, nil); err != nil {
-					return
-				}
-			}
-		} else if err = checkNumberParamExpected(name, v, count, level, it.Index()); err != nil {
-			break
-		}
-		count++
-
-		if !sumAsFloat {
-			if IsFloat(v) {
-				sumAsFloat = true
-				if sumAsFract {
-					floatSum = fractSum.toFloat()
-				} else {
-					floatSum = float64(intSum)
-				}
-			} else if !sumAsFract && isFraction(v) {
-				fractSum = newFraction(intSum, 1)
-				sumAsFract = true
-			}
-		}
-
-		if sumAsFloat {
-			floatSum += numAsFloat(v)
-		} else if sumAsFract {
-			var item *FractionType
-			var ok bool
-			if item, ok = v.(*FractionType); !ok {
-				iv, _ := v.(int64)
-				item = newFraction(iv, 1)
-			}
-			fractSum = sumFract(fractSum, item)
-		} else {
-			iv, _ := v.(int64)
-			intSum += iv
-		}
-	}
-	if err == nil || err == io.EOF {
-		err = nil
-		if sumAsFloat {
-			result = floatSum
-		} else if sumAsFract {
-			result = fractSum
-		} else {
-			result = intSum
-		}
-	}
-	return
-}
-
-func addFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	argv := args[ParamValue].([]any)
-	result, err = doAdd(ctx, name, NewArrayIterator(argv), 0, -1)
-	return
-}
-
-func doMul(ctx ExprContext, name string, it Iterator, count, level int) (result any, err error) {
-	var mulAsFloat, mulAsFract bool
-	var floatProd float64 = 1.0
-	var intProd int64 = 1
-	var fractProd *FractionType
-	var v any
-
-	level++
-	for v, err = it.Next(); err == nil; v, err = it.Next() {
-		if list, ok := v.(*ListType); ok {
-			v = NewListIterator(list, nil)
-		}
-		if subIter, ok := v.(Iterator); ok {
-			if v, err = doMul(ctx, name, subIter, count, level); err != nil {
-				break
-			}
-			if extIter, ok := v.(ExtIterator); ok && extIter.HasOperation(CleanName) {
-				if _, err = extIter.CallOperation(CleanName, nil); err != nil {
-					return
-				}
-			}
-		} else {
-			if err = checkNumberParamExpected(name, v, count, level, it.Index()); err != nil {
-				break
-			}
-		}
-		count++
-
-		if !mulAsFloat {
-			if IsFloat(v) {
-				mulAsFloat = true
-				if mulAsFract {
-					floatProd = fractProd.toFloat()
-				} else {
-					floatProd = float64(intProd)
-				}
-			} else if !mulAsFract && isFraction(v) {
-				fractProd = newFraction(intProd, 1)
-				mulAsFract = true
-			}
-		}
-
-		if mulAsFloat {
-			floatProd *= numAsFloat(v)
-		} else if mulAsFract {
-			var item *FractionType
-			var ok bool
-			if item, ok = v.(*FractionType); !ok {
-				iv, _ := v.(int64)
-				item = newFraction(iv, 1)
-			}
-			fractProd = mulFract(fractProd, item)
-		} else {
-			iv, _ := v.(int64)
-			intProd *= iv
-		}
-	}
-	if err == nil || err == io.EOF {
-		err = nil
-		if mulAsFloat {
-			result = floatProd
-		} else if mulAsFract {
-			result = fractProd
-		} else {
-			result = intProd
-		}
-	}
-	return
-}
-
-func mulFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	argv := args[ParamValue].([]any)
-	result, err = doMul(ctx, name, NewArrayIterator(argv), 0, -1)
-	return
-}
-
-func ImportMathFuncs(ctx ExprContext) {
-	ctx.RegisterFunc("add", NewGolangFunctor(addFunc), TypeNumber, []ExprFuncParam{
-		NewFuncParamFlagDef(ParamValue, PfDefault|PfRepeat, int64(0)),
-	})
-
-	ctx.RegisterFunc("mul", NewGolangFunctor(mulFunc), TypeNumber, []ExprFuncParam{
-		NewFuncParamFlagDef(ParamValue, PfDefault|PfRepeat, int64(1)),
-	})
-}
-
-func init() {
-	RegisterBuiltinModule("math.arith", ImportMathFuncs, "Functions add() and mul()")
-}

builtin-os-file.go

@@ -1,257 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// builtin-os-file.go
-package expr
-
-import (
-	"bufio"
-	"fmt"
-	"io"
-	"os"
-)
-
-const (
-	osLimitCh = "limitCh"
-)
-
-type osHandle interface {
-	getFile() *os.File
-}
-
-type osWriter struct {
-	fh     *os.File
-	writer *bufio.Writer
-}
-
-func (h *osWriter) TypeName() string {
-	return "osWriter"
-}
-
-func (h *osWriter) String() string {
-	return "writer"
-}
-
-func (h *osWriter) getFile() *os.File {
-	return h.fh
-}
-
-type osReader struct {
-	fh     *os.File
-	reader *bufio.Reader
-}
-
-func (h *osReader) TypeName() string {
-	return "osReader"
-}
-
-func (h *osReader) String() string {
-	return "reader"
-}
-
-func (h *osReader) getFile() *os.File {
-	return h.fh
-}
-
-func errMissingFilePath(funcName string) error {
-	return fmt.Errorf("%s(): missing or invalid file path", funcName)
-}
-
-func errInvalidFileHandle(funcName string, v any) error {
-	if v != nil {
-		return fmt.Errorf("%s(): invalid file handle %v [%T]", funcName, v, v)
-	} else {
-		return fmt.Errorf("%s(): invalid file handle", funcName)
-	}
-}
-
-func createFileFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	if filePath, ok := args[ParamFilepath].(string); ok && len(filePath) > 0 {
-		var fh *os.File
-		if fh, err = os.Create(filePath); err == nil {
-			result = &osWriter{fh: fh, writer: bufio.NewWriter(fh)}
-		}
-	} else {
-		err = errMissingFilePath(name)
-	}
-	return
-}
-
-func openFileFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	if filePath, ok := args[ParamFilepath].(string); ok && len(filePath) > 0 {
-		var fh *os.File
-		if fh, err = os.Open(filePath); err == nil {
-			result = &osReader{fh: fh, reader: bufio.NewReader(fh)}
-		}
-	} else {
-		err = errMissingFilePath(name)
-	}
-	return
-}
-
-func appendFileFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	if filePath, ok := args[ParamFilepath].(string); ok && len(filePath) > 0 {
-		var fh *os.File
-		if fh, err = os.OpenFile(filePath, os.O_APPEND|os.O_WRONLY|os.O_CREATE, 0660); err == nil {
-			result = &osWriter{fh: fh, writer: bufio.NewWriter(fh)}
-		}
-	} else {
-		err = errMissingFilePath(name)
-	}
-	return
-}
-
-func closeFileFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	var handle osHandle
-	var invalidFileHandle any
-	var ok bool
-
-	if handle, ok = args[ParamHandle].(osHandle); !ok {
-		invalidFileHandle = args[ParamHandle]
-	}
-
-	if handle != nil {
-		if fh := handle.getFile(); fh != nil {
-			if w, ok := handle.(*osWriter); ok {
-				err = w.writer.Flush()
-			}
-
-			if err == nil {
-				err = fh.Close()
-			}
-		}
-	}
-	if err == nil && (handle == nil || invalidFileHandle != nil) {
-		err = errInvalidFileHandle(name, handle)
-	}
-	result = err == nil
-	return
-}
-
-func fileWriteTextFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	var handle osHandle
-	var invalidFileHandle any
-	var ok bool
-
-	if handle, ok = args[ParamHandle].(osHandle); !ok {
-		invalidFileHandle = args[ParamHandle]
-	}
-
-	if handle != nil {
-		if w, ok := handle.(*osWriter); ok {
-			if v, exists := args[ParamItem]; exists {
-				argv := v.([]any)
-				result, err = fmt.Fprint(w.writer, argv...)
-			}
-		} else {
-			invalidFileHandle = handle
-		}
-	}
-
-	if err == nil && (handle == nil || invalidFileHandle != nil) {
-		err = errInvalidFileHandle(name, invalidFileHandle)
-	}
-	return
-}
-
-func fileReadTextFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	var handle osHandle
-	var invalidFileHandle any
-	var ok bool
-
-	result = nil
-	if handle, ok = args[ParamHandle].(osHandle); !ok || args[ParamHandle] == nil {
-		invalidFileHandle = args[ParamHandle]
-	}
-
-	if handle != nil {
-		if r, ok := handle.(*osReader); ok {
-			var limit byte = '\n'
-			var v string
-			if s, ok := args[osLimitCh].(string); ok && len(s) > 0 {
-				limit = s[0]
-			}
-
-			v, err = r.reader.ReadString(limit)
-			if err == io.EOF {
-				err = nil
-			}
-			if len(v) > 0 {
-				if v[len(v)-1] == limit {
-					result = v[0 : len(v)-1]
-				} else {
-					result = v
-				}
-			}
-		} else {
-			invalidFileHandle = handle
-		}
-	}
-
-	if err == nil && (handle == nil || invalidFileHandle != nil) {
-		err = errInvalidFileHandle(name, invalidFileHandle)
-	}
-	return
-}
-
-func fileReadTextAllFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	var handle osHandle
-	var invalidFileHandle any
-	var ok bool
-
-	result = nil
-	if handle, ok = args[ParamHandle].(osHandle); !ok || args[ParamHandle] == nil {
-		invalidFileHandle = args[ParamHandle]
-	}
-
-	if handle != nil {
-		if r, ok := handle.(*osReader); ok {
-			var b []byte
-			b, err = io.ReadAll(r.reader)
-			result = string(b)
-		} else {
-			invalidFileHandle = handle
-		}
-	}
-
-	if err == nil && (handle == nil || invalidFileHandle != nil) {
-		err = errInvalidFileHandle(name, invalidFileHandle)
-	}
-	return
-}
-
-func ImportOsFuncs(ctx ExprContext) {
-	ctx.RegisterFunc("fileOpen", NewGolangFunctor(openFileFunc), TypeFileHandle, []ExprFuncParam{
-		NewFuncParam(ParamFilepath),
-	})
-
-	ctx.RegisterFunc("fileAppend", NewGolangFunctor(appendFileFunc), TypeFileHandle, []ExprFuncParam{
-		NewFuncParam(ParamFilepath),
-	})
-
-	ctx.RegisterFunc("fileCreate", NewGolangFunctor(createFileFunc), TypeFileHandle, []ExprFuncParam{
-		NewFuncParam(ParamFilepath),
-	})
-
-	ctx.RegisterFunc("fileClose", NewGolangFunctor(closeFileFunc), TypeBoolean, []ExprFuncParam{
-		NewFuncParam(ParamHandle),
-	})
-
-	ctx.RegisterFunc("fileWriteText", NewGolangFunctor(fileWriteTextFunc), TypeInt, []ExprFuncParam{
-		NewFuncParam(ParamHandle),
-		NewFuncParamFlagDef(ParamItem, PfDefault|PfRepeat, ""),
-	})
-
-	ctx.RegisterFunc("fileReadText", NewGolangFunctor(fileReadTextFunc), TypeString, []ExprFuncParam{
-		NewFuncParam(ParamHandle),
-		NewFuncParamFlagDef(osLimitCh, PfDefault, "\n"),
-	})
-
-	ctx.RegisterFunc("fileReadTextAll", NewGolangFunctor(fileReadTextAllFunc), TypeString, []ExprFuncParam{
-		NewFuncParam(ParamHandle),
-	})
-}
-
-func init() {
-	RegisterBuiltinModule("os.file", ImportOsFuncs, "Operating system file functions")
-}

builtin-string.go

@@ -1,245 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// builtin-string.go
-package expr
-
-import (
-	"fmt"
-	"io"
-	"strings"
-)
-
-const (
-	strParamOther = "other"
-)
-
-// --- Start of function definitions
-func doJoinStr(funcName string, sep string, it Iterator) (result any, err error) {
-	var sb strings.Builder
-	var v any
-	for v, err = it.Next(); err == nil; v, err = it.Next() {
-		if it.Index() > 0 {
-			sb.WriteString(sep)
-		}
-		if s, ok := v.(string); ok {
-			sb.WriteString(s)
-		} else {
-			err = ErrExpectedGot(funcName, TypeString, v)
-			return
-		}
-	}
-	if err == io.EOF {
-		err = nil
-		result = sb.String()
-	}
-	return
-}
-
-func joinStrFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	if sep, ok := args[ParamSeparator].(string); ok {
-		if v, exists := args[ParamItem]; exists {
-			argv := v.([]any)
-			if len(argv) == 1 {
-				if ls, ok := argv[0].(*ListType); ok {
-					result, err = doJoinStr(name, sep, NewListIterator(ls, nil))
-				} else if it, ok := argv[0].(Iterator); ok {
-					result, err = doJoinStr(name, sep, it)
-				} else if s, ok := argv[0].(string); ok {
-					result = s
-				} else {
-					err = ErrInvalidParameterValue(name, ParamItem, v)
-				}
-			} else {
-				result, err = doJoinStr(name, sep, NewArrayIterator(argv))
-			}
-		}
-	} else {
-		err = ErrWrongParamType(name, ParamSeparator, TypeString, args[ParamSeparator])
-	}
-	return
-}
-
-func subStrFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	var start = 0
-	var count = -1
-	var source string
-	var ok bool
-
-	if source, ok = args[ParamSource].(string); !ok {
-		return nil, ErrWrongParamType(name, ParamSource, TypeString, args[ParamSource])
-	}
-
-	if start, err = ToGoInt(args[ParamStart], name+"()"); err != nil {
-		return
-	}
-
-	if count, err = ToGoInt(args[ParamCount], name+"()"); err != nil {
-		return
-	}
-
-	if start < 0 {
-		start = len(source) + start
-	}
-
-	if count < 0 {
-		count = len(source) - start
-	}
-	end := min(start+count, len(source))
-	result = source[start:end]
-	return
-}
-
-func trimStrFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	var source string
-	var ok bool
-
-	if source, ok = args[ParamSource].(string); !ok {
-		return nil, ErrWrongParamType(name, ParamSource, TypeString, args[ParamSource])
-	}
-	result = strings.TrimSpace(source)
-	return
-}
-
-func startsWithStrFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	var source, prefix string
-	var ok bool
-
-	result = false
-
-	if source, ok = args[ParamSource].(string); !ok {
-		return result, ErrWrongParamType(name, ParamSource, TypeString, args[ParamSource])
-	}
-
-	if prefix, ok = args[ParamPrefix].(string); !ok {
-		return result, ErrWrongParamType(name, ParamPrefix, TypeString, args[ParamPrefix])
-	}
-	if strings.HasPrefix(source, prefix) {
-		result = true
-	} else if v, exists := args[strParamOther]; exists {
-		argv := v.([]any)
-		for i, targetSpec := range argv {
-			if target, ok := targetSpec.(string); ok {
-				if strings.HasPrefix(source, target) {
-					result = true
-					break
-				}
-			} else {
-				err = fmt.Errorf("target item nr %d is %s, string expected", i+1, TypeName(targetSpec))
-				break
-			}
-		}
-	}
-	return
-}
-
-func endsWithStrFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	var source, suffix string
-	var ok bool
-
-	result = false
-
-	if source, ok = args[ParamSource].(string); !ok {
-		return result, ErrWrongParamType(name, ParamSource, TypeString, args[ParamSource])
-	}
-
-	if suffix, ok = args[ParamSuffix].(string); !ok {
-		return result, ErrWrongParamType(name, ParamSuffix, TypeString, args[ParamSuffix])
-	}
-	if strings.HasPrefix(source, suffix) {
-		result = true
-	} else if v, exists := args[strParamOther]; exists {
-		argv := v.([]any)
-		for i, targetSpec := range argv {
-			if target, ok := targetSpec.(string); ok {
-				if strings.HasSuffix(source, target) {
-					result = true
-					break
-				}
-			} else {
-				err = fmt.Errorf("target item nr %d is %s, string expected", i+1, TypeName(targetSpec))
-				break
-			}
-		}
-	}
-	return
-}
-
-func splitStrFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
-	var source, sep string
-	var count int = -1
-	var parts []string
-	var ok bool
-
-	if source, ok = args[ParamSource].(string); !ok {
-		return result, ErrWrongParamType(name, ParamSource, TypeString, args[ParamSource])
-	}
-
-	if sep, ok = args[ParamSeparator].(string); !ok {
-		return nil, fmt.Errorf("separator param must be string, got %s (%v)", TypeName(args[ParamSeparator]), args[ParamSeparator])
-	}
-
-	if count64, ok := args[ParamCount].(int64); ok { // TODO replace type assertion with toInt()
-		count = int(count64)
-	} else {
-		return nil, fmt.Errorf("part count must be integer, got %s (%v)", TypeName(args[ParamCount]), args[ParamCount])
-	}
-
-	if count > 0 {
-		parts = strings.SplitN(source, sep, count)
-	} else if count < 0 {
-		parts = strings.Split(source, sep)
-	} else {
-		parts = []string{}
-	}
-	list := make(ListType, len(parts))
-	for i, part := range parts {
-		list[i] = part
-	}
-	result = &list
-	return
-}
-
-// --- End of function definitions
-
-// Import above functions in the context
-func ImportStringFuncs(ctx ExprContext) {
-	ctx.RegisterFunc("strJoin", NewGolangFunctor(joinStrFunc), TypeString, []ExprFuncParam{
-		NewFuncParam(ParamSeparator),
-		NewFuncParamFlag(ParamItem, PfRepeat),
-	})
-
-	ctx.RegisterFunc("strSub", NewGolangFunctor(subStrFunc), TypeString, []ExprFuncParam{
-		NewFuncParam(ParamSource),
-		NewFuncParamFlagDef(ParamStart, PfDefault, int64(0)),
-		NewFuncParamFlagDef(ParamCount, PfDefault, int64(-1)),
-	})
-
-	ctx.RegisterFunc("strSplit", NewGolangFunctor(splitStrFunc), "list of "+TypeString, []ExprFuncParam{
-		NewFuncParam(ParamSource),
-		NewFuncParamFlagDef(ParamSeparator, PfDefault, ""),
-		NewFuncParamFlagDef(ParamCount, PfDefault, int64(-1)),
-	})
-
-	ctx.RegisterFunc("strTrim", NewGolangFunctor(trimStrFunc), TypeString, []ExprFuncParam{
-		NewFuncParam(ParamSource),
-	})
-
-	ctx.RegisterFunc("strStartsWith", NewGolangFunctor(startsWithStrFunc), TypeBoolean, []ExprFuncParam{
-		NewFuncParam(ParamSource),
-		NewFuncParam(ParamPrefix),
-		NewFuncParamFlag(strParamOther, PfRepeat),
-	})
-
-	ctx.RegisterFunc("strEndsWith", NewGolangFunctor(endsWithStrFunc), TypeBoolean, []ExprFuncParam{
-		NewFuncParam(ParamSource),
-		NewFuncParam(ParamSuffix),
-		NewFuncParamFlag(strParamOther, PfRepeat),
-	})
-}
-
-// Register the import function in the import-register.
-// That will allow to import all function of this module by the "builtin" operator."
-func init() {
-	RegisterBuiltinModule("string", ImportStringFuncs, "string utilities")
-}

builtins-register.go

@@ -1,48 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// builtins-register.go
-package expr
-
-import (
-	"fmt"
-)
-
-type builtinModule struct {
-	importFunc  func(ExprContext)
-	description string
-	imported    bool
-}
-
-func newBuiltinModule(importFunc func(ExprContext), description string) *builtinModule {
-	return &builtinModule{importFunc, description, false}
-}
-
-var builtinModuleRegister map[string]*builtinModule
-
-func RegisterBuiltinModule(name string, importFunc func(ExprContext), description string) {
-	if builtinModuleRegister == nil {
-		builtinModuleRegister = make(map[string]*builtinModule)
-	}
-	if _, exists := builtinModuleRegister[name]; exists {
-		panic(fmt.Errorf("module %q already registered", name))
-	}
-	builtinModuleRegister[name] = newBuiltinModule(importFunc, description)
-}
-
-func IterateBuiltinModules(op func(name, description string, imported bool) bool) {
-	if op != nil {
-		for name, mod := range builtinModuleRegister {
-			if !op(name, mod.description, mod.imported) {
-				break
-			}
-		}
-	}
-}
-
-// ----
-func init() {
-	if builtinModuleRegister == nil {
-		builtinModuleRegister = make(map[string]*builtinModule)
-	}
-}

byte-slider.go

@@ -18,17 +18,17 @@ func NewByteSlider(size int) *ByteSlider {
 	}
 }
 
-func (slider *ByteSlider) PushEnd(b byte) {
+func (self *ByteSlider) PushEnd(b byte) {
-	if slider.length == cap(slider.buf) {
+	if self.length == cap(self.buf) {
-		slider.length--
+		self.length--
-		for i := 0; i < slider.length; i++ {
+		for i := 0; i < self.length; i++ {
-			slider.buf[i] = slider.buf[i+1]
+			self.buf[i] = self.buf[i+1]
 		}
 	}
-	slider.buf[slider.length] = b
+	self.buf[self.length] = b
-	slider.length++
+	self.length++
 }
 
-func (slider *ByteSlider) Equal(target []byte) bool {
+func (self *ByteSlider) Equal(target []byte) bool {
-	return target != nil && bytes.Equal(slider.buf, target)
+	return target != nil && bytes.Equal(self.buf, target)
 }

common-errors.go

@@ -1,87 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// common-errors.go
-package expr
-
-import (
-	"fmt"
-	"strings"
-)
-
-func ErrMissingParams(funcName string, missing []string) (err error) {
-	return fmt.Errorf("%s(): missing params -- %s", funcName, strings.Join(missing, ", "))
-}
-
-func ErrTooFewParams(funcName string, minArgs, maxArgs, argCount int) (err error) {
-	if maxArgs < 0 {
-		err = fmt.Errorf("%s(): too few params -- expected %d or more, got %d", funcName, minArgs, argCount)
-	} else {
-		err = fmt.Errorf("%s(): too few params -- expected %d, got %d", funcName, minArgs, argCount)
-	}
-	return
-}
-
-func ErrTooManyParams(funcName string, maxArgs, argCount int) (err error) {
-	err = fmt.Errorf("%s(): too many params -- expected %d, got %d", funcName, maxArgs, argCount)
-	return
-}
-
-// --- General errors
-
-func ErrCantConvert(funcName string, value any, kind string) error {
-	return fmt.Errorf("%s(): can't convert %s to %s", funcName, TypeName(value), kind)
-}
-
-func ErrExpectedGot(funcName string, kind string, value any) error {
-	return fmt.Errorf("%s(): expected %s, got %s (%v)", funcName, kind, TypeName(value), value)
-}
-
-func ErrFuncDivisionByZero(funcName string) error {
-	return fmt.Errorf("%s(): division by zero", funcName)
-}
-
-// func ErrDivisionByZero() error {
-// 	return fmt.Errorf("division by zero")
-// }
-
-// --- Parameter errors
-
-// func ErrMissingRequiredParameter(funcName, paramName string) error {
-// 	return fmt.Errorf("%s(): missing required parameter %q", funcName, paramName)
-// }
-
-func ErrInvalidParameterValue(funcName, paramName string, paramValue any) error {
-	return fmt.Errorf("%s(): invalid value %s (%v) for parameter %q", funcName, TypeName(paramValue), paramValue, paramName)
-}
-
-func undefArticle(s string) (article string) {
-	if len(s) > 0 && strings.Contains("aeiou", s[0:1]) {
-		article = "an"
-	} else {
-		article = "a"
-	}
-	return
-}
-
-func prependUndefArticle(s string) (result string) {
-	return undefArticle(s) + " " + s
-}
-
-func ErrWrongParamType(funcName, paramName, paramType string, paramValue any) error {
-	var artWantType, artGotType string
-	gotType := TypeName(paramValue)
-	artGotType = prependUndefArticle(gotType)
-	artWantType = prependUndefArticle(paramType)
-	return fmt.Errorf("%s(): the %q parameter must be %s, got %s (%v)", funcName, paramName, artWantType, artGotType, paramValue)
-}
-
-func ErrUnknownParam(funcName, paramName string) error {
-	return fmt.Errorf("%s(): unknown parameter %q", funcName, paramName)
-}
-
-// --- Operator errors
-
-func ErrLeftOperandMustBeVariable(leftTerm, opTerm *term) error {
-	return leftTerm.Errorf("left operand of %q must be a variable", opTerm.source())
-}

common-params.go

@@ -1,32 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// common-params.go
-package expr
-
-const (
-	ParamArgs      = "args"
-	ParamCount     = "count"
-	ParamItem      = "item"
-	ParamIndex     = "index"
-	ParamParts     = "parts"
-	ParamSeparator = "separator"
-	ParamSource    = "source"
-	ParamSuffix    = "suffix"
-	ParamPrefix    = "prefix"
-	ParamStart     = "start"
-	ParamEnd       = "end"
-	ParamValue     = "value"
-	ParamName      = "name"
-	ParamEllipsis  = "..."
-	ParamFilepath  = "filepath"
-	ParamDirpath   = "dirpath"
-	ParamHandle    = "handle"
-	ParamResource  = "resource"
-	ParamIterator  = "iterator"
-)
-
-// to be moved in its own source file
-const (
-	ConstLastIndex = 0xFFFF_FFFF
-)

common-type-names.go

@@ -1,22 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// common-type-names.go
-package expr
-
-const (
-	TypeAny           = "any"
-	TypeNil           = "nil"
-	TypeBoolean       = "boolean"
-	TypeFloat         = "float"
-	TypeFraction      = "fraction"
-	TypeFileHandle    = "file-handle"
-	TypeInt           = "integer"
-	TypeItem          = "item"
-	TypeNumber        = "number"
-	TypePair          = "pair"
-	TypeString        = "string"
-	TypeDict          = "dict"
-	TypeListOf        = "list-of-"
-	TypeListOfStrings = "list-of-strings"
-)

context-helpers.go

@@ -1,49 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// context-helpers.go
-package expr
-
-func cloneContext(sourceCtx ExprContext) (clonedCtx ExprContext) {
-	if sourceCtx != nil {
-		clonedCtx = sourceCtx.Clone()
-	}
-	return
-}
-
-func exportVar(ctx ExprContext, name string, value any) {
-	if name[0] == '@' {
-		name = name[1:]
-	}
-	ctx.UnsafeSetVar(name, value)
-}
-
-func exportFunc(ctx ExprContext, name string, info ExprFunc) {
-	if name[0] == '@' {
-		name = name[1:]
-	}
-	ctx.RegisterFunc(name, info.Functor(), info.ReturnType(), info.Params())
-}
-
-func exportObjects(destCtx, sourceCtx ExprContext) {
-	exportAll := CtrlIsEnabled(sourceCtx, control_export_all)
-	// fmt.Printf("Exporting from sourceCtx [%p] to destCtx [%p] -- exportAll=%t\n", sourceCtx, destCtx, exportAll)
-	// Export variables
-	for _, refName := range sourceCtx.EnumVars(func(name string) bool { return (exportAll || name[0] == '@') && !(name[0] == '_') }) {
-		// fmt.Printf("\tExporting %q\n", refName)
-		refValue, _ := sourceCtx.GetVar(refName)
-		exportVar(destCtx, refName, refValue)
-	}
-	// Export functions
-	for _, refName := range sourceCtx.EnumFuncs(func(name string) bool { return exportAll || name[0] == '@' }) {
-		if info, _ := sourceCtx.GetFuncInfo(refName); info != nil {
-			exportFunc(destCtx, refName, info)
-		}
-	}
-}
-
-func exportObjectsToParent(sourceCtx ExprContext) {
-	if parentCtx := sourceCtx.GetParent(); parentCtx != nil {
-		exportObjects(parentCtx, sourceCtx)
-	}
-}

context.go

@@ -0,0 +1,42 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
+// context.go
+package expr
+
+// ---- Function template
+type FuncTemplate func(ctx ExprContext, name string, args []any) (result any, err error)
+
+// ---- Functor interface
+type Functor interface {
+	Invoke(ctx ExprContext, name string, args []any) (result any, err error)
+}
+
+type simpleFunctor struct {
+	f FuncTemplate
+}
+
+func (functor *simpleFunctor) Invoke(ctx ExprContext, name string, args []any) (result any, err error) {
+	return functor.f(ctx, name, args)
+}
+
+// ---- Function Info
+type ExprFunc interface {
+	Name() string
+	MinArgs() int
+	MaxArgs() int
+	Functor() Functor
+}
+
+// ----Expression Context
+type ExprContext interface {
+	Clone() ExprContext
+	GetVar(varName string) (value any, exists bool)
+	SetVar(varName string, value any)
+	setVar(varName string, value any)
+	EnumVars(func(name string) (accept bool)) (varNames []string)
+	EnumFuncs(func(name string) (accept bool)) (funcNames []string)
+	GetFuncInfo(name string) ExprFunc
+	Call(name string, args []any) (result any, err error)
+	RegisterFunc(name string, f Functor, minArgs, maxArgs int)
+}

control.go

@@ -4,14 +4,13 @@
 // control.go
 package expr
 
+import "strings"
+
 // Preset control variables
 const (
-	ControlPreset        = "_preset"
 	ControlLastResult   = "last"
 	ControlBoolShortcut = "_bool_shortcut"
-	ControlSearchPath    = "_search_path"
+	ControlImportPath   = "_import_path"
-	ControlParentContext = "_parent_context"
-	ControlStdout        = "_stdout"
 )
 
 // Other control variables
@@ -21,20 +20,43 @@ const (
 
 // Initial values
 const (
-	init_search_path = "~/.local/lib/go-pkg/expr:/usr/local/lib/go-pkg/expr:/usr/lib/go-pkg/expr"
+	init_import_path = "~/.local/lib/go-pkg/expr:/usr/local/lib/go-pkg/expr:/usr/lib/go-pkg/expr"
 )
 
-func SetCtrl(ctx ExprContext, name string, value any) (current any) {
+func initDefaultVars(ctx ExprContext) {
-	current, _ = ctx.GetVar(name)
+	ctx.SetVar(ControlBoolShortcut, true)
-	ctx.UnsafeSetVar(name, value)
+	ctx.SetVar(ControlImportPath, init_import_path)
+}
+
+func enable(ctx ExprContext, name string) {
+	if strings.HasPrefix(name, "_") {
+		ctx.SetVar(name, true)
+	} else {
+		ctx.SetVar("_"+name, true)
+	}
+}
+
+func disable(ctx ExprContext, name string) {
+	if strings.HasPrefix(name, "_") {
+		ctx.SetVar(name, false)
+	} else {
+		ctx.SetVar("_"+name, false)
+	}
+}
+
+func isEnabled(ctx ExprContext, name string) (status bool) {
+	if v, exists := ctx.GetVar(name); exists {
+		if b, ok := v.(bool); ok {
+			status = b
+		}
+	}
 	return
 }
 
-func initDefaultVars(ctx ExprContext) {
+func getControlString(ctx ExprContext, name string) (s string, exists bool) {
-	if _, exists := ctx.GetVar(ControlPreset); exists {
+	var v any
-		return
+	if v, exists = ctx.GetVar(name); exists {
+		s, exists = v.(string)
 	}
-	ctx.UnsafeSetVar(ControlPreset, true)
+	return
-	ctx.UnsafeSetVar(ControlBoolShortcut, true)
-	ctx.UnsafeSetVar(ControlSearchPath, init_search_path)
 }

data-cursor.go

@@ -1,305 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// data-cursors.go
-package expr
-
-import (
-	"io"
-	"slices"
-)
-
-type dataCursor struct {
-	ds        map[string]Functor
-	ctx       ExprContext
-	initState bool // true if no item has produced yet (this replace di initial Next() call in the contructor)
-	// cursorValid bool // true if resource is nil or if clean has not yet been called
-	index     int
-	count     int
-	current   any
-	lastErr   error
-	resource  any
-	nextFunc  Functor
-	cleanFunc Functor
-	resetFunc Functor
-}
-
-func NewDataCursor(ctx ExprContext, ds map[string]Functor, resource any) (dc *dataCursor) {
-	dc = &dataCursor{
-		ds:        ds,
-		initState: true,
-		// cursorValid: true,
-		index:     -1,
-		count:     0,
-		current:   nil,
-		lastErr:   nil,
-		resource:  resource,
-		ctx:       ctx.Clone(),
-		nextFunc:  ds[NextName],
-		cleanFunc: ds[CleanName],
-		resetFunc: ds[ResetName],
-	}
-	return
-}
-
-func (dc *dataCursor) Context() ExprContext {
-	return dc.ctx
-}
-
-func (dc *dataCursor) TypeName() string {
-	return "DataCursor"
-}
-
-// func mapToString(m map[string]Functor) string {
-// 	var sb strings.Builder
-// 	sb.WriteByte('{')
-// 	for key, _ := range m {
-// 		if sb.Len() > 1 {
-// 			sb.WriteString(fmt.Sprintf(", %q: func(){}", key))
-// 		} else {
-// 			sb.WriteString(fmt.Sprintf("%q: func(){}", key))
-// 		}
-// 	}
-// 	sb.WriteByte('}')
-// 	return sb.String()
-// }
-
-func (dc *dataCursor) String() string {
-	return "$()"
-	/*
-	   var sb strings.Builder
-	   sb.WriteString(fmt.Sprintf(`$(
-	   index: %d,
-	   ds:    %s,
-	   ctx:   `, dc.index, mapToString(dc.ds)))
-	   CtxToBuilder(&sb, dc.ctx, 1)
-	   sb.WriteByte(')')
-	   return sb.String()
-	*/
-}
-
-func (dc *dataCursor) HasOperation(name string) (exists bool) {
-	exists = slices.Contains([]string{CleanName, ResetName, CurrentName, IndexName}, name)
-	if !exists {
-		f, ok := dc.ds[name]
-		exists = ok && isFunctor(f)
-	}
-	return
-}
-
-func (dc *dataCursor) CallOperation(name string, args map[string]any) (value any, err error) {
-	if name == IndexName {
-		value = int64(dc.Index())
-	} else if name == CleanName {
-		err = dc.Clean()
-	} else if name == ResetName {
-		err = dc.Reset()
-	} else if functor, ok := dc.ds[name]; ok && isFunctor(functor) {
-		ctx := cloneContext(dc.ctx)
-		value, err = functor.InvokeNamed(ctx, name, args)
-		exportObjects(dc.ctx, ctx)
-	} else {
-		err = errNoOperation(name)
-	}
-	return
-}
-
-// func (dc *dataCursor) Reset() (err error) {
-// 	if dc.resetFunc != nil {
-// 		if dc.resource != nil {
-// 			ctx := cloneContext(dc.ctx)
-// 			actualParams := bindActualParams(dc.resetFunc, []any{dc.resource})
-// 			_, err = dc.resetFunc.InvokeNamed(ctx, ResetName, actualParams)
-// 			exportObjects(dc.ctx, ctx)
-// 			dc.index = -1
-// 			dc.count = 0
-// 			dc.initState = true
-// 			dc.current = nil
-// 			dc.lastErr = nil
-// 		} else {
-// 			err = errInvalidDataSource()
-// 		}
-// 	} else {
-// 		err = errNoOperation(ResetName)
-// 	}
-// 	return
-// }
-
-func (dc *dataCursor) Reset() (err error) {
-	if dc.resetFunc != nil {
-		ctx := cloneContext(dc.ctx)
-		actualParams := bindActualParams(dc.resetFunc, []any{dc.resource})
-		_, err = dc.resetFunc.InvokeNamed(ctx, ResetName, actualParams)
-		exportObjects(dc.ctx, ctx)
-	}
-	dc.index = -1
-	dc.count = 0
-	dc.initState = true
-	dc.current = nil
-	dc.lastErr = nil
-	return
-}
-
-func (dc *dataCursor) Clean() (err error) {
-	if dc.cleanFunc != nil {
-		ctx := cloneContext(dc.ctx)
-		actualParams := bindActualParams(dc.cleanFunc, []any{dc.resource})
-		_, err = dc.cleanFunc.InvokeNamed(ctx, CleanName, actualParams)
-		exportObjects(dc.ctx, ctx)
-	}
-	dc.lastErr = io.EOF
-	return
-}
-
-// func (dc *dataCursor) Clean() (err error) {
-// 	if dc.cleanFunc != nil {
-// 		if dc.resource != nil {
-// 			ctx := cloneContext(dc.ctx)
-// 			actualParams := bindActualParams(dc.cleanFunc, []any{dc.resource})
-// 			_, err = dc.cleanFunc.InvokeNamed(ctx, CleanName, actualParams)
-// 			exportObjects(dc.ctx, ctx)
-// 		} else {
-// 			err = errInvalidDataSource()
-// 		}
-// 	} else {
-// 		err = errNoOperation(CleanName)
-// 	}
-// 	return
-// }
-
-func (dc *dataCursor) Current() (item any, err error) { // must return io.EOF at the last item
-	dc.init()
-
-	if dc.current != nil {
-		item = dc.current
-	} else {
-		err = io.EOF
-	}
-	return
-}
-
-func (dc *dataCursor) checkFilter(filter Functor, item any) (accepted bool, err error) {
-	var v any
-	var ok bool
-	ctx := cloneContext(dc.ctx)
-
-	actualParams := bindActualParams(filter, []any{item, dc.index})
-	if v, err = filter.InvokeNamed(ctx, FilterName, actualParams); err == nil && v != nil {
-		if accepted, ok = v.(bool); !ok {
-			accepted = true // NOTE: A non-boolean value that is not nil means the item has been accepted
-		}
-	}
-	return
-}
-
-func (dc *dataCursor) mapItem(mapper Functor, item any) (mappedItem any, err error) {
-	ctx := cloneContext(dc.ctx)
-	actualParams := bindActualParams(mapper, []any{item, dc.index})
-	mappedItem, err = mapper.InvokeNamed(ctx, MapName, actualParams)
-	return
-}
-
-func (dc *dataCursor) init() {
-	if dc.initState {
-		dc.initState = false
-		dc.Next()
-	}
-}
-
-func (dc *dataCursor) Next() (current any, err error) { // must return io.EOF after the last item
-	if dc.initState {
-		dc.init()
-	} else if err = dc.lastErr; err != nil {
-		return
-	}
-	current = dc.current
-	filter := dc.ds[FilterName]
-	mapper := dc.ds[MapName]
-	var item any
-	for item == nil && dc.lastErr == nil {
-		ctx := cloneContext(dc.ctx)
-		dc.index++
-
-		actualParams := bindActualParams(dc.nextFunc, []any{dc.resource, dc.index})
-		if item, dc.lastErr = dc.nextFunc.InvokeNamed(ctx, NextName, actualParams); dc.lastErr == nil {
-			if item == nil {
-				dc.lastErr = io.EOF
-			} else {
-				accepted := true
-				if filter != nil {
-					if accepted, dc.lastErr = dc.checkFilter(filter, item); dc.lastErr != nil || !accepted {
-						item = nil
-					}
-				}
-				if accepted {
-					dc.count++
-				}
-				if item != nil && mapper != nil {
-					item, dc.lastErr = dc.mapItem(mapper, item)
-				}
-			}
-		}
-		exportObjects(dc.ctx, ctx)
-	}
-	dc.current = item
-	if dc.lastErr != nil {
-		dc.index--
-		dc.Clean()
-	}
-	return
-}
-
-// func (dc *dataCursor) Next() (current any, err error) { // must return io.EOF after the last item
-// 	if dc.initState {
-// 		dc.init()
-// 	} else if err = dc.lastErr; err != nil {
-// 		return
-// 	}
-// 	current = dc.current
-// 	if dc.resource != nil {
-// 		filter := dc.ds[FilterName]
-// 		mapper := dc.ds[MapName]
-// 		var item any
-// 		for item == nil && dc.lastErr == nil {
-// 			ctx := cloneContext(dc.ctx)
-// 			dc.index++
-
-// 			actualParams := bindActualParams(dc.nextFunc, []any{dc.resource, dc.index})
-// 			if item, dc.lastErr = dc.nextFunc.InvokeNamed(ctx, NextName, actualParams); dc.lastErr == nil {
-// 				if item == nil {
-// 					dc.lastErr = io.EOF
-// 				} else {
-// 					accepted := true
-// 					if filter != nil {
-// 						if accepted, dc.lastErr = dc.checkFilter(filter, item); dc.lastErr != nil || !accepted {
-// 							item = nil
-// 						}
-// 					}
-// 					if accepted {
-// 						dc.count++
-// 					}
-// 					if item != nil && mapper != nil {
-// 						item, dc.lastErr = dc.mapItem(mapper, item)
-// 					}
-// 				}
-// 			}
-// 			exportObjects(dc.ctx, ctx)
-// 		}
-// 		dc.current = item
-// 		if dc.lastErr != nil {
-// 			dc.index--
-// 			dc.Clean()
-// 		}
-// 	} else {
-// 		dc.lastErr = errInvalidDataSource()
-// 	}
-// 	return
-// }
-
-func (dc *dataCursor) Index() int {
-	return dc.index - 1
-}
-
-func (dc *dataCursor) Count() int {
-	return dc.count
-}

dict-type.go

@@ -1,166 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// dict-type.go
-package expr
-
-import (
-	"fmt"
-	"reflect"
-	"strings"
-)
-
-type DictType map[any]any
-
-func MakeDict() (dict *DictType) {
-	d := make(DictType)
-	dict = &d
-	return
-}
-
-func NewDict(dictAny map[any]any) (dict *DictType) {
-	var d DictType
-	if dictAny != nil {
-		d = make(DictType, len(dictAny))
-		for i, item := range dictAny {
-			d[i] = item
-		}
-	} else {
-		d = make(DictType)
-	}
-	dict = &d
-	return
-}
-
-func newDict(dictAny map[any]*term) (dict *DictType) {
-	// TODO Change with a call to NewDict()
-	var d DictType
-	if dictAny != nil {
-		d = make(DictType, len(dictAny))
-		for i, item := range dictAny {
-			d[i] = item
-		}
-	} else {
-		d = make(DictType)
-	}
-	dict = &d
-	return
-}
-
-func (dict *DictType) toMultiLine(sb *strings.Builder, opt FmtOpt) {
-	indent := GetFormatIndent(opt)
-	flags := GetFormatFlags(opt)
-	//sb.WriteString(strings.Repeat("  ", indent))
-	sb.WriteByte('{')
-
-	if len(*dict) > 0 {
-		innerOpt := MakeFormatOptions(flags, indent+1)
-		nest := strings.Repeat("  ", indent+1)
-		sb.WriteByte('\n')
-
-		first := true
-		for name, value := range *dict {
-			if first {
-				first = false
-			} else {
-				sb.WriteByte(',')
-				sb.WriteByte('\n')
-			}
-
-			sb.WriteString(nest)
-			if key, ok := name.(string); ok {
-				sb.WriteString(string('"') + key + string('"'))
-			} else {
-				sb.WriteString(fmt.Sprintf("%v", name))
-			}
-			sb.WriteString(": ")
-			if f, ok := value.(Formatter); ok {
-				sb.WriteString(f.ToString(innerOpt))
-			} else if _, ok = value.(Functor); ok {
-				sb.WriteString("func(){}")
-			} else {
-				sb.WriteString(fmt.Sprintf("%v", value))
-			}
-		}
-		sb.WriteByte('\n')
-		sb.WriteString(strings.Repeat("  ", indent))
-	}
-	sb.WriteString("}")
-}
-
-func (dict *DictType) ToString(opt FmtOpt) string {
-	var sb strings.Builder
-	flags := GetFormatFlags(opt)
-	if flags&MultiLine != 0 {
-		dict.toMultiLine(&sb, opt)
-	} else {
-		sb.WriteByte('{')
-		first := true
-		for key, value := range *dict {
-			if first {
-				first = false
-			} else {
-				sb.WriteString(", ")
-			}
-			if s, ok := key.(string); ok {
-				sb.WriteString(string('"') + s + string('"'))
-			} else {
-				sb.WriteString(fmt.Sprintf("%v", key))
-			}
-			sb.WriteString(": ")
-			if formatter, ok := value.(Formatter); ok {
-				sb.WriteString(formatter.ToString(opt))
-			} else if t, ok := value.(*term); ok {
-				sb.WriteString(t.String())
-			} else {
-				sb.WriteString(fmt.Sprintf("%#v", value))
-			}
-		}
-		sb.WriteByte('}')
-	}
-	return sb.String()
-}
-
-func (dict *DictType) String() string {
-	return dict.ToString(0)
-}
-
-func (dict *DictType) TypeName() string {
-	return "dict"
-}
-
-func (dict *DictType) hasKey(target any) (ok bool) {
-	for key := range *dict {
-		if ok = reflect.DeepEqual(key, target); ok {
-			break
-		}
-	}
-	return
-}
-
-func (dict *DictType) clone() (c *DictType) {
-	c = newDict(nil)
-	for k, v := range *dict {
-		(*c)[k] = v
-	}
-	return
-}
-
-func (dict *DictType) merge(second *DictType) {
-	if second != nil {
-		for k, v := range *second {
-			(*dict)[k] = v
-		}
-	}
-}
-
-func (dict *DictType) setItem(key any, value any) (err error) {
-	(*dict)[key] = value
-	return
-}
-
-////////////////
-
-type DictFormat interface {
-	ToDict() *DictType
-}

expr-context.go

@@ -1,29 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// expr-context.go
-package expr
-
-// ----Expression Context
-type ExprContext interface {
-	Clone() ExprContext
-	SetParent(ctx ExprContext)
-	GetParent() (ctx ExprContext)
-	GetVar(varName string) (value any, exists bool)
-	GetLast() any
-	SetVar(varName string, value any)
-	UnsafeSetVar(varName string, value any)
-
-	EnumVars(func(name string) (accept bool)) (varNames []string)
-	VarCount() int
-	DeleteVar(varName string)
-
-	EnumFuncs(func(name string) (accept bool)) (funcNames []string)
-	FuncCount() int
-	DeleteFunc(funcName string)
-
-	GetFuncInfo(name string) (item ExprFunc, exists bool)
-	Call(name string, args map[string]any) (result any, err error)
-	RegisterFuncInfo(info ExprFunc)
-	RegisterFunc(name string, f Functor, returnType string, param []ExprFuncParam) (funcInfo ExprFunc, err error)
-}

expr-function.go

@@ -1,39 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// expr-function.go
-package expr
-
-// ---- Functor interface
-type Functor interface {
-	Typer
-	InvokeNamed(ctx ExprContext, name string, args map[string]any) (result any, err error)
-	SetFunc(info ExprFunc)
-	GetFunc() ExprFunc
-	GetParams() []ExprFuncParam
-	GetDefinitionContext() ExprContext
-}
-
-// ---- Function Param Info
-type ExprFuncParam interface {
-	Name() string
-	Type() string
-	IsDefault() bool
-	IsOptional() bool
-	IsRepeat() bool
-	DefaultValue() any
-}
-
-// ---- Function Info
-type ExprFunc interface {
-	Formatter
-	Name() string
-	MinArgs() int
-	MaxArgs() int
-	Functor() Functor
-	Params() []ExprFuncParam
-	ParamSpec(paramName string) ExprFuncParam
-	ReturnType() string
-	PrepareCall(name string, actualParams map[string]any) (err error)
-	AllocContext(parentCtx ExprContext) (ctx ExprContext)
-}

expr.go

@@ -1,12 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// expr.go
-package expr
-
-// ----Expression interface
-type Expr interface {
-	Typer
-	Eval(ctx ExprContext) (result any, err error)
-	String() string
-}

expr_test.go

@@ -0,0 +1,72 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
+// expr_test.go
+package expr
+
+import (
+	"fmt"
+	"strings"
+	"testing"
+)
+
+func TestExpr(t *testing.T) {
+	type inputType struct {
+		source     string
+		wantResult any
+		wantErr    error
+	}
+
+	inputs := []inputType{
+		/*   1 */ {`fact=func(n){(n)?{1}::{n*fact(n-1)}}; fact(5)`, int64(120), nil},
+	}
+
+	succeeded := 0
+	failed := 0
+
+	inputs1 := []inputType{
+		{`f=openFile("/tmp/test2.txt"); line=readFile(f); closeFile(f); line`, "ciao", nil},
+		//{`f = func(op){op()}; f(func(){2})`, int64(2), nil},
+	}
+
+	for i, input := range inputs1 {
+		var expr Expr
+		var gotResult any
+		var gotErr error
+
+		ctx := NewSimpleFuncStore()
+		// ImportMathFuncs(ctx)
+		// ImportImportFunc(ctx)
+		ImportOsFuncs(ctx)
+		parser := NewParser(ctx)
+
+		logTest(t, i+1, input.source, input.wantResult, input.wantErr)
+
+		r := strings.NewReader(input.source)
+		scanner := NewScanner(r, DefaultTranslations())
+
+		good := true
+		if expr, gotErr = parser.Parse(scanner); gotErr == nil {
+			gotResult, gotErr = expr.Eval(ctx)
+		}
+
+		if gotResult != input.wantResult {
+			t.Errorf("%d: %q -> result = %v [%T], want %v [%T]", i+1, input.source, gotResult, gotResult, input.wantResult, input.wantResult)
+			good = false
+		}
+
+		if gotErr != input.wantErr {
+			if input.wantErr == nil || gotErr == nil || (gotErr.Error() != input.wantErr.Error()) {
+				t.Errorf("%d: %q -> err = <%v>, want <%v>", i+1, input.source, gotErr, input.wantErr)
+				good = false
+			}
+		}
+
+		if good {
+			succeeded++
+		} else {
+			failed++
+		}
+	}
+	t.Log(fmt.Sprintf("test count: %d, succeeded count: %d, failed count: %d", len(inputs), succeeded, failed))
+}

formatter.go

@@ -1,79 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// formatter.go
-package expr
-
-import "fmt"
-
-type FmtOpt uint32 // lower 16 bits hold a bit-mask, higher 16 bits hold an indentation number
-
-const (
-	TTY FmtOpt = 1 << iota
-	MultiLine
-	Truncate
-	Base2
-	Base8
-	Base10
-	Base16
-)
-
-const (
-	TruncateEllipsis = "(...)"
-	MinTruncateSize  = 10
-	TruncateSize     = MinTruncateSize + 15
-)
-
-func TruncateString(s string) (trunc string) {
-	finalPart := len(s) - (MinTruncateSize - len(TruncateEllipsis))
-	trunc = s[0:len(s)-MinTruncateSize] + TruncateEllipsis + s[finalPart:]
-	return
-}
-
-func MakeFormatOptions(flags FmtOpt, indent int) FmtOpt {
-	return FmtOpt(indent<<16) | flags
-}
-
-func GetFormatFlags(opt FmtOpt) FmtOpt {
-	return opt & 0xFFFF
-}
-
-func GetFormatIndent(opt FmtOpt) int {
-	return int(opt >> 16)
-}
-
-type Formatter interface {
-	ToString(options FmtOpt) string
-}
-
-func getFormatted(v any, opt FmtOpt) (text string) {
-	if v == nil {
-		text = "(nil)"
-	} else if s, ok := v.(string); ok {
-		text = s
-	} else if formatter, ok := v.(Formatter); ok {
-		text = formatter.ToString(opt)
-	} else {
-		text = fmt.Sprintf("%v", v)
-	}
-	return
-}
-
-type Typer interface {
-	TypeName() string
-}
-
-func TypeName(v any) (name string) {
-	if v == nil {
-		name = "nil"
-	} else if typer, ok := v.(Typer); ok {
-		name = typer.TypeName()
-	} else if IsInteger(v) {
-		name = "integer"
-	} else if IsFloat(v) {
-		name = "float"
-	} else {
-		name = fmt.Sprintf("%T", v)
-	}
-	return
-}

fraction-type.go

@@ -1,361 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// fraction-type.go
-package expr
-
-//https://www.youmath.it/lezioni/algebra-elementare/lezioni-di-algebra-e-aritmetica-per-scuole-medie/553-dalle-frazioni-a-numeri-decimali.html
-
-import (
-	"errors"
-	"fmt"
-	"math"
-	"strconv"
-	"strings"
-)
-
-type FractionType struct {
-	num, den int64
-}
-
-func newFraction(num, den int64) *FractionType {
-	num, den = simplifyIntegers(num, den)
-	return &FractionType{num, den}
-}
-
-func float64ToFraction(f float64) (fract *FractionType, err error) {
-	var sign string
-	intPart, decPart := math.Modf(f)
-	if decPart < 0.0 {
-		sign = "-"
-		intPart = -intPart
-		decPart = -decPart
-	}
-	dec := fmt.Sprintf("%.12f", decPart)
-	s := fmt.Sprintf("%s%.f%s", sign, intPart, dec[1:])
-	return makeGeneratingFraction(s)
-}
-
-// Based on https://cs.opensource.google/go/go/+/refs/tags/go1.22.3:src/math/big/rat.go;l=39
-func makeGeneratingFraction(s string) (f *FractionType, err error) {
-	var num, den int64
-	var sign int64 = 1
-	var parts []string
-	if len(s) == 0 {
-		goto exit
-	}
-	if s[0] == '-' {
-		sign = int64(-1)
-		s = s[1:]
-	} else if s[0] == '+' {
-		s = s[1:]
-	}
-	//	if strings.HasSuffix(s, "()") {
-	//		s = s[0 : len(s)-2]
-	//	}
-	s = strings.TrimSuffix(s, "()")
-	parts = strings.SplitN(s, ".", 2)
-	if num, err = strconv.ParseInt(parts[0], 10, 64); err != nil {
-		return
-	}
-	if len(parts) == 1 {
-		f = newFraction(sign*num, 1)
-	} else if len(parts) == 2 {
-		subParts := strings.SplitN(parts[1], "(", 2)
-		if len(subParts) == 1 {
-			den = 1
-			dec := parts[1]
-			lsd := len(dec)
-			for i := lsd - 1; i >= 0 && dec[i] == '0'; i-- {
-				lsd--
-			}
-			for _, c := range dec[0:lsd] {
-				if c < '0' || c > '9' {
-					return nil, ErrExpectedGot("fract", "digit", c)
-				}
-				num = num*10 + int64(c-'0')
-				den = den * 10
-			}
-			f = newFraction(sign*num, den)
-		} else if len(subParts) == 2 {
-			sub := num
-			mul := int64(1)
-			for _, c := range subParts[0] {
-				if c < '0' || c > '9' {
-					return nil, ErrExpectedGot("fract", "digit", c)
-				}
-				num = num*10 + int64(c-'0')
-				sub = sub*10 + int64(c-'0')
-				mul *= 10
-			}
-			if len(subParts) == 2 {
-				if s[len(s)-1] != ')' {
-					goto exit
-				}
-				p := subParts[1][0 : len(subParts[1])-1]
-				for _, c := range p {
-					if c < '0' || c > '9' {
-						return nil, ErrExpectedGot("fract", "digit", c)
-					}
-					num = num*10 + int64(c-'0')
-					den = den*10 + 9
-				}
-				den *= mul
-			}
-			num -= sub
-			f = newFraction(sign*num, den)
-		}
-	}
-exit:
-	if f == nil {
-		err = errors.New("bad syntax")
-	}
-	return
-}
-
-func (f *FractionType) toFloat() float64 {
-	return float64(f.num) / float64(f.den)
-}
-
-func (f *FractionType) String() string {
-	return f.ToString(0)
-}
-
-func (f *FractionType) ToString(opt FmtOpt) string {
-	var sb strings.Builder
-	if opt&MultiLine == 0 {
-		sb.WriteString(fmt.Sprintf("%d:%d", f.num, f.den))
-	} else {
-		var sign, num string
-		if f.num < 0 && opt&TTY == 0 {
-			num = strconv.FormatInt(-f.num, 10)
-			sign = "-"
-		} else {
-			num = strconv.FormatInt(f.num, 10)
-		}
-		den := strconv.FormatInt(f.den, 10)
-		size := max(len(num), len(den))
-		if opt&TTY != 0 {
-			sNum := fmt.Sprintf("\x1b[4m%[1]*s\x1b[0m\n", -size, fmt.Sprintf("%[1]*s", (size+len(num))/2, sign+num))
-			sb.WriteString(sNum)
-		} else {
-			if len(sign) > 0 {
-				sb.WriteString("  ")
-			}
-			sb.WriteString(fmt.Sprintf("%[1]*s", -size, fmt.Sprintf("%[1]*s", (size+len(num))/2, num)))
-			sb.WriteByte('\n')
-			if len(sign) > 0 {
-				sb.WriteString(sign)
-				sb.WriteByte(' ')
-			}
-			sb.WriteString(strings.Repeat("-", size))
-			sb.WriteByte('\n')
-			if len(sign) > 0 {
-				sb.WriteString("  ")
-			}
-		}
-		sDen := fmt.Sprintf("%[1]*s", size, fmt.Sprintf("%[1]*s", (size+len(den))/2, den))
-		sb.WriteString(sDen)
-	}
-
-	return sb.String()
-}
-
-func (f *FractionType) TypeName() string {
-	return "fraction"
-}
-
-// -------- fraction utility functions
-
-// greatest common divider
-func gcd(a, b int64) (g int64) {
-	if a < 0 {
-		a = -a
-	}
-	if b < 0 {
-		b = -b
-	}
-	if a < b {
-		a, b = b, a
-	}
-	r := a % b
-	for r > 0 {
-		a, b = b, r
-		r = a % b
-	}
-	g = b
-	return
-}
-
-// lower common multiple
-func lcm(a, b int64) (l int64) {
-	g := gcd(a, b)
-	l = a * b / g
-	return
-}
-
-// Sum two fractions
-func sumFract(f1, f2 *FractionType) (sum *FractionType) {
-	m := lcm(f1.den, f2.den)
-	sum = newFraction(f1.num*(m/f1.den)+f2.num*(m/f2.den), m)
-	return
-}
-
-// Multiply two fractions
-func mulFract(f1, f2 *FractionType) (prod *FractionType) {
-	prod = newFraction(f1.num*f2.num, f1.den*f2.den)
-	return
-}
-
-func anyToFract(v any) (f *FractionType, err error) {
-	var ok bool
-	if f, ok = v.(*FractionType); !ok {
-		if n, ok := v.(int64); ok {
-			f = intToFraction(n)
-		}
-	}
-	if f == nil {
-		err = ErrExpectedGot("fract", TypeFraction, v)
-	}
-	return
-}
-
-func anyPairToFract(v1, v2 any) (f1, f2 *FractionType, err error) {
-	if f1, err = anyToFract(v1); err != nil {
-		return
-	}
-	if f2, err = anyToFract(v2); err != nil {
-		return
-	}
-	return
-}
-
-func sumAnyFract(af1, af2 any) (sum any, err error) {
-	var f1, f2 *FractionType
-	if f1, f2, err = anyPairToFract(af1, af2); err != nil {
-		return
-	}
-	f := sumFract(f1, f2)
-	if f.num == 0 {
-		sum = 0
-	} else {
-		sum = simplifyFraction(f)
-	}
-	return
-}
-
-// Returns
-//
-//		 <0 if af1 < af2
-//		 =0 if af1 == af2
-//		 >0 if af1 > af2
-//	 err if af1 or af2 is not convertible to fraction
-func cmpAnyFract(af1, af2 any) (result int, err error) {
-	var f1, f2 *FractionType
-	if f1, f2, err = anyPairToFract(af1, af2); err != nil {
-		return
-	}
-	result = cmpFract(f1, f2)
-	return
-}
-
-// Returns
-//
-//	<0 if af1 < af2
-//	=0 if af1 == af2
-//	>0 if af1 > af2
-func cmpFract(f1, f2 *FractionType) (result int) {
-	f2.num = -f2.num
-	f := sumFract(f1, f2)
-	if f.num < 0 {
-		result = -1
-	} else if f.num > 0 {
-		result = 1
-	} else {
-		result = 0
-	}
-	return
-}
-
-func subAnyFract(af1, af2 any) (sum any, err error) {
-	var f1, f2 *FractionType
-	if f1, f2, err = anyPairToFract(af1, af2); err != nil {
-		return
-	}
-	f2.num = -f2.num
-	f := sumFract(f1, f2)
-	if f.num == 0 {
-		sum = 0
-	} else {
-		sum = simplifyFraction(f)
-	}
-	return
-}
-
-func mulAnyFract(af1, af2 any) (prod any, err error) {
-	var f1, f2 *FractionType
-	if f1, f2, err = anyPairToFract(af1, af2); err != nil {
-		return
-	}
-	if f1.num == 0 || f2.num == 0 {
-		prod = 0
-	} else {
-		f := &FractionType{f1.num * f2.num, f1.den * f2.den}
-		prod = simplifyFraction(f)
-	}
-	return
-}
-
-func divAnyFract(af1, af2 any) (quot any, err error) {
-	var f1, f2 *FractionType
-	if f1, f2, err = anyPairToFract(af1, af2); err != nil {
-		return
-	}
-	if f2.num == 0 {
-		err = errors.New("division by zero")
-		return
-	}
-	if f1.num == 0 || f2.den == 0 {
-		quot = 0
-	} else {
-		f := &FractionType{f1.num * f2.den, f1.den * f2.num}
-		quot = simplifyFraction(f)
-	}
-	return
-}
-
-func simplifyFraction(f *FractionType) (v any) {
-	f.num, f.den = simplifyIntegers(f.num, f.den)
-	if f.den == 1 {
-		v = f.num
-	} else {
-		v = &FractionType{f.num, f.den}
-	}
-	return v
-}
-
-func simplifyIntegers(num, den int64) (a, b int64) {
-	if num == 0 {
-		return 0, 1
-	}
-	if den == 0 {
-		panic("fraction with denominator == 0")
-	}
-	if den < 0 {
-		den = -den
-		num = -num
-	}
-	g := gcd(num, den)
-	a = num / g
-	b = den / g
-	return
-}
-
-func intToFraction(n int64) *FractionType {
-	return &FractionType{n, 1}
-}
-
-func isFraction(v any) (ok bool) {
-	_, ok = v.(*FractionType)
-	return ok
-}

func-import.go

@@ -0,0 +1,142 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
+// func-import.go
+package expr
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"path"
+	"path/filepath"
+	"strings"
+)
+
+const ENV_EXPR_PATH = "EXPR_PATH"
+
+func importFunc(ctx ExprContext, name string, args []any) (result any, err error) {
+	return importGeneral(ctx, name, args)
+}
+
+func includeFunc(ctx ExprContext, name string, args []any) (result any, err error) {
+	enable(ctx, control_export_all)
+	return importGeneral(ctx, name, args)
+}
+
+func importGeneral(ctx ExprContext, name string, args []any) (result any, err error) {
+	var dirList []string
+
+	dirList = addEnvImportDirs(dirList)
+	dirList = addPresetImportDirs(ctx, dirList)
+	result, err = doImport(ctx, name, dirList, NewFlatArrayIterator(args))
+	return
+}
+
+func checkStringParamExpected(funcName string, paramValue any, paramPos int) (err error) {
+	if !(isString(paramValue) /*|| isList(paramValue)*/) {
+		err = fmt.Errorf("%s(): param nr %d has wrong type %T, string expected", funcName, paramPos+1, paramValue)
+	}
+	return
+}
+
+func addEnvImportDirs(dirList []string) []string {
+	if dirSpec, exists := os.LookupEnv(ENV_EXPR_PATH); exists {
+		dirs := strings.Split(dirSpec, ":")
+		if dirList == nil {
+			dirList = dirs
+		} else {
+			dirList = append(dirList, dirs...)
+		}
+	}
+	return dirList
+}
+
+func addPresetImportDirs(ctx ExprContext, dirList []string) []string {
+	if dirSpec, exists := getControlString(ctx, ControlImportPath); exists {
+		dirs := strings.Split(dirSpec, ":")
+		if dirList == nil {
+			dirList = dirs
+		} else {
+			dirList = append(dirList, dirs...)
+		}
+	}
+	return dirList
+}
+
+func isFile(filePath string) bool {
+	info, err := os.Stat(filePath)
+	return (err == nil || errors.Is(err, os.ErrExist)) && info.Mode().IsRegular()
+}
+
+func searchAmongPath(filename string, dirList []string) (filePath string) {
+	for _, dir := range dirList {
+		if fullPath := path.Join(dir, filename); isFile(fullPath) {
+			filePath = fullPath
+			break
+		}
+	}
+	return
+}
+
+func isPathRelative(filePath string) bool {
+	unixPath := filepath.ToSlash(filePath)
+	return strings.HasPrefix(unixPath, "./") || strings.HasPrefix(unixPath, "../")
+}
+
+func makeFilepath(filename string, dirList []string) (filePath string, err error) {
+	if path.IsAbs(filename) || isPathRelative(filename) {
+		if isFile(filename) {
+			filePath = filename
+		}
+	} else {
+		filePath = searchAmongPath(filename, dirList)
+	}
+	if len(filePath) == 0 {
+		err = fmt.Errorf("source file %q not found", filename)
+	}
+	return
+}
+
+func doImport(ctx ExprContext, name string, dirList []string, it Iterator) (result any, err error) {
+	var v any
+	var sourceFilepath string
+
+	for v, err = it.Next(); err == nil; v, err = it.Next() {
+		if err = checkStringParamExpected(name, v, it.Index()); err != nil {
+			break
+		}
+		if sourceFilepath, err = makeFilepath(v.(string), dirList); err != nil {
+			break
+		}
+		var file *os.File
+		if file, err = os.Open(sourceFilepath); err == nil {
+			defer file.Close()
+			var expr *ast
+			scanner := NewScanner(file, DefaultTranslations())
+			parser := NewParser(ctx)
+			if expr, err = parser.parseGeneral(scanner, true, true); err == nil {
+				result, err = expr.eval(ctx, false)
+			}
+			if err != nil {
+				break
+			}
+		} else {
+			break
+		}
+	}
+	if err != nil {
+		if err == io.EOF {
+			err = nil
+		} else {
+			result = nil
+		}
+	}
+	return
+}
+
+func ImportImportFuncs(ctx ExprContext) {
+	ctx.RegisterFunc("import", &simpleFunctor{f: importFunc}, 1, -1)
+	ctx.RegisterFunc("include", &simpleFunctor{f: includeFunc}, 1, -1)
+}

func-math.go

@@ -0,0 +1,114 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
+// funcs-math.go
+package expr
+
+import (
+	"fmt"
+	"io"
+)
+
+func checkNumberParamExpected(funcName string, paramValue any, paramPos int) (err error) {
+	if !(isNumber(paramValue) || isList(paramValue)) {
+		err = fmt.Errorf("%s(): param nr %d has wrong type %T, number expected", funcName, paramPos+1, paramValue)
+	}
+	return
+}
+
+func doAdd(ctx ExprContext, name string, it Iterator) (result any, err error) {
+	var sumAsFloat = false
+	var floatSum float64 = 0.0
+	var intSum int64 = 0
+	var v any
+
+	for v, err = it.Next(); err == nil; v, err = it.Next() {
+		if err = checkNumberParamExpected(name, v, it.Index()); err != nil {
+			break
+		}
+
+		if array, ok := v.([]any); ok {
+			if v, err = doAdd(ctx, name, NewFlatArrayIterator(array)); err != nil {
+				break
+			}
+		}
+
+		if !sumAsFloat && isFloat(v) {
+			sumAsFloat = true
+			floatSum = float64(intSum)
+		}
+		if sumAsFloat {
+			floatSum += numAsFloat(v)
+		} else {
+			iv, _ := v.(int64)
+			intSum += iv
+		}
+	}
+	if err == nil || err == io.EOF {
+		err = nil
+		if sumAsFloat {
+			result = floatSum
+		} else {
+			result = intSum
+		}
+	}
+	return
+}
+
+func addFunc(ctx ExprContext, name string, args []any) (result any, err error) {
+	result, err = doAdd(ctx, name, NewFlatArrayIterator(args))
+	return
+}
+
+func doMul(ctx ExprContext, name string, it Iterator) (result any, err error) {
+	var mulAsFloat = false
+	var floatProd float64 = 1.0
+	var intProd int64 = 1
+	var v any
+
+	for v, err = it.Next(); err == nil; v, err = it.Next() {
+		if err = checkNumberParamExpected(name, v, it.Index()); err != nil {
+			break
+		}
+
+		if array, ok := v.([]any); ok {
+			if v, err = doAdd(ctx, name, NewFlatArrayIterator(array)); err != nil {
+				break
+			}
+		}
+
+		if !mulAsFloat && isFloat(v) {
+			mulAsFloat = true
+			floatProd = float64(intProd)
+		}
+		if mulAsFloat {
+			floatProd *= numAsFloat(v)
+		} else {
+			iv, _ := v.(int64)
+			intProd *= iv
+		}
+	}
+	if err == nil || err == io.EOF {
+		err = nil
+		if mulAsFloat {
+			result = floatProd
+		} else {
+			result = intProd
+		}
+	}
+	return
+}
+
+func mulFunc(ctx ExprContext, name string, args []any) (result any, err error) {
+	result, err = doMul(ctx, name, NewFlatArrayIterator(args))
+	return
+}
+
+func ImportMathFuncs(ctx ExprContext) {
+	ctx.RegisterFunc("add", &simpleFunctor{f: addFunc}, 0, -1)
+	ctx.RegisterFunc("mul", &simpleFunctor{f: mulFunc}, 0, -1)
+}
+
+func init() {
+	registerImport("math.arith", ImportMathFuncs)
+}

func-os.go

@@ -0,0 +1,164 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
+// func-os.go
+package expr
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"os"
+)
+
+type osHandle interface {
+	getFile() *os.File
+}
+
+type osWriter struct {
+	fh     *os.File
+	writer *bufio.Writer
+}
+
+func (h *osWriter) getFile() *os.File {
+	return h.fh
+}
+
+type osReader struct {
+	fh     *os.File
+	reader *bufio.Reader
+}
+
+func (h *osReader) getFile() *os.File {
+	return h.fh
+}
+
+func createFileFunc(ctx ExprContext, name string, args []any) (result any, err error) {
+	var filePath string
+	if len(args) > 0 {
+		filePath, _ = args[0].(string)
+	}
+
+	if len(filePath) > 0 {
+		var fh *os.File
+		if fh, err = os.Create(filePath); err == nil {
+			result = &osWriter{fh: fh, writer: bufio.NewWriter(fh)}
+		}
+	} else {
+		err = fmt.Errorf("%s(): missing the file path", name)
+	}
+	return
+}
+
+func openFileFunc(ctx ExprContext, name string, args []any) (result any, err error) {
+	var filePath string
+	if len(args) > 0 {
+		filePath, _ = args[0].(string)
+	}
+
+	if len(filePath) > 0 {
+		var fh *os.File
+		if fh, err = os.Open(filePath); err == nil {
+			result = &osReader{fh: fh, reader: bufio.NewReader(fh)}
+		}
+	} else {
+		err = fmt.Errorf("%s(): missing the file path", name)
+	}
+	return
+}
+
+func appendFileFunc(ctx ExprContext, name string, args []any) (result any, err error) {
+	var filePath string
+	if len(args) > 0 {
+		filePath, _ = args[0].(string)
+	}
+
+	if len(filePath) > 0 {
+		var fh *os.File
+		if fh, err = os.OpenFile(filePath, os.O_APPEND|os.O_WRONLY|os.O_CREATE, 0660); err == nil {
+			result = &osWriter{fh: fh, writer: bufio.NewWriter(fh)}
+		}
+	} else {
+		err = fmt.Errorf("%s(): missing the file path", name)
+	}
+	return
+}
+
+func closeFileFunc(ctx ExprContext, name string, args []any) (result any, err error) {
+	var handle osHandle
+
+	if len(args) > 0 {
+		handle, _ = args[0].(osHandle)
+	}
+
+	if handle != nil {
+		if fh := handle.getFile(); fh != nil {
+			if w, ok := handle.(*osWriter); ok {
+				err = w.writer.Flush()
+			}
+			if err == nil {
+				err = fh.Close()
+			}
+		}
+	} else {
+		err = fmt.Errorf("%s(): invalid file handle", name)
+	}
+	result = err == nil
+	return
+}
+
+func writeFileFunc(ctx ExprContext, name string, args []any) (result any, err error) {
+	var handle osHandle
+
+	if len(args) > 0 {
+		handle, _ = args[0].(osHandle)
+	}
+
+	if handle != nil {
+		if fh := handle.getFile(); fh != nil {
+			if w, ok := handle.(*osWriter); ok {
+				result, err = fmt.Fprint(w.writer, args[1:]...)
+			}
+		}
+	}
+	return
+}
+
+func readFileFunc(ctx ExprContext, name string, args []any) (result any, err error) {
+	var handle osHandle
+
+	if len(args) > 0 {
+		handle, _ = args[0].(osHandle)
+	}
+
+	if handle != nil {
+		if fh := handle.getFile(); fh != nil {
+			if r, ok := handle.(*osReader); ok {
+				var limit byte = '\n'
+				var v string
+				if len(args) > 1 {
+					if s, ok := args[1].(string); ok && len(s) > 0 {
+						limit = s[0]
+					}
+				}
+				if v, err = r.reader.ReadString(limit); err == nil || err == io.EOF {
+					if len(v) > 0 && v[len(v)-1] == limit {
+						result = v[0 : len(v)-1]
+					} else {
+						result = v
+					}
+				}
+			}
+		}
+	}
+	return
+}
+
+func ImportOsFuncs(ctx ExprContext) {
+	ctx.RegisterFunc("openFile", &simpleFunctor{f: openFileFunc}, 1, 1)
+	ctx.RegisterFunc("appendFile", &simpleFunctor{f: appendFileFunc}, 1, 1)
+	ctx.RegisterFunc("createFile", &simpleFunctor{f: createFileFunc}, 1, 1)
+	ctx.RegisterFunc("writeFile", &simpleFunctor{f: writeFileFunc}, 1, -1)
+	ctx.RegisterFunc("readFile", &simpleFunctor{f: readFileFunc}, 1, 2)
+	ctx.RegisterFunc("closeFile", &simpleFunctor{f: closeFileFunc}, 1, 1)
+}

function-register.go

@@ -0,0 +1,47 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
+// function-register.go
+package expr
+
+import (
+	"path/filepath"
+)
+
+var functionRegister map[string]func(ExprContext)
+
+func registerImport(name string, importFunc func(ExprContext)) {
+	if functionRegister == nil {
+		functionRegister = make(map[string]func(ExprContext))
+	}
+	functionRegister[name] = importFunc
+}
+
+func ImportInContext(ctx ExprContext, name string) (exists bool) {
+	var importFunc func(ExprContext)
+	if importFunc, exists = functionRegister[name]; exists {
+		importFunc(ctx)
+	}
+	return
+}
+
+func ImportInContextByGlobPattern(ctx ExprContext, pattern string) (count int, err error) {
+	var matched bool
+	for name, importFunc := range functionRegister {
+		if matched, err = filepath.Match(pattern, name); err == nil {
+			if matched {
+				count++
+				importFunc(ctx)
+			}
+		} else {
+			break
+		}
+	}
+	return
+}
+
+func init() {
+	if functionRegister == nil {
+		functionRegister = make(map[string]func(ExprContext))
+	}
+}

function.go

@@ -1,386 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// function.go
-package expr
-
-import (
-	"fmt"
-	"strconv"
-	"strings"
-)
-
-// ---- Function template
-type FuncTemplate func(ctx ExprContext, name string, args map[string]any) (result any, err error)
-
-// ---- Common functor definition
-type baseFunctor struct {
-	info ExprFunc
-}
-
-func (functor *baseFunctor) ToString(opt FmtOpt) (s string) {
-	if functor.info != nil {
-		s = functor.info.ToString(opt)
-	} else {
-		s = "func(){}"
-	}
-	return s
-}
-
-func (functor *baseFunctor) GetParams() (params []ExprFuncParam) {
-	if functor.info != nil {
-		return functor.info.Params()
-	} else {
-		return []ExprFuncParam{}
-	}
-}
-
-func (functor *baseFunctor) SetFunc(info ExprFunc) {
-	functor.info = info
-}
-
-func (functor *baseFunctor) GetFunc() ExprFunc {
-	return functor.info
-}
-
-func (functor *baseFunctor) GetDefinitionContext() ExprContext {
-	return nil
-}
-
-// ---- Function Parameters
-type paramFlags uint16
-
-const (
-	PfDefault paramFlags = 1 << iota
-	PfOptional
-	PfRepeat
-)
-
-type funcParamInfo struct {
-	name         string
-	flags        paramFlags
-	defaultValue any
-}
-
-func NewFuncParam(name string) ExprFuncParam {
-	return &funcParamInfo{name: name}
-}
-
-func NewFuncParamFlag(name string, flags paramFlags) ExprFuncParam {
-	return &funcParamInfo{name: name, flags: flags}
-}
-
-func NewFuncParamFlagDef(name string, flags paramFlags, defValue any) *funcParamInfo {
-	return &funcParamInfo{name: name, flags: flags, defaultValue: defValue}
-}
-
-func (param *funcParamInfo) Name() string {
-	return param.name
-}
-
-func (param *funcParamInfo) Type() string {
-	return TypeAny
-}
-
-func (param *funcParamInfo) IsDefault() bool {
-	return (param.flags & PfDefault) != 0
-}
-
-func (param *funcParamInfo) IsOptional() bool {
-	return (param.flags & PfOptional) != 0
-}
-
-func (param *funcParamInfo) IsRepeat() bool {
-	return (param.flags & PfRepeat) != 0
-}
-
-func (param *funcParamInfo) DefaultValue() any {
-	return param.defaultValue
-}
-
-// --- Functions
-
-// funcInfo implements ExprFunc
-type funcInfo struct {
-	name         string
-	minArgs      int
-	maxArgs      int
-	functor      Functor
-	formalParams []ExprFuncParam
-	returnType   string
-}
-
-func newFuncInfo(name string, functor Functor, returnType string, params []ExprFuncParam) (info *funcInfo, err error) {
-	var minArgs = 0
-	var maxArgs = 0
-	for _, p := range params {
-		if maxArgs == -1 {
-			return nil, fmt.Errorf("no more params can be specified after the ellipsis symbol: %q", p.Name())
-		}
-		if p.IsDefault() || p.IsOptional() {
-			maxArgs++
-		} else if maxArgs == minArgs {
-			minArgs++
-			maxArgs++
-		} else {
-			return nil, fmt.Errorf("can't specify non-optional param after optional ones: %q", p.Name())
-		}
-		if p.IsRepeat() {
-			minArgs--
-			maxArgs = -1
-		}
-	}
-
-	info = &funcInfo{
-		name: name, minArgs: minArgs, maxArgs: maxArgs, functor: functor, returnType: returnType, formalParams: params,
-	}
-	functor.SetFunc(info)
-	return info, nil
-}
-
-func (info *funcInfo) Params() []ExprFuncParam {
-	return info.formalParams
-}
-
-func (info *funcInfo) ReturnType() string {
-	return info.returnType
-}
-
-func (info *funcInfo) ToString(opt FmtOpt) string {
-	var sb strings.Builder
-	if len(info.Name()) == 0 {
-		sb.WriteString("func")
-	} else {
-		sb.WriteString(info.Name())
-	}
-	sb.WriteByte('(')
-	if info.formalParams != nil {
-		for i, p := range info.formalParams {
-			if i > 0 {
-				sb.WriteString(", ")
-			}
-			sb.WriteString(p.Name())
-
-			if p.IsDefault() {
-				sb.WriteByte('=')
-				if s, ok := p.DefaultValue().(string); ok {
-					sb.WriteByte('"')
-					sb.WriteString(s)
-					sb.WriteByte('"')
-				} else {
-					sb.WriteString(fmt.Sprintf("%v", p.DefaultValue()))
-				}
-			}
-		}
-	}
-	if info.maxArgs < 0 {
-		sb.WriteString(" ...")
-	}
-	sb.WriteString("):")
-	if len(info.returnType) > 0 {
-		sb.WriteString(info.returnType)
-	} else {
-		sb.WriteString(TypeAny)
-	}
-	sb.WriteString("{}")
-	return sb.String()
-}
-
-func (info *funcInfo) Name() string {
-	return info.name
-}
-
-func (info *funcInfo) MinArgs() int {
-	return info.minArgs
-}
-
-func (info *funcInfo) MaxArgs() int {
-	return info.maxArgs
-}
-
-func (info *funcInfo) Functor() Functor {
-	return info.functor
-}
-
-func (info *funcInfo) AllocContext(parentCtx ExprContext) (ctx ExprContext) {
-	if defCtx := info.functor.GetDefinitionContext(); defCtx != nil {
-		ctx = defCtx.Clone()
-		ctx.SetParent(defCtx)
-	} else {
-		ctx = parentCtx.Clone()
-		ctx.SetParent(parentCtx)
-	}
-	return
-}
-
-func (info *funcInfo) ParamSpec(paramName string) ExprFuncParam {
-	for _, spec := range info.formalParams {
-		if spec.Name() == paramName {
-			return spec
-		}
-	}
-	return nil
-}
-
-func initActualParams(ctx ExprContext, info ExprFunc, callTerm *term) (actualParams map[string]any, err error) {
-	var varArgs []any
-	var varName string
-
-	namedParamsStarted := false
-
-	formalParams := info.Params()
-	actualParams = make(map[string]any, len(formalParams))
-	if callTerm == nil {
-		return
-	}
-
-	for i, tree := range callTerm.children {
-		var paramValue any
-		paramCtx := ctx.Clone()
-		if paramValue, err = tree.compute(paramCtx); err != nil {
-			break
-		}
-		if paramName, namedParam := getAssignVarName(tree); namedParam {
-			if info.ParamSpec(paramName) == nil {
-				err = fmt.Errorf("%s(): unknown param %q", info.Name(), paramName)
-				break
-			}
-			actualParams[paramName] = paramValue
-			namedParamsStarted = true
-		} else if !namedParamsStarted {
-			if varArgs != nil {
-				varArgs = append(varArgs, paramValue)
-			} else if i < len(formalParams) {
-				spec := formalParams[i]
-				if spec.IsRepeat() {
-					varArgs = make([]any, 0, len(callTerm.children)-i)
-					varArgs = append(varArgs, paramValue)
-					varName = spec.Name()
-				} else {
-					actualParams[spec.Name()] = paramValue
-				}
-			} else {
-				err = ErrTooManyParams(info.Name(), len(formalParams), len(callTerm.children))
-				break
-			}
-		} else {
-			err = fmt.Errorf("%s(): positional param nr %d not allowed after named params", info.Name(), i+1)
-			break
-		}
-	}
-	if err == nil {
-		if varArgs != nil {
-			actualParams[varName] = varArgs
-		}
-	}
-	return
-}
-
-func (info *funcInfo) PrepareCall(name string, actualParams map[string]any) (err error) {
-	passedCount := len(actualParams)
-	if info.MinArgs() > passedCount {
-		err = ErrTooFewParams(name, info.MinArgs(), info.MaxArgs(), passedCount)
-		return
-	}
-
-	if passedCount < len(info.formalParams) {
-		for _, p := range info.formalParams {
-			if _, exists := actualParams[p.Name()]; !exists {
-				if !p.IsDefault() {
-					break
-				}
-				if p.IsRepeat() {
-					varArgs := make([]any, 1)
-					varArgs[0] = p.DefaultValue()
-					actualParams[p.Name()] = varArgs
-				} else {
-					actualParams[p.Name()] = p.DefaultValue()
-				}
-			}
-		}
-	}
-
-	if info.MaxArgs() >= 0 && info.MaxArgs() < len(actualParams) {
-		err = ErrTooManyParams(name, info.MaxArgs(), len(actualParams))
-	}
-	return
-}
-
-// ----- Call a function ---
-
-func getAssignVarName(t *term) (name string, ok bool) {
-	if ok = t.symbol() == SymEqual; ok {
-		name = t.children[0].source()
-	}
-	return
-}
-
-func CallFunctionByTerm(parentCtx ExprContext, name string, callTerm *term) (result any, err error) {
-	var actualParams map[string]any
-	if info, exists := GetFuncInfo(parentCtx, name); exists {
-		if actualParams, err = initActualParams(parentCtx, info, callTerm); err == nil {
-			ctx := info.AllocContext(parentCtx)
-			if err = info.PrepareCall(name, actualParams); err == nil {
-				functor := info.Functor()
-				result, err = functor.InvokeNamed(ctx, name, actualParams)
-				exportObjectsToParent(ctx)
-			}
-		}
-	} else {
-		err = fmt.Errorf("unknown function %s()", name)
-	}
-	return
-}
-
-func CallFunctionByArgs(parentCtx ExprContext, name string, args []any) (result any, err error) {
-	var actualParams map[string]any
-	if info, exists := GetFuncInfo(parentCtx, name); exists {
-		functor := info.Functor()
-		actualParams = bindActualParams(functor, args)
-		ctx := info.AllocContext(parentCtx)
-		if err = info.PrepareCall(name, actualParams); err == nil {
-			result, err = functor.InvokeNamed(ctx, name, actualParams)
-			exportObjectsToParent(ctx)
-		}
-	} else {
-		err = fmt.Errorf("unknown function %s()", name)
-	}
-	return
-}
-
-func CallFunctionByParams(parentCtx ExprContext, name string, actualParams map[string]any) (result any, err error) {
-	//var actualParams map[string]any
-	if info, exists := GetFuncInfo(parentCtx, name); exists {
-		functor := info.Functor()
-		ctx := info.AllocContext(parentCtx)
-		if err = info.PrepareCall(name, actualParams); err == nil {
-			result, err = functor.InvokeNamed(ctx, name, actualParams)
-			exportObjectsToParent(ctx)
-		}
-	} else {
-		err = fmt.Errorf("unknown function %s()", name)
-	}
-	return
-}
-
-func GetParam(args map[string]any, paramName string, paramNum int) (value any, exists bool) {
-	if value, exists = args[paramName]; !exists {
-		if paramNum > 0 && paramNum <= len(args) {
-			value, exists = args["arg"+strconv.Itoa(paramNum)]
-		}
-	}
-	return
-}
-
-func bindActualParams(functor Functor, args []any) (actualParams map[string]any) {
-	formalParams := functor.GetParams()
-	actualParams = make(map[string]any, len(args))
-	for i, arg := range args {
-		if i < len(formalParams) {
-			actualParams[formalParams[i].Name()] = arg
-		} else {
-			actualParams["arg"+strconv.Itoa(i+1)] = arg
-		}
-	}
-	return
-}

global-context.go

@@ -1,156 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// global-context.go
-package expr
-
-import (
-	"path/filepath"
-	"strings"
-)
-
-var globalCtx *SimpleStore
-
-func ImportInContext(name string) (exists bool) {
-	var mod *builtinModule
-	if mod, exists = builtinModuleRegister[name]; exists {
-		mod.importFunc(globalCtx)
-		mod.imported = true
-	}
-	return
-}
-
-func ImportInContextByGlobPattern(pattern string) (count int, err error) {
-	var matched bool
-	for name, mod := range builtinModuleRegister {
-		if matched, err = filepath.Match(pattern, name); err == nil {
-			if matched {
-				count++
-				mod.importFunc(globalCtx)
-				mod.imported = true
-			}
-		} else {
-			break
-		}
-	}
-	return
-}
-
-func GetVar(ctx ExprContext, name string) (value any, exists bool) {
-	if value, exists = ctx.GetVar(name); !exists {
-		value, exists = globalCtx.GetVar(name)
-	}
-	return
-}
-
-func GetLocalFuncInfo(ctx ExprContext, name string) (item ExprFunc, exists bool) {
-	var v any
-	if len(name) > 0 {
-		if v, exists = ctx.GetVar(name); exists && isFunctor(v) {
-			f, _ := v.(Functor)
-			item = f.GetFunc()
-		} else {
-			item, exists = ctx.GetFuncInfo(name)
-		}
-	}
-	return
-}
-
-func GetFuncInfo(ctx ExprContext, name string) (item ExprFunc, exists bool) {
-	// if len(name) > 0 {
-	// 	if item, exists = GetLocalFuncInfo(ctx, name); exists {
-	// 		ownerCtx = ctx
-	// 	} else if item, exists = globalCtx.GetFuncInfo(name); exists {
-	// 		ownerCtx = globalCtx
-	// 	}
-	// }
-	item, exists, _ = GetFuncInfoAndOwner(ctx, name)
-	return
-}
-
-func GetFuncInfoAndOwner(ctx ExprContext, name string) (item ExprFunc, exists bool, ownerCtx ExprContext) {
-	if len(name) > 0 {
-		if item, exists = GetLocalFuncInfo(ctx, name); exists {
-			ownerCtx = ctx
-		} else if item, exists = globalCtx.GetFuncInfo(name); exists {
-			ownerCtx = globalCtx
-		}
-	}
-	return
-}
-
-func GlobalCtrlSet(name string, newValue any) (currentValue any) {
-	if !strings.HasPrefix(name, "_") {
-		name = "_" + name
-	}
-	currentValue, _ = globalCtx.GetVar(name)
-
-	globalCtx.SetVar(name, newValue)
-	return currentValue
-}
-
-func GlobalCtrlGet(name string) (currentValue any) {
-	if !strings.HasPrefix(name, "_") {
-		name = "_" + name
-	}
-	currentValue, _ = globalCtx.GetVar(name)
-	return currentValue
-}
-
-func CtrlEnable(ctx ExprContext, name string) (currentStatus bool) {
-	if !strings.HasPrefix(name, "_") {
-		name = "_" + name
-	}
-	if v, exists := ctx.GetVar(name); exists && IsBool(v) {
-		currentStatus, _ = v.(bool)
-	}
-
-	ctx.SetVar(name, true)
-	return currentStatus
-}
-
-func CtrlDisable(ctx ExprContext, name string) (currentStatus bool) {
-	if !strings.HasPrefix(name, "_") {
-		name = "_" + name
-	}
-	if v, exists := ctx.GetVar(name); exists && IsBool(v) {
-		currentStatus, _ = v.(bool)
-	}
-
-	ctx.SetVar(name, false)
-	return currentStatus
-}
-
-func CtrlIsEnabled(ctx ExprContext, name string) (status bool) {
-	var v any
-	var exists bool
-
-	if !strings.HasPrefix(name, "_") {
-		name = "_" + name
-	}
-
-	if v, exists = ctx.GetVar(name); !exists {
-		v, exists = globalCtx.GetVar(name)
-	}
-
-	if exists {
-		if b, ok := v.(bool); ok {
-			status = b
-		}
-	}
-	return
-}
-
-func getControlString(name string) (s string, exists bool) {
-	var v any
-	if v, exists = globalCtx.GetVar(name); exists {
-		s, exists = v.(string)
-	}
-	return
-}
-
-func init() {
-	globalCtx = NewSimpleStore()
-	initDefaultVars(globalCtx)
-	ImportBuiltinsFuncs(globalCtx)
-}

go.mod

@@ -1,7 +1,3 @@
 module git.portale-stac.it/go-pkg/expr
 
-go 1.22.0
+go 1.21.6
-
-toolchain go1.23.3
-
-require golang.org/x/exp v0.0.0-20241204233417-43b7b7cde48d

go.sum

@@ -1,4 +0,0 @@
-github.com/yqylovy/goimportdot v0.0.0-20170519021755-eb181a7eeabe h1:bWYrKmmfv37uNgXTdwkLSKYiYPJ1yfWmjBnvtMyAYzk=
-github.com/yqylovy/goimportdot v0.0.0-20170519021755-eb181a7eeabe/go.mod h1:alTKUpAJ/zbp17qvZwcFNwzufrb5DljMDY4mgJlIHao=
-golang.org/x/exp v0.0.0-20241204233417-43b7b7cde48d h1:0olWaB5pg3+oychR51GUVCEsGkeCU/2JxjBgIo4f3M0=
-golang.org/x/exp v0.0.0-20241204233417-43b7b7cde48d/go.mod h1:qj5a5QZpwLU2NLQudwIN5koi3beDhSAlJwa67PuM98c=

graph_test.go

@@ -1,7 +1,10 @@
 // Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
 // All rights reserved.
 
-// t_graph_test.go
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
+// graph_test.go
 package expr
 
 import (

helpers.go

@@ -6,8 +6,6 @@ package expr
 
 import (
 	"fmt"
-	"io"
-	"os"
 	"strings"
 )
 
@@ -16,10 +14,10 @@ func EvalString(ctx ExprContext, source string) (result any, err error) {
 
 	r := strings.NewReader(source)
 	scanner := NewScanner(r, DefaultTranslations())
-	parser := NewParser()
+	parser := NewParser(ctx)
 
 	if tree, err = parser.Parse(scanner); err == nil {
-		result, err = tree.Eval(ctx)
+		result, err = tree.eval(ctx, true)
 	}
 	return
 }
@@ -34,15 +32,12 @@ func EvalStringA(source string, args ...Arg) (result any, err error) {
 }
 
 func EvalStringV(source string, args []Arg) (result any, err error) {
-	ctx := NewSimpleStore()
+	ctx := NewSimpleFuncStore()
 	for _, arg := range args {
 		if isFunc(arg.Value) {
 			if f, ok := arg.Value.(FuncTemplate); ok {
-				functor := NewGolangFunctor(f)
+				functor := &simpleFunctor{f: f}
-				// ctx.RegisterFunc(arg.Name, functor, 0, -1)
+				ctx.RegisterFunc(arg.Name, functor, 0, -1)
-				ctx.RegisterFunc(arg.Name, functor, TypeAny, []ExprFuncParam{
-					NewFuncParamFlagDef(ParamValue, PfDefault|PfRepeat, 0),
-				})
 			} else {
 				err = fmt.Errorf("invalid function specification: %q", arg.Name)
 			}
@@ -64,24 +59,3 @@ func EvalStringV(source string, args []Arg) (result any, err error) {
 	}
 	return
 }
-
-func EvalStream(ctx ExprContext, r io.Reader) (result any, err error) {
-	var tree *ast
-	scanner := NewScanner(r, DefaultTranslations())
-	parser := NewParser()
-
-	if tree, err = parser.Parse(scanner); err == nil {
-		result, err = tree.Eval(ctx)
-	}
-	return
-}
-
-func EvalFile(ctx ExprContext, filePath string) (result any, err error) {
-	var fh *os.File
-	if fh, err = os.Open(filePath); err != nil {
-		return nil, err
-	}
-	defer fh.Close()
-	result, err = EvalStream(ctx, fh)
-	return
-}

helpers_test.go

@@ -0,0 +1,81 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
+// helpers_test.go
+package expr
+
+import (
+	"fmt"
+	"testing"
+)
+
+func subtract(ctx ExprContext, name string, args []any) (result any, err error) {
+	if len(args) != 2 {
+		err = fmt.Errorf("%s(): requires exactly two arguments", name)
+		return
+	}
+	x, xok := args[0].(int64)
+	y, yok := args[1].(int64)
+	if xok && yok {
+		result = x - y
+	} else {
+		err = fmt.Errorf("expected integer (int64) arguments, got %T and %T values", x, y)
+	}
+	return
+}
+
+func TestEvalStringA(t *testing.T) {
+
+	source := `a + b * subtract(4,2)`
+	args := []Arg{
+		{"a", uint8(1)},
+		{"b", int8(2)},
+		{"subtract", FuncTemplate(subtract)},
+		// force coverage
+		{"a16", uint16(1)},
+		{"b16", int16(2)},
+		{"a32", uint32(1)},
+		{"b32", int32(2)},
+		{"a64", uint64(1)},
+		{"b64", int64(2)},
+		{"f32", float32(1.0)},
+		{"f64", float64(1.0)},
+	}
+
+	wantResult := int64(5)
+	gotResult, gotErr := EvalStringA(source, args...)
+	if value, ok := gotResult.(int64); ok && value != wantResult {
+		t.Errorf("Source %q got %v, want %v", source, gotResult, wantResult)
+		t.Errorf("Error: %v", gotErr)
+	}
+}
+
+func TestEvalString(t *testing.T) {
+
+	ctx := NewSimpleVarStore()
+	ctx.SetVar("a", uint8(1))
+	ctx.SetVar("b", int8(2))
+	ctx.SetVar("f", 2.0)
+	// force coverage
+	ctx.SetVar("a16", uint16(1))
+	ctx.SetVar("b16", int16(2))
+	ctx.SetVar("a32", uint32(1))
+	ctx.SetVar("b32", int32(2))
+	ctx.SetVar("a64", uint64(1))
+	ctx.SetVar("b64", int64(2))
+	ctx.SetVar("f32", float32(1.0))
+	ctx.SetVar("f64", float64(1.0))
+
+	// force coverage
+	ctx.GetFuncInfo("dummy")
+	ctx.Call("dummy", []any{})
+
+	source := `a + b * f`
+
+	wantResult := float64(5)
+	gotResult, gotErr := EvalString(ctx, source)
+	if value, ok := gotResult.(float64); ok && value != wantResult {
+		t.Errorf("Source %q got %v, want %v", source, gotResult, wantResult)
+		t.Errorf("Error: %v", gotErr)
+	}
+}

hook_test.txt

@@ -0,0 +1,3 @@
+First test
+next commit
+nr 3

import-utils.go

@@ -1,112 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// import-utils.go
-package expr
-
-import (
-	"errors"
-	"fmt"
-	"os"
-	"path"
-	"path/filepath"
-	"strings"
-)
-
-const (
-	ENV_EXPR_SOURCE_PATH = "EXPR_PATH"
-	ENV_EXPR_PLUGIN_PATH = "EXPR_PLUGIN_PATH"
-)
-
-func checkStringParamExpected(funcName string, paramValue any, paramPos int) (err error) {
-	if !(IsString(paramValue) /*|| isList(paramValue)*/) {
-		err = fmt.Errorf("%s(): param nr %d has wrong type %s, string expected", funcName, paramPos+1, TypeName(paramValue))
-	}
-	return
-}
-
-// func addSourceEnvImportDirs(varName string, dirList []string) []string {
-// 	return addEnvImportDirs(ENV_EXPR_SOURCE_PATH, dirList)
-// }
-
-// func addPluginEnvImportDirs(varName string, dirList []string) []string {
-// 	return addEnvImportDirs(ENV_EXPR_PLUGIN_PATH, dirList)
-// }
-
-func addEnvImportDirs(envVarName string, dirList []string) []string {
-	if dirSpec, exists := os.LookupEnv(envVarName); exists {
-		dirs := strings.Split(dirSpec, ":")
-		if dirList == nil {
-			dirList = dirs
-		} else {
-			dirList = append(dirList, dirs...)
-		}
-	}
-	return dirList
-}
-
-func addSearchDirs(endingPath string, dirList []string) []string {
-	if dirSpec, exists := getControlString(ControlSearchPath); exists {
-		dirs := strings.Split(dirSpec, ":")
-		if dirList == nil {
-			dirList = dirs
-		} else {
-			if len(endingPath) > 0 {
-				for _, d := range dirs {
-					dirList = append(dirList, path.Join(d, endingPath))
-				}
-			} else {
-				dirList = append(dirList, dirs...)
-			}
-		}
-	}
-	return dirList
-}
-
-func buildSearchDirList(endingPath, envVarName string) (dirList []string) {
-	dirList = addEnvImportDirs(envVarName, dirList)
-	dirList = addSearchDirs(endingPath, dirList)
-	return
-}
-
-func isFile(filePath string) bool {
-	info, err := os.Stat(filePath)
-	return (err == nil || errors.Is(err, os.ErrExist)) && info.Mode().IsRegular()
-}
-
-func searchAmongPath(filename string, dirList []string) (filePath string) {
-	var err error
-	for _, dir := range dirList {
-		if dir, err = ExpandPath(dir); err != nil {
-			continue
-		}
-		if fullPath := path.Join(dir, filename); isFile(fullPath) {
-			filePath = fullPath
-			break
-		}
-	}
-	return
-}
-
-func isPathRelative(filePath string) bool {
-	unixPath := filepath.ToSlash(filePath)
-	return strings.HasPrefix(unixPath, "./") || strings.HasPrefix(unixPath, "../")
-}
-
-func makeFilepath(filename string, dirList []string) (filePath string, err error) {
-	if filename, err = ExpandPath(filename); err != nil {
-		return
-	}
-
-	if path.IsAbs(filename) || isPathRelative(filename) {
-		if isFile(filename) {
-			filePath = filename
-		}
-	} else {
-		filePath = searchAmongPath(filename, dirList)
-	}
-	if len(filePath) == 0 {
-		err = fmt.Errorf("file %q not found", filename)
-	}
-	return
-}

iterator.go

@@ -4,45 +4,37 @@
 // iterator.go
 package expr
 
-import (
+import "io"
-	// "errors"
-	"fmt"
-)
-
-// Operator names
-
-const (
-	InitName    = "init"
-	CleanName   = "clean"
-	ResetName   = "reset"
-	NextName    = "next"
-	CurrentName = "current"
-	IndexName   = "index"
-	CountName   = "count"
-	FilterName  = "filter"
-	MapName     = "map"
-)
 
 type Iterator interface {
-	Typer
+	Reset()
 	Next() (item any, err error) // must return io.EOF after the last item
-	Current() (item any, err error)
 	Index() int
-	Count() int
 }
 
-type ExtIterator interface {
+type FlatArrayIterator struct {
-	Iterator
+	a     []any
-	Reset() error
+	index int
-	Clean() error
-	HasOperation(name string) bool
-	CallOperation(name string, args map[string]any) (value any, err error)
 }
 
-func errNoOperation(name string) error {
+func NewFlatArrayIterator(array []any) *FlatArrayIterator {
-	return fmt.Errorf("no %s() function defined in the data-source", name)
+	return &FlatArrayIterator{a: array, index: 0}
 }
 
-// func errInvalidDataSource() error {
+func (it *FlatArrayIterator) Reset() {
-// 	return errors.New("invalid data-source")
+	it.index = 0
-// }
+}
+
+func (it *FlatArrayIterator) Next() (item any, err error) {
+	if it.index < len(it.a) {
+		item = it.a[it.index]
+		it.index++
+	} else {
+		err = io.EOF
+	}
+	return
+}
+
+func (it *FlatArrayIterator) Index() int {
+	return it.index - 1
+}

list-iterator.go

@@ -1,160 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// list-iterator.go
-package expr
-
-import (
-	"fmt"
-	"io"
-)
-
-type ListIterator struct {
-	a     *ListType
-	count int
-	index int
-	start int
-	stop  int
-	step  int
-}
-
-func NewListIterator(list *ListType, args []any) (it *ListIterator) {
-	var argc int = 0
-	listLen := len(([]any)(*list))
-	if args != nil {
-		argc = len(args)
-	}
-	it = &ListIterator{a: list, count: 0, index: -1, start: 0, stop: listLen - 1, step: 1}
-	if argc >= 1 {
-		if i, err := ToGoInt(args[0], "start index"); err == nil {
-			if i < 0 {
-				i = listLen + i
-			}
-			it.start = i
-		}
-		if argc >= 2 {
-			if i, err := ToGoInt(args[1], "stop index"); err == nil {
-				if i < 0 {
-					i = listLen + i
-				}
-				it.stop = i
-			}
-			if argc >= 3 {
-				if i, err := ToGoInt(args[2], "step"); err == nil {
-					if i < 0 {
-						i = -i
-					}
-					if it.start > it.stop {
-						it.step = -i
-					} else {
-						it.step = i
-					}
-				}
-			}
-		}
-	}
-	it.index = it.start - it.step
-	return
-}
-
-func NewArrayIterator(array []any) (it *ListIterator) {
-	it = &ListIterator{a: (*ListType)(&array), count: 0, index: -1, start: 0, stop: len(array) - 1, step: 1}
-	return
-}
-
-func NewAnyIterator(value any) (it *ListIterator) {
-	if value == nil {
-		it = NewArrayIterator([]any{})
-	} else if list, ok := value.(*ListType); ok {
-		it = NewListIterator(list, nil)
-	} else if array, ok := value.([]any); ok {
-		it = NewArrayIterator(array)
-	} else if it1, ok := value.(*ListIterator); ok {
-		it = it1
-	} else {
-		it = NewArrayIterator([]any{value})
-	}
-	return
-}
-
-func (it *ListIterator) String() string {
-	var l = 0
-	if it.a != nil {
-		l = len(*it.a)
-	}
-	return fmt.Sprintf("$(#%d)", l)
-}
-
-func (it *ListIterator) TypeName() string {
-	return "ListIterator"
-}
-
-func (it *ListIterator) HasOperation(name string) bool {
-	yes := name == NextName || name == ResetName || name == IndexName || name == CountName || name == CurrentName
-	return yes
-}
-
-func (it *ListIterator) CallOperation(name string, args map[string]any) (v any, err error) {
-	switch name {
-	case NextName:
-		v, err = it.Next()
-	case ResetName:
-		err = it.Reset()
-	case CleanName:
-		err = it.Clean()
-	case IndexName:
-		v = int64(it.Index())
-	case CurrentName:
-		v, err = it.Current()
-	case CountName:
-		v = it.count
-	default:
-		err = errNoOperation(name)
-	}
-	return
-}
-
-func (it *ListIterator) Current() (item any, err error) {
-	a := *(it.a)
-	if it.start <= it.stop {
-		if it.stop < len(a) && it.index >= it.start && it.index <= it.stop {
-			item = a[it.index]
-		} else {
-			err = io.EOF
-		}
-	} else {
-		if it.start < len(a) && it.index >= it.stop && it.index <= it.start {
-			item = a[it.index]
-		} else {
-			err = io.EOF
-		}
-
-	}
-	return
-}
-
-func (it *ListIterator) Next() (item any, err error) {
-	it.index += it.step
-	if item, err = it.Current(); err != io.EOF {
-		it.count++
-	}
-	return
-}
-
-func (it *ListIterator) Index() int {
-	return it.index
-}
-
-func (it *ListIterator) Count() int {
-	return it.count
-}
-
-func (it *ListIterator) Reset() (error) {
-	it.index = it.start - it.step
-	it.count = 0
-	return nil
-}
-
-func (it *ListIterator) Clean() (error) {
-	return nil
-}

list-type.go

@@ -1,195 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// list-type.go
-package expr
-
-import (
-	"fmt"
-	"reflect"
-	"strings"
-)
-
-type ListType []any
-
-func newListA(listAny ...any) (list *ListType) {
-	if listAny == nil {
-		listAny = []any{}
-	}
-	return newList(listAny)
-}
-
-func newList(listAny []any) (list *ListType) {
-	return NewList(listAny)
-}
-
-func NewList(listAny []any) (list *ListType) {
-	if listAny != nil {
-		ls := make(ListType, len(listAny))
-//		for i, item := range listAny {
-//			ls[i] = item
-//		}
-		copy(ls, listAny)
-		list = &ls
-	}
-	return
-}
-
-func MakeList(length, capacity int) (list *ListType) {
-	if capacity < length {
-		capacity = length
-	}
-	ls := make(ListType, length, capacity)
-	list = &ls
-	return
-}
-
-func ListFromStrings(stringList []string) (list *ListType) {
-	list = MakeList(len(stringList), 0)
-	for i, s := range stringList {
-		(*list)[i] = s
-	}
-	return
-}
-
-func (ls *ListType) ToString(opt FmtOpt) (s string) {
-        indent := GetFormatIndent(opt)
-        flags := GetFormatFlags(opt)
-
-	var sb strings.Builder
-	sb.WriteByte('[')
-	if len(*ls) > 0 {
-                innerOpt := MakeFormatOptions(flags, indent+1)
-                nest := strings.Repeat("  ", indent+1)
-
-		if flags&MultiLine != 0 {
-			sb.WriteByte('\n')
-			sb.WriteString(nest)
-		}
-		for i, item := range []any(*ls) {
-			if i > 0 {
-				if flags&MultiLine != 0 {
-					sb.WriteString(",\n")
-					sb.WriteString(nest)
-				} else {
-					sb.WriteString(", ")
-				}
-			}
-			if s, ok := item.(string); ok {
-				sb.WriteByte('"')
-				sb.WriteString(s)
-				sb.WriteByte('"')
-			} else if formatter, ok := item.(Formatter); ok {
-				sb.WriteString(formatter.ToString(innerOpt))
-			} else {
-				sb.WriteString(fmt.Sprintf("%v", item))
-			}
-		}
-		if flags&MultiLine != 0 {
-			sb.WriteByte('\n')
-			sb.WriteString(strings.Repeat("  ", indent))
-		}
-	}
-	sb.WriteByte(']')
-	s = sb.String()
-	if flags&Truncate != 0 && len(s) > TruncateSize {
-		s = TruncateString(s)
-	}
-	return
-}
-
-func (ls *ListType) String() string {
-	return ls.ToString(0)
-}
-
-func (ls *ListType) TypeName() string {
-	return "list"
-}
-
-// func (list *ListType) indexDeepCmp(target any) (index int) {
-// 	index = -1
-// 	for i, item := range *list {
-// 		if reflect.DeepEqual(item, target) {
-// 			index = i
-// 			break
-// 		}
-// 	}
-// 	return
-// }
-
-func (ls *ListType) contains(t *ListType) (answer bool) {
-	if len(*ls) >= len(*t) {
-		answer = true
-		for _, item := range *t {
-			if answer = ls.indexDeepSameCmp(item) >= 0; !answer {
-				break
-			}
-		}
-	}
-	return
-}
-
-func (list *ListType) indexDeepSameCmp(target any) (index int) {
-	var eq bool
-	var err error
-	index = -1
-	for i, item := range *list {
-		if eq, err = deepSame(item, target, sameContent); err != nil {
-			break
-		} else if eq {
-			index = i
-			break
-		}
-	}
-	return
-}
-
-func sameContent(a, b any) (same bool, err error) {
-	la, _ := a.(*ListType)
-	lb, _ := b.(*ListType)
-	if len(*la) == len(*lb) {
-		same = true
-		for _, item := range *la {
-			if pos := lb.indexDeepSameCmp(item); pos < 0 {
-				same = false
-				break
-			}
-		}
-	}
-	return
-}
-
-func deepSame(a, b any, deepCmp deepFuncTemplate) (eq bool, err error) {
-	if isNumOrFract(a) && isNumOrFract(b) {
-		if IsNumber(a) && IsNumber(b) {
-			if IsInteger(a) && IsInteger(b) {
-				li, _ := a.(int64)
-				ri, _ := b.(int64)
-				eq = li == ri
-			} else {
-				eq = numAsFloat(a) == numAsFloat(b)
-			}
-		} else {
-			var cmp int
-			if cmp, err = cmpAnyFract(a, b); err == nil {
-				eq = cmp == 0
-			}
-		}
-	} else if deepCmp != nil && IsList(a) && IsList(b) {
-		eq, err = deepCmp(a, b)
-	} else {
-		eq = reflect.DeepEqual(a, b)
-	}
-
-	return
-}
-
-func (list *ListType) setItem(index int64, value any) (err error) {
-	if index >= 0 && index < int64(len(*list)) {
-		(*list)[index] = value
-	} else {
-		err = fmt.Errorf("index %d out of bounds (0, %d)", index, len(*list)-1)
-	}
-	return
-}
-

operand-const.go

@@ -0,0 +1,73 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
+// operand-const.go
+package expr
+
+// -------- bool const term
+func newBoolTerm(tk *Token) *term {
+	return &term{
+		tk: *tk,
+		// class:    classConst,
+		// kind:     kindBool,
+		parent:   nil,
+		children: nil,
+		position: posLeaf,
+		priority: priValue,
+		evalFunc: evalConst,
+	}
+}
+
+// -------- integer const term
+func newIntegerTerm(tk *Token) *term {
+	return &term{
+		tk:       *tk,
+		parent:   nil,
+		children: nil,
+		position: posLeaf,
+		priority: priValue,
+		evalFunc: evalConst,
+	}
+}
+
+// -------- float const term
+func newFloatTerm(tk *Token) *term {
+	return &term{
+		tk: *tk,
+		// class:    classConst,
+		// kind:     kindFloat,
+		parent:   nil,
+		children: nil,
+		position: posLeaf,
+		priority: priValue,
+		evalFunc: evalConst,
+	}
+}
+
+// -------- string const term
+func newStringTerm(tk *Token) *term {
+	return &term{
+		tk: *tk,
+		// class:    classConst,
+		// kind:     kindString,
+		parent:   nil,
+		children: nil,
+		position: posLeaf,
+		priority: priValue,
+		evalFunc: evalConst,
+	}
+}
+
+// -------- eval func
+func evalConst(ctx ExprContext, self *term) (v any, err error) {
+	v = self.tk.Value
+	return
+}
+
+// init
+func init() {
+	registerTermConstructor(SymString, newStringTerm)
+	registerTermConstructor(SymInteger, newIntegerTerm)
+	registerTermConstructor(SymFloat, newFloatTerm)
+	registerTermConstructor(SymBool, newBoolTerm)
+}

operand-dict.go

@@ -1,35 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// operand-dict.go
-package expr
-
-
-// -------- dict term
-func newDictTerm(args map[any]*term) *term {
-	return &term{
-		tk:       *NewValueToken(0, 0, SymDict, "{}", args),
-		parent:   nil,
-		children: nil,
-		position: posLeaf,
-		priority: priValue,
-		evalFunc: evalDict,
-	}
-}
-
-// -------- dict func
-func evalDict(ctx ExprContext, opTerm *term) (v any, err error) {
-	dict, _ := opTerm.value().(map[any]*term)
-	items := make(DictType, len(dict))
-	for key, tree := range dict {
-		var param any
-		if param, err = tree.compute(ctx); err != nil {
-			break
-		}
-		items[key] = param
-	}
-	if err == nil {
-		v = &items
-	}
-	return
-}

operand-expr.go

@@ -7,8 +7,7 @@ package expr
 import "fmt"
 
 // -------- expr term
-func newExprTerm(root *term) *term {
+func newExprTerm(tk *Token) *term {
-	tk := NewValueToken(root.tk.row, root.tk.col, SymExpression, root.source(), root)
 	return &term{
 		tk:       *tk,
 		parent:   nil,
@@ -20,11 +19,16 @@ func newExprTerm(root *term) *term {
 }
 
 // -------- eval expr
-func evalExpr(ctx ExprContext, opTerm *term) (v any, err error) {
+func evalExpr(ctx ExprContext, self *term) (v any, err error) {
-	if expr, ok := opTerm.value().(*term); ok {
+	if expr, ok := self.value().(Expr); ok {
-		v, err = expr.compute(ctx)
+		v, err = expr.eval(ctx, false)
 	} else {
-		err = fmt.Errorf("expression expected, got %T", opTerm.value())
+		err = fmt.Errorf("expression expected, got %T", self.value())
 	}
 	return
 }
+
+// init
+// func init() {
+// 	registerTermConstructor(SymExpression, newExprTerm)
+// }

operand-func.go

@@ -12,6 +12,8 @@ import (
 func newFuncCallTerm(tk *Token, args []*term) *term {
 	return &term{
 		tk: *tk,
+		// class:    classVar,
+		// kind:     kindUnknown,
 		parent:   nil,
 		children: args,
 		position: posLeaf,
@@ -21,35 +23,56 @@ func newFuncCallTerm(tk *Token, args []*term) *term {
 }
 
 // -------- eval func call
-// func _evalFuncCall(ctx ExprContext, opTerm *term) (v any, err error) {
+func evalFuncCall(parentCtx ExprContext, self *term) (v any, err error) {
-// 	name, _ := opTerm.tk.Value.(string)
+	ctx := parentCtx.Clone()
-// 	params := make([]any, len(opTerm.children), len(opTerm.children)+5)
+	name, _ := self.tk.Value.(string)
-// 	for i, tree := range opTerm.children {
+	params := make([]any, len(self.children))
-// 		var param any
+	for i, tree := range self.children {
-// 		if param, err = tree.compute(ctx); err != nil {
+		var param any
-// 			break
+		if param, err = tree.compute(ctx); err != nil {
-// 		}
+			break
-// 		params[i] = param
+		}
-// 	}
+		params[i] = param
-
+	}
-// 	if err == nil {
+	if err == nil {
-// 		v, err = CallFunction(ctx, name, params)
+		if v, err = ctx.Call(name, params); err == nil {
-// 	}
+			exportAll := isEnabled(ctx, control_export_all)
-// 	return
+			// Export variables
-// }
+			for _, refName := range ctx.EnumVars(func(name string) bool { return exportAll || name[0] == '@' }) {
-
+				refValue, _ := ctx.GetVar(refName)
-func evalFuncCall(ctx ExprContext, opTerm *term) (v any, err error) {
+				exportVar(parentCtx, refName, refValue)
-	name, _ := opTerm.tk.Value.(string)
+			}
-	v, err = CallFunctionByTerm(ctx, name, opTerm)
+			// Export functions
+			for _, refName := range ctx.EnumFuncs(func(name string) bool { return exportAll || name[0] == '@' }) {
+				if info := ctx.GetFuncInfo(refName); info != nil {
+					exportFunc(parentCtx, refName, info)
+				}
+			}
+		}
+	}
 	return
 }
 
+func exportVar(ctx ExprContext, name string, value any) {
+	if name[0] == '@' {
+		name = name[1:]
+	}
+	ctx.setVar(name, value)
+}
+
+func exportFunc(ctx ExprContext, name string, info ExprFunc) {
+	if name[0] == '@' {
+		name = name[1:]
+	}
+	ctx.RegisterFunc(name, info.Functor(), info.MinArgs(), info.MaxArgs())
+}
+
 // -------- function definition term
 func newFuncDefTerm(tk *Token, args []*term) *term {
 	return &term{
-		tk:       *tk, // value is the expression body
+		tk:       *tk,
 		parent:   nil,
-		children: args, // function params
+		children: args, // arg[0]=formal-param-list, arg[1]=*ast
 		position: posLeaf,
 		priority: priValue,
 		evalFunc: evalFuncDef,
@@ -57,23 +80,46 @@ func newFuncDefTerm(tk *Token, args []*term) *term {
 }
 
 // -------- eval func def
-func evalFuncDef(ctx ExprContext, opTerm *term) (v any, err error) {
+// TODO
-	bodySpec := opTerm.value()
+type funcDefFunctor struct {
-	if expr, ok := bodySpec.(*ast); ok {
+	params []string
-		paramList := make([]ExprFuncParam, 0, len(opTerm.children))
+	expr   Expr
-		for _, param := range opTerm.children {
+}
-			var defValue any
+
-			flags := paramFlags(0)
+func (functor *funcDefFunctor) Invoke(ctx ExprContext, name string, args []any) (result any, err error) {
-			if len(param.children) > 0 {
+	for i, p := range functor.params {
-				flags |= PfDefault
+		if i < len(args) {
-				if defValue, err = param.children[0].compute(ctx); err != nil {
+			arg := args[i]
+			if functor, ok := arg.(Functor); ok {
+				ctx.RegisterFunc(p, functor, 0, -1)
+			} else {
+				ctx.setVar(p, arg)
+			}
+		} else {
+			ctx.setVar(p, nil)
+		}
+	}
+	result, err = functor.expr.eval(ctx, false)
 	return
+}
+
+func evalFuncDef(ctx ExprContext, self *term) (v any, err error) {
+	bodySpec := self.value()
+	if expr, ok := bodySpec.(*ast); ok {
+		paramList := make([]string, 0, len(self.children))
+		for _, param := range self.children {
+			paramList = append(paramList, param.source())
+			// if paramName, ok := param.value().(string); ok {
+			// 	paramList = append(paramList, paramName)
+			// } else {
+			// 	err = fmt.Errorf("invalid function definition: formal param nr %d must be an identifier", i+1)
+			// 	break
+			// }
 		}
+		v = &funcDefFunctor{
+			params: paramList,
+			expr:   expr,
 		}
-			info := NewFuncParamFlagDef(param.source(), flags, defValue)
-			paramList = append(paramList, info)
-		}
-		v = newExprFunctor(expr, paramList, ctx)
 	} else {
 		err = errors.New("invalid function definition: the body specification must be an expression")
 	}

operand-iterator.go

@@ -1,152 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// operand-iterator.go
-package expr
-
-import (
-	"slices"
-	"strings"
-)
-
-// -------- iterator term
-
-func newIteratorTerm(tk *Token, args []*term) *term {
-	tk.Sym = SymIterator
-	return &term{
-		tk:       *tk,
-		parent:   nil,
-		children: args,
-		position: posLeaf,
-		priority: priValue,
-		evalFunc: evalIterator,
-	}
-}
-
-// -------- eval iterator
-
-func evalTermArray(ctx ExprContext, terms []*term) (values []any, err error) {
-	values = make([]any, len(terms))
-	for i, t := range terms {
-		var value any
-		if value, err = t.compute(ctx); err == nil {
-			values[i] = value
-		} else {
-			break
-		}
-	}
-	return
-}
-
-func evalFirstChild(ctx ExprContext, iteratorTerm *term) (value any, err error) {
-	if len(iteratorTerm.children) < 1 || iteratorTerm.children[0] == nil {
-		err = iteratorTerm.Errorf("missing the data-source parameter")
-		return
-	}
-
-	value, err = iteratorTerm.children[0].compute(ctx)
-	return
-}
-
-func getDataSourceDict(iteratorTerm *term, firstChildValue any) (ds map[string]Functor, err error) {
-	if dictAny, ok := firstChildValue.(*DictType); ok {
-		requiredFields := []string{NextName}
-		fieldsMask := 0b1
-		foundFields := 0
-		ds = make(map[string]Functor)
-		for keyAny, item := range *dictAny {
-			if key, ok := keyAny.(string); ok {
-				if functor, ok := item.(Functor); ok {
-					ds[key] = functor
-					if index := slices.Index(requiredFields, key); index >= 0 {
-						foundFields |= 1 << index
-					}
-				}
-			}
-		}
-		// check required functions
-		if foundFields != fieldsMask {
-			missingFields := make([]string, 0, len(requiredFields))
-			for index, field := range requiredFields {
-				if (foundFields & (1 << index)) == 0 {
-					missingFields = append(missingFields, field)
-				}
-			}
-			err = iteratorTerm.children[0].Errorf("the data-source must provide a non-nil %q operator(s)", strings.Join(missingFields, ", "))
-		}
-	}
-	return
-}
-
-func evalIterator(ctx ExprContext, opTerm *term) (v any, err error) {
-	var firstChildValue any
-	var ds map[string]Functor
-
-	if firstChildValue, err = evalFirstChild(ctx, opTerm); err != nil {
-		return
-	}
-
-	if ds, err = getDataSourceDict(opTerm, firstChildValue); err != nil {
-		return
-	}
-
-	if ds != nil {
-		var dc *dataCursor
-		dcCtx := ctx.Clone()
-		if initFunc, exists := ds[InitName]; exists && initFunc != nil {
-			var args []any
-			var resource any
-			if len(opTerm.children) > 1 {
-				if args, err = evalTermArray(ctx, opTerm.children[1:]); err != nil {
-					return
-				}
-			} else {
-				args = []any{}
-			}
-
-			actualParams := bindActualParams(initFunc, args)
-
-			initCtx := ctx.Clone()
-			if resource, err = initFunc.InvokeNamed(initCtx, InitName, actualParams); err != nil {
-				return
-			}
-			exportObjects(dcCtx, initCtx)
-			dc = NewDataCursor(dcCtx, ds, resource)
-		} else {
-			dc = NewDataCursor(dcCtx, ds, nil)
-		}
-
-		v = dc
-	} else if list, ok := firstChildValue.(*ListType); ok {
-		var args []any
-		if args, err = evalSibling(ctx, opTerm.children, nil); err == nil {
-			v = NewListIterator(list, args)
-		}
-	} else {
-		var list []any
-		if list, err = evalSibling(ctx, opTerm.children, firstChildValue); err == nil {
-			v = NewArrayIterator(list)
-		}
-	}
-	return
-}
-
-func evalSibling(ctx ExprContext, terms []*term, firstChildValue any) (list []any, err error) {
-	items := make([]any, 0, len(terms))
-	for i, tree := range terms {
-		var param any
-		if i == 0 {
-			if firstChildValue == nil {
-				continue
-			}
-			param = firstChildValue
-		} else if param, err = tree.compute(ctx); err != nil {
-			break
-		}
-		items = append(items, param)
-	}
-	if err == nil {
-		list = items
-	}
-	return
-}

operand-list.go

@@ -6,12 +6,12 @@ package expr
 
 // -------- list term
 func newListTermA(args ...*term) *term {
-	return newListTerm(0, 0, args)
+	return newListTerm(args)
 }
 
-func newListTerm(row, col int, args []*term) *term {
+func newListTerm(args []*term) *term {
 	return &term{
-		tk:       *NewValueToken(row, col, SymList, "[]", args),
+		tk:       *NewValueToken(0, 0, SymList, "[]", args),
 		parent:   nil,
 		children: nil,
 		position: posLeaf,
@@ -21,9 +21,9 @@ func newListTerm(row, col int, args []*term) *term {
 }
 
 // -------- list func
-func evalList(ctx ExprContext, opTerm *term) (v any, err error) {
+func evalList(ctx ExprContext, self *term) (v any, err error) {
-	list, _ := opTerm.value().([]*term)
+	list, _ := self.value().([]*term)
-	items := make(ListType, len(list))
+	items := make([]any, len(list))
 	for i, tree := range list {
 		var param any
 		if param, err = tree.compute(ctx); err != nil {
@@ -32,7 +32,35 @@ func evalList(ctx ExprContext, opTerm *term) (v any, err error) {
 		items[i] = param
 	}
 	if err == nil {
-		v = &items
+		v = items
 	}
 	return
 }
+
+// // -------- list term
+// func newListTerm(args []*term) *term {
+// 	return &term{
+// 		tk:       *NewToken(0, 0, SymList, "[]"),
+// 		parent:   nil,
+// 		children: args,
+// 		position: posLeaf,
+// 		priority: priValue,
+// 		evalFunc: evalList,
+// 	}
+// }
+
+// // -------- list func
+// func evalList(ctx ExprContext, self *term) (v any, err error) {
+// 	items := make([]any, len(self.children))
+// 	for i, tree := range self.children {
+// 		var param any
+// 		if param, err = tree.compute(ctx); err != nil {
+// 			break
+// 		}
+// 		items[i] = param
+// 	}
+// 	if err == nil {
+// 		v = items
+// 	}
+// 	return
+// }

operand-literal.go

@@ -1,33 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// operand-literal.go
-package expr
-
-// -------- literal term
-func newLiteralTerm(tk *Token) *term {
-	return &term{
-		tk:       *tk,
-		parent:   nil,
-		children: nil,
-		position: posLeaf,
-		priority: priValue,
-		evalFunc: evalLiteral,
-	}
-}
-
-// -------- eval func
-func evalLiteral(ctx ExprContext, opTerm *term) (v any, err error) {
-	v = opTerm.tk.Value
-	return
-}
-
-// init
-func init() {
-	registerTermConstructor(SymString, newLiteralTerm)
-	registerTermConstructor(SymInteger, newLiteralTerm)
-	registerTermConstructor(SymFloat, newLiteralTerm)
-	registerTermConstructor(SymFraction, newLiteralTerm)
-	registerTermConstructor(SymBool, newLiteralTerm)
-	registerTermConstructor(SymKwNil, newLiteralTerm)
-}

operand-selector-case.go

@@ -41,10 +41,10 @@ func newSelectorCaseTerm(row, col int, filterList *term, caseExpr Expr) *term {
 }
 
 // -------- eval selector case
-func evalSelectorCase(ctx ExprContext, opTerm *term) (v any, err error) {
+func evalSelectorCase(ctx ExprContext, self *term) (v any, err error) {
 	var ok bool
-	if v, ok = opTerm.value().(*selectorCase); !ok {
+	if v, ok = self.value().(*selectorCase); !ok {
-		err = fmt.Errorf("selector-case expected, got %T", opTerm.value())
+		err = fmt.Errorf("selector-case expected, got %T", self.value())
 	}
 	return
 }

operand-var.go

@@ -8,28 +8,23 @@ import "fmt"
 
 // -------- variable term
 func newVarTerm(tk *Token) *term {
-	t := &term{
+	return &term{
 		tk: *tk,
+		// class:    classVar,
+		// kind:     kindUnknown,
 		parent:   nil,
 		children: nil,
 		position: posLeaf,
 		priority: priValue,
 		evalFunc: evalVar,
 	}
-	t.tk.Sym = SymVariable
-	return t
 }
 
 // -------- eval func
-func evalVar(ctx ExprContext, opTerm *term) (v any, err error) {
+func evalVar(ctx ExprContext, self *term) (v any, err error) {
 	var exists bool
-	name := opTerm.source()
+	if v, exists = ctx.GetVar(self.tk.source); !exists {
-	if v, exists = GetVar(ctx, name); !exists {
+		err = fmt.Errorf("undefined variable %q", self.tk.source)
-		if info, exists := GetFuncInfo(ctx, name); exists {
-			v = info.Functor()
-		} else {
-			err = fmt.Errorf("undefined variable or function %q", name)
-		}
 	}
 	return
 }

operator-assign.go

@@ -1,5 +1,5 @@
 // Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserightChilded.
+// All rights reserved.
 
 // operator-assign.go
 package expr
@@ -16,189 +16,22 @@ func newAssignTerm(tk *Token) (inst *term) {
 	}
 }
 
-func assignCollectionItem(ctx ExprContext, collectionTerm, keyListTerm *term, value any) (err error) {
+func evalAssign(ctx ExprContext, self *term) (v any, err error) {
-	var collectionValue, keyListValue, keyValue any
+	if err = self.checkOperands(); err != nil {
-	var keyList *ListType
-	var ok bool
-
-	if collectionValue, err = collectionTerm.compute(ctx); err != nil {
 		return
 	}
 
-	if keyListValue, err = keyListTerm.compute(ctx); err != nil {
+	leftTerm := self.children[0]
-		return
+	if leftTerm.tk.Sym != SymIdentifier {
-	} else if keyList, ok = keyListValue.(*ListType); !ok || len(*keyList) != 1 {
+		err = leftTerm.tk.Errorf("left operand of %q must be a variable", self.tk.source)
-		err = keyListTerm.Errorf("index/key specification expected, got %v [%s]", keyListValue, TypeName(keyListValue))
-		return
-	}
-	if keyValue = (*keyList)[0]; keyValue == nil {
-		err = keyListTerm.Errorf("index/key is nil")
 		return
 	}
 
-	switch collection := collectionValue.(type) {
+	if v, err = self.children[1].compute(ctx); err == nil {
-	case *ListType:
-		if index, ok := keyValue.(int64); ok {
-			err = collection.setItem(index, value)
-		} else {
-			err = keyListTerm.Errorf("integer expected, got %v [%s]", keyValue, TypeName(keyValue))
-		}
-	case *DictType:
-		err = collection.setItem(keyValue, value)
-	default:
-		err = collectionTerm.Errorf("collection expected")
-	}
-	return
-}
-
-func assignValue(ctx ExprContext, leftTerm *term, v any) (err error) {
-	if leftTerm.symbol() == SymIndex {
-		err = assignCollectionItem(ctx, leftTerm.children[0], leftTerm.children[1], v)
-	} else {
-		ctx.UnsafeSetVar(leftTerm.source(), v)
-	}
-	return
-}
-
-func evalAssign(ctx ExprContext, opTerm *term) (v any, err error) {
-	if err = opTerm.checkOperands(); err != nil {
-		return
-	}
-
-	leftTerm := opTerm.children[0]
-	leftSym := leftTerm.symbol()
-	if leftSym != SymVariable && leftSym != SymIndex {
-		err = leftTerm.tk.Errorf("left operand of %q must be a variable or a collection's item", opTerm.tk.source)
-		return
-	}
-
-	rightChild := opTerm.children[1]
-
-	if v, err = rightChild.compute(ctx); err == nil {
 		if functor, ok := v.(Functor); ok {
-			if leftSym == SymVariable {
+			ctx.RegisterFunc(leftTerm.source(), functor, 0, -1)
-				if info := functor.GetFunc(); info != nil {
-					ctx.RegisterFunc(leftTerm.source(), info.Functor(), info.ReturnType(), info.Params())
-				} else if funcDef, ok := functor.(*exprFunctor); ok {
-					paramSpecs := ForAll(funcDef.params, func(p ExprFuncParam) ExprFuncParam { return p })
-
-					ctx.RegisterFunc(leftTerm.source(), functor, TypeAny, paramSpecs)
 		} else {
-					err = opTerm.Errorf("unknown function %s()", rightChild.source())
+			ctx.setVar(leftTerm.tk.source, v)
-				}
-			} else {
-				err = assignValue(ctx, leftTerm, v)
-			}
-		} else {
-			err = assignValue(ctx, leftTerm, v)
-		}
-	}
-	if err != nil {
-		v = nil
-	}
-	return
-}
-
-//-------- assign term
-
-func newOpAssignTerm(tk *Token) (inst *term) {
-	return &term{
-		tk:       *tk,
-		children: make([]*term, 0, 2),
-		position: posInfix,
-		priority: priAssign,
-		evalFunc: evalOpAssign,
-	}
-}
-
-func getCollectionItemValue(ctx ExprContext, collectionTerm, keyListTerm *term) (value any, err error) {
-	var collectionValue, keyListValue, keyValue any
-	var keyList *ListType
-	var ok bool
-
-	if collectionValue, err = collectionTerm.compute(ctx); err != nil {
-		return
-	}
-
-	if keyListValue, err = keyListTerm.compute(ctx); err != nil {
-		return
-	} else if keyList, ok = keyListValue.(*ListType); !ok || len(*keyList) != 1 {
-		err = keyListTerm.Errorf("index/key specification expected, got %v [%s]", keyListValue, TypeName(keyListValue))
-		return
-	}
-	if keyValue = (*keyList)[0]; keyValue == nil {
-		err = keyListTerm.Errorf("index/key is nil")
-		return
-	}
-
-	switch collection := collectionValue.(type) {
-	case *ListType:
-		if index, ok := keyValue.(int64); ok {
-			value = (*collection)[index]
-		} else {
-			err = keyListTerm.Errorf("integer expected, got %v [%s]", keyValue, TypeName(keyValue))
-		}
-	case *DictType:
-		value = (*collection)[keyValue]
-	default:
-		err = collectionTerm.Errorf("collection expected")
-	}
-	return
-}
-
-func getAssignValue(ctx ExprContext, leftTerm *term) (value any, err error) {
-	if leftTerm.symbol() == SymIndex {
-		value, err = getCollectionItemValue(ctx, leftTerm.children[0], leftTerm.children[1])
-	} else {
-		value, _ = ctx.GetVar(leftTerm.source())
-	}
-	return
-}
-
-func evalOpAssign(ctx ExprContext, opTerm *term) (v any, err error) {
-	var rightValue, leftValue any
-	if err = opTerm.checkOperands(); err != nil {
-		return
-	}
-
-	leftTerm := opTerm.children[0]
-	leftSym := leftTerm.symbol()
-	if leftSym != SymVariable && leftSym != SymIndex {
-		err = leftTerm.tk.Errorf("left operand of %q must be a variable or a collection's item", opTerm.tk.source)
-		return
-	}
-
-	rightChild := opTerm.children[1]
-
-	if rightValue, err = rightChild.compute(ctx); err == nil {
-		if leftValue, err = getAssignValue(ctx, leftTerm); err == nil {
-			switch opTerm.symbol() {
-			case SymPlusEqual:
-				v, err = sumValues(opTerm, leftValue, rightValue)
-			case SymMinusEqual:
-				v, err = diffValues(opTerm, leftValue, rightValue)
-			case SymStarEqual:
-				v, err = mulValues(opTerm, leftValue, rightValue)
-			case SymSlashEqual:
-				v, err = divValues(opTerm, leftValue, rightValue)
-			case SymPercEqual:
-				v, err = remainderValues(opTerm, leftValue, rightValue)
-			case SymAmpersandEqual:
-				v, err = bitwiseAnd(opTerm, leftValue, rightValue)
-			case SymVertBarEqual:
-				v, err = bitwiseOr(opTerm, leftValue, rightValue)
-			case SymCaretEqual:
-				v, err = bitwiseXor(opTerm, leftValue, rightValue)
-			case SymDoubleLessEqual:
-				v, err = bitLeftShift(opTerm, leftValue, rightValue)
-			case SymDoubleGreaterEqual:
-				v, err = bitRightShift(opTerm, leftValue, rightValue)
-			default:
-				err = opTerm.Errorf("unsupported assign operator %q", opTerm.source())
-			}
-			if err == nil {
-				err = assignValue(ctx, leftTerm, v)
-			}
 		}
 	}
 	return
@@ -207,14 +40,4 @@ func evalOpAssign(ctx ExprContext, opTerm *term) (v any, err error) {
 // init
 func init() {
 	registerTermConstructor(SymEqual, newAssignTerm)
-	registerTermConstructor(SymPlusEqual, newOpAssignTerm)
-	registerTermConstructor(SymMinusEqual, newOpAssignTerm)
-	registerTermConstructor(SymStarEqual, newOpAssignTerm)
-	registerTermConstructor(SymSlashEqual, newOpAssignTerm)
-	registerTermConstructor(SymPercEqual, newOpAssignTerm)
-	registerTermConstructor(SymDoubleLessEqual, newOpAssignTerm)
-	registerTermConstructor(SymDoubleGreaterEqual, newOpAssignTerm)
-	registerTermConstructor(SymAmpersandEqual, newOpAssignTerm)
-	registerTermConstructor(SymVertBarEqual, newOpAssignTerm)
-	registerTermConstructor(SymCaretEqual, newOpAssignTerm)
 }

operator-bitwise.go

@@ -1,154 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// operator-bitwise.go
-package expr
-
-//-------- Bitwise NOT term
-
-func newBitwiseNotTerm(tk *Token) (inst *term) {
-	return &term{
-		tk:       *tk,
-		children: make([]*term, 0, 1),
-		position: posPrefix,
-		priority: priBitwiseNot,
-		evalFunc: evalBitwiseNot,
-	}
-}
-
-func evalBitwiseNot(ctx ExprContext, opTerm *term) (v any, err error) {
-	var value any
-
-	if value, err = opTerm.evalPrefix(ctx); err != nil {
-		return
-	}
-
-	if IsInteger(value) {
-		i, _ := value.(int64)
-		v = ^i
-	} else {
-		err = opTerm.errIncompatibleType(value)
-	}
-	return
-}
-
-//-------- Bitwise AND term
-
-func newBitwiseAndTerm(tk *Token) (inst *term) {
-	return &term{
-		tk:       *tk,
-		children: make([]*term, 0, 2),
-		position: posInfix,
-		priority: priBitwiseAnd,
-		evalFunc: evalBitwiseAnd,
-	}
-}
-
-func bitwiseAnd(opTerm *term, leftValue, rightValue any) (v any, err error) {
-	var leftInt, rightInt int64
-	var lok, rok bool
-
-	leftInt, lok = leftValue.(int64)
-	rightInt, rok = rightValue.(int64)
-
-	if lok && rok {
-		v = leftInt & rightInt
-	} else {
-		err = opTerm.errIncompatibleTypes(leftValue, rightValue)
-	}
-	return
-}
-
-func evalBitwiseAnd(ctx ExprContext, opTerm *term) (v any, err error) {
-	var leftValue, rightValue any
-
-	if leftValue, rightValue, err = opTerm.evalInfix(ctx); err != nil {
-		return
-	}
-	v, err = bitwiseAnd(opTerm, leftValue, rightValue)
-	return
-}
-
-//-------- Bitwise OR term
-
-func newBitwiseOrTerm(tk *Token) (inst *term) {
-	return &term{
-		tk:       *tk,
-		children: make([]*term, 0, 2),
-		position: posInfix,
-		priority: priBitwiseOr,
-		evalFunc: evalBitwiseOr,
-	}
-}
-
-func bitwiseOr(opTerm *term, leftValue, rightValue any) (v any, err error) {
-	var leftInt, rightInt int64
-	var lok, rok bool
-
-	leftInt, lok = leftValue.(int64)
-	rightInt, rok = rightValue.(int64)
-
-	if lok && rok {
-		v = leftInt | rightInt
-	} else {
-		err = opTerm.errIncompatibleTypes(leftValue, rightValue)
-	}
-	return
-}
-
-func evalBitwiseOr(ctx ExprContext, opTerm *term) (v any, err error) {
-	var leftValue, rightValue any
-
-	if leftValue, rightValue, err = opTerm.evalInfix(ctx); err != nil {
-		return
-	}
-
-	v, err = bitwiseOr(opTerm, leftValue, rightValue)
-	return
-}
-
-//-------- Bitwise XOR term
-
-func newBitwiseXorTerm(tk *Token) (inst *term) {
-	return &term{
-		tk:       *tk,
-		children: make([]*term, 0, 2),
-		position: posInfix,
-		priority: priBitwiseOr,
-		evalFunc: evalBitwiseXor,
-	}
-}
-
-func bitwiseXor(opTerm *term, leftValue, rightValue any) (v any, err error) {
-	var leftInt, rightInt int64
-	var lok, rok bool
-
-	leftInt, lok = leftValue.(int64)
-	rightInt, rok = rightValue.(int64)
-
-	if lok && rok {
-		v = leftInt ^ rightInt
-	} else {
-		err = opTerm.errIncompatibleTypes(leftValue, rightValue)
-	}
-	return
-}
-
-func evalBitwiseXor(ctx ExprContext, opTerm *term) (v any, err error) {
-	var leftValue, rightValue any
-
-	if leftValue, rightValue, err = opTerm.evalInfix(ctx); err != nil {
-		return
-	}
-
-	v, err = bitwiseXor(opTerm, leftValue, rightValue)
-	return
-}
-
-// init
-func init() {
-	registerTermConstructor(SymTilde, newBitwiseNotTerm)
-	registerTermConstructor(SymAmpersand, newBitwiseAndTerm)
-	registerTermConstructor(SymVertBar, newBitwiseOrTerm)
-	registerTermConstructor(SymCaret, newBitwiseXorTerm)
-}

operator-bool.go

@@ -18,17 +18,17 @@ func newNotTerm(tk *Token) (inst *term) {
 	}
 }
 
-func evalNot(ctx ExprContext, opTerm *term) (v any, err error) {
+func evalNot(ctx ExprContext, self *term) (v any, err error) {
 	var rightValue any
 
-	if rightValue, err = opTerm.evalPrefix(ctx); err != nil {
+	if rightValue, err = self.evalPrefix(ctx); err != nil {
 		return
 	}
 
-	if b, ok := ToBool(rightValue); ok {
+	if b, ok := toBool(rightValue); ok {
 		v = !b
 	} else {
-		err = opTerm.errIncompatibleType(rightValue)
+		err = self.errIncompatibleType(rightValue)
 	}
 	return
 }
@@ -38,6 +38,8 @@ func evalNot(ctx ExprContext, opTerm *term) (v any, err error) {
 func newAndTerm(tk *Token) (inst *term) {
 	return &term{
 		tk: *tk,
+		// class:    classOperator,
+		// kind:     kindBool,
 		children: make([]*term, 0, 2),
 		position: posInfix,
 		priority: priAnd,
@@ -46,7 +48,7 @@ func newAndTerm(tk *Token) (inst *term) {
 }
 
 func evalAnd(ctx ExprContext, self *term) (v any, err error) {
-	if CtrlIsEnabled(ctx, ControlBoolShortcut) {
+	if isEnabled(ctx, ControlBoolShortcut) {
 		v, err = evalAndWithShortcut(ctx, self)
 	} else {
 		v, err = evalAndWithoutShortcut(ctx, self)
@@ -63,8 +65,8 @@ func evalAndWithoutShortcut(ctx ExprContext, self *term) (v any, err error) {
 		return
 	}
 
-	leftBool, lok = ToBool(leftValue)
+	leftBool, lok = toBool(leftValue)
-	rightBool, rok = ToBool(rightValue)
+	rightBool, rok = toBool(rightValue)
 
 	if lok && rok {
 		v = leftBool && rightBool
@@ -85,13 +87,13 @@ func evalAndWithShortcut(ctx ExprContext, self *term) (v any, err error) {
 		return
 	}
 
-	if leftBool, lok := ToBool(leftValue); !lok {
+	if leftBool, lok := toBool(leftValue); !lok {
-		err = fmt.Errorf("got %s as left operand type of 'AND' operator, it must be bool", TypeName(leftValue))
+		err = fmt.Errorf("got %T as left operand type of 'and' operator, it must be bool", leftBool)
 		return
 	} else if !leftBool {
 		v = false
 	} else if rightValue, err = self.children[1].compute(ctx); err == nil {
-		if rightBool, rok := ToBool(rightValue); rok {
+		if rightBool, rok := toBool(rightValue); rok {
 			v = rightBool
 		} else {
 			err = self.errIncompatibleTypes(leftValue, rightValue)
@@ -105,6 +107,8 @@ func evalAndWithShortcut(ctx ExprContext, self *term) (v any, err error) {
 func newOrTerm(tk *Token) (inst *term) {
 	return &term{
 		tk: *tk,
+		// class:    classOperator,
+		// kind:     kindBool,
 		children: make([]*term, 0, 2),
 		position: posInfix,
 		priority: priOr,
@@ -113,7 +117,7 @@ func newOrTerm(tk *Token) (inst *term) {
 }
 
 func evalOr(ctx ExprContext, self *term) (v any, err error) {
-	if CtrlIsEnabled(ctx, ControlBoolShortcut) {
+	if isEnabled(ctx, ControlBoolShortcut) {
 		v, err = evalOrWithShortcut(ctx, self)
 	} else {
 		v, err = evalOrWithoutShortcut(ctx, self)
@@ -130,8 +134,8 @@ func evalOrWithoutShortcut(ctx ExprContext, self *term) (v any, err error) {
 		return
 	}
 
-	leftBool, lok = ToBool(leftValue)
+	leftBool, lok = toBool(leftValue)
-	rightBool, rok = ToBool(rightValue)
+	rightBool, rok = toBool(rightValue)
 
 	if lok && rok {
 		v = leftBool || rightBool
@@ -152,13 +156,13 @@ func evalOrWithShortcut(ctx ExprContext, self *term) (v any, err error) {
 		return
 	}
 
-	if leftBool, lok := ToBool(leftValue); !lok {
+	if leftBool, lok := toBool(leftValue); !lok {
-		err = fmt.Errorf("got %s as left operand type of 'OR' operator, it must be bool", TypeName(leftValue))
+		err = fmt.Errorf("got %T as left operand type of 'or' operator, it must be bool", leftBool)
 		return
 	} else if leftBool {
 		v = true
 	} else if rightValue, err = self.children[1].compute(ctx); err == nil {
-		if rightBool, rok := ToBool(rightValue); rok {
+		if rightBool, rok := toBool(rightValue); rok {
 			v = rightBool
 		} else {
 			err = self.errIncompatibleTypes(leftValue, rightValue)

operator-builtin.go

@@ -1,11 +1,9 @@
 // Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
 // All rights reserved.
 
-// operator-builtin.go
+// operator-length.go
 package expr
 
-import "io"
-
 //-------- builtin term
 
 func newBuiltinTerm(tk *Token) (inst *term) {
@@ -18,39 +16,37 @@ func newBuiltinTerm(tk *Token) (inst *term) {
 	}
 }
 
-func evalBuiltin(ctx ExprContext, opTerm *term) (v any, err error) {
+func evalBuiltin(ctx ExprContext, self *term) (v any, err error) {
-	var childValue any
+	var rightValue any
 
-	if childValue, err = opTerm.evalPrefix(ctx); err != nil {
+	if rightValue, err = self.evalPrefix(ctx); err != nil {
 		return
 	}
 
 	count := 0
-	if IsString(childValue) {
+	if isList(rightValue) {
-		module, _ := childValue.(string)
+		list, _ := rightValue.([]any)
-		count, err = ImportInContextByGlobPattern(module)
+		for i, moduleSpec := range list {
-	} else {
-		var moduleSpec any
-		it := NewAnyIterator(childValue)
-		for moduleSpec, err = it.Next(); err == nil; moduleSpec, err = it.Next() {
 			if module, ok := moduleSpec.(string); ok {
-				if ImportInContext(module) {
+				if ImportInContext(ctx, module) {
 					count++
 				} else {
-					err = opTerm.Errorf("unknown builtin module %q", module)
+					err = self.Errorf("unknown module %q", module)
 					break
 				}
 			} else {
-				err = opTerm.Errorf("expected string at item nr %d, got %s", it.Index()+1, TypeName(moduleSpec))
+				err = self.Errorf("expected string at item nr %d, got %T", i+1, moduleSpec)
 				break
 			}
 		}
-		if err == io.EOF {
+	} else if isString(rightValue) {
-			err = nil
+		module, _ := rightValue.(string)
-		}
+		count, err = ImportInContextByGlobPattern(ctx, module)
+	} else {
+		err = self.errIncompatibleType(rightValue)
 	}
 	if err == nil {
-		v = int64(count)
+		v = count
 	}
 	return
 }

operator-but.go

@@ -16,8 +16,8 @@ func newButTerm(tk *Token) (inst *term) {
 	}
 }
 
-func evalBut(ctx ExprContext, opTerm *term) (v any, err error) {
+func evalBut(ctx ExprContext, self *term) (v any, err error) {
-	_, v, err = opTerm.evalInfix(ctx)
+	_, v, err = self.evalInfix(ctx)
 	return
 }
 

operator-coalesce.go

@@ -0,0 +1,93 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
+// operator-coalesce.go
+package expr
+
+//-------- null coalesce term
+
+func newNullCoalesceTerm(tk *Token) (inst *term) {
+	return &term{
+		tk: *tk,
+		// class:    classOperator,
+		// kind:     kindUnknown,
+		children: make([]*term, 0, 2),
+		position: posInfix,
+		priority: priCoalesce,
+		evalFunc: evalNullCoalesce,
+	}
+}
+
+func evalNullCoalesce(ctx ExprContext, self *term) (v any, err error) {
+	var rightValue any
+
+	if err = self.checkOperands(); err != nil {
+		return
+	}
+
+	leftTerm := self.children[0]
+	if leftTerm.tk.Sym != SymIdentifier {
+		err = leftTerm.Errorf("left operand of %q must be a variable", self.tk.source)
+		return
+	}
+
+	if leftValue, exists := ctx.GetVar(leftTerm.source()); exists {
+		v = leftValue
+	} else if rightValue, err = self.children[1].compute(ctx); err == nil {
+		if _, ok := rightValue.(Functor); ok {
+			err = errCoalesceNoFunc(self.children[1])
+		} else {
+			v = rightValue
+		}
+	}
+	return
+}
+
+//-------- coalesce assign term
+
+func newCoalesceAssignTerm(tk *Token) (inst *term) {
+	return &term{
+		tk:       *tk,
+		children: make([]*term, 0, 2),
+		position: posInfix,
+		priority: priCoalesce,
+		evalFunc: evalAssignCoalesce,
+	}
+}
+
+func evalAssignCoalesce(ctx ExprContext, self *term) (v any, err error) {
+	var rightValue any
+
+	if err = self.checkOperands(); err != nil {
+		return
+	}
+
+	leftTerm := self.children[0]
+	if leftTerm.tk.Sym != SymIdentifier {
+		err = leftTerm.Errorf("left operand of %q must be a variable", self.tk.source)
+		return
+	}
+
+	if leftValue, exists := ctx.GetVar(leftTerm.source()); exists {
+		v = leftValue
+	} else if rightValue, err = self.children[1].compute(ctx); err == nil {
+		if _, ok := rightValue.(Functor); ok {
+			err = errCoalesceNoFunc(self.children[1])
+		} else {
+			v = rightValue
+			ctx.setVar(leftTerm.source(), rightValue)
+		}
+	}
+	return
+}
+
+// utils
+func errCoalesceNoFunc(t *term) error {
+	return t.Errorf("the right operand of a coalescing operation cannot be a function definition")
+}
+
+// init
+func init() {
+	registerTermConstructor(SymDoubleQuestion, newNullCoalesceTerm)
+	registerTermConstructor(SymQuestionEqual, newCoalesceAssignTerm)
+}

operator-context.go

@@ -1,60 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// operator-context-value.go
-package expr
-
-//-------- context term
-
-func newContextTerm(tk *Token) (inst *term) {
-	return &term{
-		tk:       *tk,
-		children: make([]*term, 0, 1),
-		position: posPrefix,
-		priority: priIncDec,
-		evalFunc: evalContextValue,
-	}
-}
-
-func evalContextValue(ctx ExprContext, opTerm *term) (v any, err error) {
-	var childValue any
-
-	var sourceCtx ExprContext
-	if len(opTerm.children) == 0 {
-		sourceCtx = ctx
-	} else if opTerm.children[0].symbol() == SymVariable && opTerm.children[0].source() == "global" {
-		sourceCtx = globalCtx
-	} else if childValue, err = opTerm.evalPrefix(ctx); err == nil {
-		if dc, ok := childValue.(*dataCursor); ok {
-			sourceCtx = dc.ctx
-		}
-	}
-
-	if sourceCtx != nil {
-		if formatter, ok := sourceCtx.(DictFormat); ok {
-			v = formatter.ToDict()
-		} else if formatter, ok := sourceCtx.(Formatter); ok {
-			v = formatter.ToString(0)
-		} else {
-			// keys := sourceCtx.EnumVars(func(name string) bool { return name[0] != '_' })
-			keys := sourceCtx.EnumVars(nil)
-			d := make(map[string]any)
-			for _, key := range keys {
-				d[key], _ = sourceCtx.GetVar(key)
-			}
-			keys = sourceCtx.EnumFuncs(func(name string) bool { return true })
-			for _, key := range keys {
-				d[key], _ = sourceCtx.GetFuncInfo(key)
-			}
-			v = d
-		}
-	} else {
-		err = opTerm.errIncompatibleType(childValue)
-	}
-	return
-}
-
-// init
-func init() {
-	registerTermConstructor(SymDoubleDollar, newContextTerm)
-}

operator-ctrl.go

@@ -16,8 +16,8 @@ func newExportAllTerm(tk *Token) (inst *term) {
 	}
 }
 
-func evalExportAll(ctx ExprContext, opTerm *term) (v any, err error) {
+func evalExportAll(ctx ExprContext, self *term) (v any, err error) {
-	CtrlEnable(ctx, control_export_all)
+	enable(ctx, control_export_all)
 	return
 }
 

operator-default.go

@@ -1,124 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// operator-default.go
-package expr
-
-//-------- default term
-
-func newDefaultTerm(tk *Token) (inst *term) {
-	return &term{
-		tk:       *tk,
-		children: make([]*term, 0, 2),
-		position: posInfix,
-		priority: priDefault,
-		evalFunc: evalDefault,
-	}
-}
-
-func evalDefault(ctx ExprContext, opTerm *term) (v any, err error) {
-	var rightValue any
-
-	if err = opTerm.checkOperands(); err != nil {
-		return
-	}
-
-	leftTerm := opTerm.children[0]
-	if leftTerm.tk.Sym != SymVariable {
-		// err = leftTerm.Errorf("left operand of %q must be a variable", self.tk.source)
-		err = ErrLeftOperandMustBeVariable(leftTerm, opTerm)
-		return
-	}
-
-	if leftValue, exists := ctx.GetVar(leftTerm.source()); exists {
-		v = leftValue
-	} else if rightValue, err = opTerm.children[1].compute(ctx); err == nil {
-		v = rightValue
-	}
-	return
-}
-
-//-------- alternate term
-
-func newAlternateTerm(tk *Token) (inst *term) {
-	return &term{
-		tk:       *tk,
-		children: make([]*term, 0, 2),
-		position: posInfix,
-		priority: priDefault,
-		evalFunc: evalAlternate,
-	}
-}
-
-func evalAlternate(ctx ExprContext, opTerm *term) (v any, err error) {
-	var rightValue any
-
-	if err = opTerm.checkOperands(); err != nil {
-		return
-	}
-
-	leftTerm := opTerm.children[0]
-	if leftTerm.tk.Sym != SymVariable {
-		// err = leftTerm.Errorf("left operand of %q must be a variable", self.tk.source)
-		err = ErrLeftOperandMustBeVariable(leftTerm, opTerm)
-		return
-	}
-
-	if leftValue, exists := ctx.GetVar(leftTerm.source()); exists && leftValue != nil {
-		if rightValue, err = opTerm.children[1].compute(ctx); err == nil {
-			v = rightValue
-		}
-	} else {
-		v = leftValue
-	}
-	return
-}
-
-//-------- default assign term
-
-func newDefaultAssignTerm(tk *Token) (inst *term) {
-	return &term{
-		tk:       *tk,
-		children: make([]*term, 0, 2),
-		position: posInfix,
-		priority: priDefault,
-		evalFunc: evalAssignDefault,
-	}
-}
-
-func evalAssignDefault(ctx ExprContext, opTerm *term) (v any, err error) {
-	var rightValue any
-
-	if err = opTerm.checkOperands(); err != nil {
-		return
-	}
-
-	leftTerm := opTerm.children[0]
-	if leftTerm.tk.Sym != SymVariable {
-		// err = leftTerm.Errorf("left operand of %q must be a variable", self.tk.source)
-		err = ErrLeftOperandMustBeVariable(leftTerm, opTerm)
-		return
-	}
-
-	if leftValue, exists := ctx.GetVar(leftTerm.source()); exists {
-		v = leftValue
-	} else if rightValue, err = opTerm.children[1].compute(ctx); err == nil {
-		if functor, ok := rightValue.(Functor); ok {
-			//ctx.RegisterFunc(leftTerm.source(), functor, 0, -1)
-			ctx.RegisterFunc(leftTerm.source(), functor, TypeAny, []ExprFuncParam{
-				NewFuncParamFlag(ParamValue, PfDefault|PfRepeat),
-			})
-		} else {
-			v = rightValue
-			ctx.UnsafeSetVar(leftTerm.source(), rightValue)
-		}
-	}
-	return
-}
-
-// init
-func init() {
-	registerTermConstructor(SymDoubleQuestion, newDefaultTerm)
-	registerTermConstructor(SymQuestionEqual, newDefaultAssignTerm)
-	registerTermConstructor(SymQuestionExclam, newAlternateTerm)
-}

operator-dot.go

@@ -15,35 +15,42 @@ func newDotTerm(tk *Token) (inst *term) {
 	}
 }
 
-func evalDot(ctx ExprContext, opTerm *term) (v any, err error) {
+func evalDot(ctx ExprContext, self *term) (v any, err error) {
 	var leftValue, rightValue any
 
-	if err = opTerm.checkOperands(); err != nil {
+	if leftValue, rightValue, err = self.evalInfix(ctx); err != nil {
-		return
-	}
-	if leftValue, err = opTerm.children[0].compute(ctx); err != nil {
 		return
 	}
 
-	indexTerm := opTerm.children[1]
+	indexTerm := self.children[1]
+	if !isInteger(rightValue) {
+		err = indexTerm.Errorf("index expression must be integer, got %T", rightValue)
+		return
+	}
 
-	switch unboxedValue := leftValue.(type) {
+	index64, _ := rightValue.(int64)
-	case ExtIterator:
+	index := int(index64)
-		if indexTerm.symbol() == SymVariable /*|| indexTerm.symbol() == SymString */ {
+
-			opName := indexTerm.source()
+	if isList(leftValue) {
-			if unboxedValue.HasOperation(opName) {
+		list, _ := leftValue.([]any)
-				v, err = unboxedValue.CallOperation(opName, map[string]any{})
+		if index >= 0 && index < len(list) {
+			v = list[index]
+		} else if index >= -len(list) {
+			v = list[len(list)+index]
 		} else {
-				err = indexTerm.Errorf("this iterator do not support the %q command", opName)
+			err = indexTerm.Errorf("index %v out of bounds", index)
-				v = false
+		}
+	} else if isString(leftValue) {
+		s, _ := leftValue.(string)
+		if index >= 0 && index < len(s) {
+			v = string(s[index])
+		} else if index >= -len(s) {
+			v = string(s[len(s)+index])
+		} else {
+			err = indexTerm.Errorf("index %v out of bounds", index)
 		}
 	} else {
-			err = indexTerm.tk.ErrorExpectedGot("identifier")
+		err = self.errIncompatibleTypes(leftValue, rightValue)
-		}
-	default:
-		if rightValue, err = opTerm.children[1].compute(ctx); err == nil {
-			err = opTerm.errIncompatibleTypes(leftValue, rightValue)
-		}
 	}
 	return
 }

operator-fact.go

@@ -18,14 +18,14 @@ func newFactTerm(tk *Token) (inst *term) {
 	}
 }
 
-func evalFact(ctx ExprContext, opTerm *term) (v any, err error) {
+func evalFact(ctx ExprContext, self *term) (v any, err error) {
 	var leftValue any
 
-	if leftValue, err = opTerm.evalPrefix(ctx); err != nil {
+	if leftValue, err = self.evalPrefix(ctx); err != nil {
 		return
 	}
 
-	if IsInteger(leftValue) {
+	if isInteger(leftValue) {
 		if i, _ := leftValue.(int64); i >= 0 {
 			f := int64(1)
 			for k := int64(1); k <= i; k++ {
@@ -36,7 +36,7 @@ func evalFact(ctx ExprContext, opTerm *term) (v any, err error) {
 			err = fmt.Errorf("factorial of a negative integer (%d) is not allowed", i)
 		}
 	} else {
-		err = opTerm.errIncompatibleType(leftValue)
+		err = self.errIncompatibleType(leftValue)
 	}
 	return
 }

operator-fraction.go

@@ -1,70 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// operand-fraction.go
-package expr
-
-//https://www.youmath.it/lezioni/algebra-elementare/lezioni-di-algebra-e-aritmetica-per-scuole-medie/553-dalle-frazioni-a-numeri-decimali.html
-
-import (
-	"fmt"
-)
-
-// -------- fraction term
-func newFractionTerm(tk *Token) *term {
-	return &term{
-		tk:       *tk,
-		parent:   nil,
-		children: make([]*term, 0, 2),
-		position: posInfix,
-		priority: priFraction,
-		evalFunc: evalFraction,
-	}
-}
-
-// -------- eval func
-func evalFraction(ctx ExprContext, opTerm *term) (v any, err error) {
-	var numValue, denValue any
-	var num, den int64
-	var ok bool
-
-	if numValue, denValue, err = opTerm.evalInfix(ctx); err != nil {
-		return
-	}
-	if num, ok = numValue.(int64); !ok {
-		err = fmt.Errorf("numerator must be integer, got %T (%v)", numValue, numValue)
-		return
-	}
-	if den, ok = denValue.(int64); !ok {
-		err = fmt.Errorf("denominator must be integer, got %T (%v)", denValue, denValue)
-		return
-	}
-	if den == 0 {
-		err = opTerm.errDivisionByZero()
-		return
-	}
-
-	if den < 0 {
-		den = -den
-		num = -num
-	}
-	if num != 0 {
-		g := gcd(num, den)
-		num = num / g
-		den = den / g
-		if den == 1 {
-			v = num
-		} else {
-			v = &FractionType{num, den}
-		}
-	} else {
-		v = &FractionType{0, den}
-	}
-	return
-}
-
-// init
-func init() {
-	// registerTermConstructor(SymVertBar, newFractionTerm)
-	registerTermConstructor(SymColon, newFractionTerm)
-}

operator-in.go

@@ -1,46 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// operator-in.go
-package expr
-
-//-------- in term
-
-func newInTerm(tk *Token) (inst *term) {
-	return &term{
-		tk:       *tk,
-		children: make([]*term, 0, 2),
-		position: posInfix,
-		priority: priRelational,
-		evalFunc: evalIn,
-	}
-}
-
-// func hasKey(d map[any]any, target any) (ok bool) {
-// 	_, ok = d[target]
-// 	return
-// }
-
-func evalIn(ctx ExprContext, opTerm *term) (v any, err error) {
-	var leftValue, rightValue any
-
-	if leftValue, rightValue, err = opTerm.evalInfix(ctx); err != nil {
-		return
-	}
-
-	if IsList(rightValue) {
-		list, _ := rightValue.(*ListType)
-		v = list.indexDeepSameCmp(leftValue) >= 0
-	} else if IsDict(rightValue) {
-		dict, _ := rightValue.(*DictType)
-		v = dict.hasKey(leftValue)
-	} else {
-		err = opTerm.errIncompatibleTypes(leftValue, rightValue)
-	}
-	return
-}
-
-// init
-func init() {
-	registerTermConstructor(SymKwIn, newInTerm)
-}

operator-include.go

@@ -1,60 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// operator-include.go
-package expr
-
-//-------- include term
-
-func newIncludeTerm(tk *Token) (inst *term) {
-	return &term{
-		tk:       *tk,
-		children: make([]*term, 0, 1),
-		position: posPrefix,
-		priority: priSign,
-		evalFunc: evalInclude,
-	}
-}
-
-func evalInclude(ctx ExprContext, opTerm *term) (v any, err error) {
-	var childValue any
-
-	if childValue, err = opTerm.evalPrefix(ctx); err != nil {
-		return
-	}
-
-	count := 0
-	if IsList(childValue) {
-		list, _ := childValue.(*ListType)
-		for i, filePathSpec := range *list {
-			if filePath, ok := filePathSpec.(string); ok {
-				if v, err = EvalFile(ctx, filePath); err == nil {
-					count++
-				} else {
-					err = opTerm.Errorf("can't load file %q", filePath)
-					break
-				}
-			} else {
-				err = opTerm.Errorf("expected string at item nr %d, got %T", i+1, filePathSpec)
-				break
-			}
-		}
-	} else if IsString(childValue) {
-		filePath, _ := childValue.(string)
-		if v, err = EvalFile(ctx, filePath); err == nil {
-			count++
-		}
-	} else {
-		err = opTerm.errIncompatibleType(childValue)
-	}
-	if err != nil {
-		//v = count
-		v = nil
-	}
-	return
-}
-
-// init
-func init() {
-	registerTermConstructor(SymKwInclude, newIncludeTerm)
-}

operator-index.go

@@ -1,138 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// operator-index.go
-package expr
-
-// -------- index term
-func newIndexTerm(tk *Token) (inst *term) {
-	return &term{
-		tk:       *tk,
-		children: make([]*term, 0, 2),
-		position: posInfix,
-		priority: priDot,
-		evalFunc: evalIndex,
-	}
-}
-
-func verifyKey(indexList *ListType) (index any, err error) {
-	index = (*indexList)[0]
-	return
-}
-
-func verifyIndex(indexTerm *term, indexList *ListType, maxValue int) (index int, err error) {
-	var v int
-
-	if v, err = ToGoInt((*indexList)[0], "index expression"); err == nil {
-		if v < 0 && v >= -maxValue {
-			v = maxValue + v
-		}
-		if v >= 0 && v < maxValue {
-			index = v
-		} else {
-			err = indexTerm.Errorf("index %d out of bounds", v)
-		}
-	}
-	return
-}
-
-func verifyRange(indexTerm *term, indexList *ListType, maxValue int) (startIndex, endIndex int, err error) {
-	v, _ := ((*indexList)[0]).(*intPair)
-	startIndex = v.a
-	endIndex = v.b
-	if endIndex == ConstLastIndex {
-		endIndex = maxValue
-	}
-	if startIndex < 0 && startIndex >= -maxValue {
-		startIndex = maxValue + startIndex
-	}
-	if endIndex < 0 && endIndex >= -maxValue {
-		endIndex = maxValue + endIndex
-	}
-	if startIndex < 0 || startIndex > maxValue {
-		err = indexTerm.Errorf("range start-index %d is out of bounds", startIndex)
-	} else if endIndex < 0 || endIndex > maxValue {
-		err = indexTerm.Errorf("range end-index %d is out of bounds", endIndex)
-	} else if startIndex > endIndex {
-		err = indexTerm.Errorf("range start-index %d must not be greater than end-index %d", startIndex, endIndex)
-	}
-	return
-}
-
-func evalIndex(ctx ExprContext, opTerm *term) (v any, err error) {
-	var leftValue, rightValue any
-	var indexList *ListType
-	var ok bool
-
-	if leftValue, rightValue, err = opTerm.evalInfix(ctx); err != nil {
-		return
-	}
-
-	indexTerm := opTerm.children[1]
-	if indexList, ok = rightValue.(*ListType); !ok {
-		err = opTerm.Errorf("invalid index expression")
-		return
-	} else if len(*indexList) != 1 {
-		err = indexTerm.Errorf("one index only is allowed")
-		return
-	}
-
-	if IsInteger((*indexList)[0]) {
-		switch unboxedValue := leftValue.(type) {
-		case *ListType:
-			var index int
-			if index, err = verifyIndex(indexTerm, indexList, len(*unboxedValue)); err == nil {
-				v = (*unboxedValue)[index]
-			}
-		case string:
-			var index int
-			if index, err = verifyIndex(indexTerm, indexList, len(unboxedValue)); err == nil {
-				v = string(unboxedValue[index])
-			}
-		case *DictType:
-			v, err = getDictItem(unboxedValue, indexTerm, indexList, rightValue)
-		default:
-			err = opTerm.errIncompatibleTypes(leftValue, rightValue)
-		}
-	} else if isIntPair((*indexList)[0]) {
-		switch unboxedValue := leftValue.(type) {
-		case *ListType:
-			var start, end int
-			if start, end, err = verifyRange(indexTerm, indexList, len(*unboxedValue)); err == nil {
-				sublist := ListType((*unboxedValue)[start:end])
-				v = &sublist
-			}
-		case string:
-			var start, end int
-			if start, end, err = verifyRange(indexTerm, indexList, len(unboxedValue)); err == nil {
-				v = unboxedValue[start:end]
-			}
-		default:
-			err = opTerm.errIncompatibleTypes(leftValue, rightValue)
-		}
-	} else if IsDict(leftValue) {
-		d := leftValue.(*DictType)
-		v, err = getDictItem(d, indexTerm, indexList, rightValue)
-	} else {
-		rightChild := opTerm.children[1]
-		err = rightChild.Errorf("invalid index type: %v", (*indexList)[0])
-	}
-	return
-}
-
-func getDictItem(d *DictType, indexTerm *term, indexList *ListType, rightValue any) (v any, err error) {
-	var ok bool
-	var indexValue any
-
-	if indexValue, err = verifyKey(indexList); err == nil {
-		if v, ok = (*d)[indexValue]; !ok {
-			err = indexTerm.Errorf("key %v does not belong to the dictionary", rightValue)
-		}
-	}
-	return
-}
-
-// init
-func init() {
-	registerTermConstructor(SymIndex, newIndexTerm)
-}

operator-insert.go

@@ -4,15 +4,15 @@
 // operator-insert.go
 package expr
 
-//-------- prepend term
+//-------- insert term
 
-func newPrependTerm(tk *Token) (inst *term) {
+func newInsertTerm(tk *Token) (inst *term) {
 	return &term{
 		tk:       *tk,
 		children: make([]*term, 0, 2),
 		position: posInfix,
-		priority: priInsert,
+		priority: priAssign,
-		evalFunc: evalPrepend,
+		evalFunc: evalInsert,
 	}
 }
 
@@ -21,71 +21,45 @@ func newAppendTerm(tk *Token) (inst *term) {
 		tk:       *tk,
 		children: make([]*term, 0, 2),
 		position: posInfix,
-		priority: priInsert,
+		priority: priAssign,
 		evalFunc: evalAppend,
 	}
 }
 
-func evalPrepend(ctx ExprContext, opTerm *term) (v any, err error) {
+func evalInsert(ctx ExprContext, self *term) (v any, err error) {
 	var leftValue, rightValue any
 
-	if leftValue, rightValue, err = opTerm.evalInfix(ctx); err != nil {
+	if leftValue, rightValue, err = self.evalInfix(ctx); err != nil {
 		return
 	}
 
-	if IsList(rightValue) {
+	if isList(rightValue) {
-		list, _ := rightValue.(*ListType)
+		list, _ := rightValue.([]any)
-		newList := append(ListType{leftValue}, *list...)
+		v = append([]any{leftValue}, list...)
-		v = &newList
-		if opTerm.children[1].symbol() == SymVariable {
-			ctx.UnsafeSetVar(opTerm.children[1].source(), v)
-		}
 	} else {
-		err = opTerm.errIncompatibleTypes(leftValue, rightValue)
+		err = self.errIncompatibleTypes(leftValue, rightValue)
 	}
 	return
 }
 
-func evalAppend(ctx ExprContext, opTerm *term) (v any, err error) {
+func evalAppend(ctx ExprContext, self *term) (v any, err error) {
 	var leftValue, rightValue any
 
-	if leftValue, rightValue, err = opTerm.evalInfix(ctx); err != nil {
+	if leftValue, rightValue, err = self.evalInfix(ctx); err != nil {
 		return
 	}
 
-	if IsList(leftValue) {
+	if isList(leftValue) {
-		list, _ := leftValue.(*ListType)
+		list, _ := leftValue.([]any)
-		newList := append(*list, rightValue)
+		v = append(list, rightValue)
-		v = &newList
-		if opTerm.children[0].symbol() == SymVariable {
-			ctx.UnsafeSetVar(opTerm.children[0].source(), v)
-		}
 	} else {
-		err = opTerm.errIncompatibleTypes(leftValue, rightValue)
+		err = self.errIncompatibleTypes(leftValue, rightValue)
 	}
 	return
 }
 
-// func evalAssignAppend(ctx ExprContext, self *term) (v any, err error) {
-// 	var leftValue, rightValue any
-
-// 	if leftValue, rightValue, err = self.evalInfix(ctx); err != nil {
-// 		return
-// 	}
-
-// 	if IsList(leftValue) {
-// 		list, _ := leftValue.(*ListType)
-// 		newList := append(*list, rightValue)
-// 		v = &newList
-// 		if
-// 	} else {
-// 		err = self.errIncompatibleTypes(leftValue, rightValue)
-// 	}
-// 	return
-// }
-
 // init
 func init() {
-	registerTermConstructor(SymPlusGreater, newPrependTerm)
+	registerTermConstructor(SymInsert, newInsertTerm)
-	registerTermConstructor(SymLessPlus, newAppendTerm)
+	registerTermConstructor(SymAppend, newAppendTerm)
 }

operator-iter-value.go

@@ -1,38 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// operator-iter-value.go
-package expr
-
-//-------- iter value term
-
-func newIterValueTerm(tk *Token) (inst *term) {
-	return &term{
-		tk:       *tk,
-		children: make([]*term, 0, 1),
-		position: posPrefix,
-		priority: priDereference,
-		evalFunc: evalIterValue,
-	}
-}
-
-func evalIterValue(ctx ExprContext, opTerm *term) (v any, err error) {
-	var childValue any
-
-	if childValue, err = opTerm.evalPrefix(ctx); err != nil {
-		return
-	}
-
-	if it, ok := childValue.(Iterator); ok {
-		v, err = it.Current()
-	} else {
-		err = opTerm.errIncompatibleType(childValue)
-	}
-	return
-}
-
-// init
-func init() {
-	//	registerTermConstructor(SymOpenClosedRound, newIterValueTerm)
-	registerTermConstructor(SymDereference, newIterValueTerm)
-}

operator-length.go

@@ -16,32 +16,24 @@ func newLengthTerm(tk *Token) (inst *term) {
 	}
 }
 
-func evalLength(ctx ExprContext, opTerm *term) (v any, err error) {
+func evalLength(ctx ExprContext, self *term) (v any, err error) {
-	var childValue any
+	var rightValue any
 
-	if childValue, err = opTerm.evalPrefix(ctx); err != nil {
+	if rightValue, err = self.evalPrefix(ctx); err != nil {
 		return
 	}
 
-	if IsList(childValue) {
+	if isList(rightValue) {
-		ls, _ := childValue.(*ListType)
+		list, _ := rightValue.([]any)
-		v = int64(len(*ls))
+		v = len(list)
-	} else if IsString(childValue) {
+	} else if isString(rightValue) {
-		s, _ := childValue.(string)
+		s, _ := rightValue.(string)
-		v = int64(len(s))
+		v = len(s)
-	} else if IsDict(childValue) {
-		m, _ := childValue.(*DictType)
-		v = int64(len(*m))
-	} else if it, ok := childValue.(Iterator); ok {
-		v = int64(it.Count())
-		// if extIt, ok := childValue.(ExtIterator); ok && extIt.HasOperation(CountName) {
-		// 	count, _ := extIt.CallOperation(CountName, nil)
-		// 	v, _ = ToGoInt(count, "")
 		// } else {
-		// 	v = int64(it.Index() + 1)
+		// 	v = 1
 		// }
 	} else {
-		err = opTerm.errIncompatibleType(childValue)
+		err = self.errIncompatibleType(rightValue)
 	}
 	return
 }

operator-plugin.go

@@ -1,36 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// operator-plugin.go
-package expr
-
-//-------- plugin term
-
-func newPluginTerm(tk *Token) (inst *term) {
-	return &term{
-		tk:       *tk,
-		children: make([]*term, 0, 1),
-		position: posPrefix,
-		priority: priSign,
-		evalFunc: evalPlugin,
-	}
-}
-
-func evalPlugin(ctx ExprContext, opTerm *term) (v any, err error) {
-	var childValue any
-	var count int
-
-	if childValue, err = opTerm.evalPrefix(ctx); err != nil {
-		return
-	}
-
-	if count, err = importPluginFromSearchPath(childValue); err == nil {
-		v = int64(count)
-	}
-	return
-}
-
-// init
-func init() {
-	registerTermConstructor(SymKwPlugin, newPluginTerm)
-}

operator-post-inc-dec.go

@@ -1,73 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// operator-post-inc-dec.go
-package expr
-
-// -------- post increment term
-
-func newPostIncTerm(tk *Token) *term {
-	return &term{
-		tk:       *tk,
-		parent:   nil,
-		children: make([]*term, 0, 1),
-		position: posPostfix,
-		priority: priIncDec,
-		evalFunc: evalPostInc,
-	}
-}
-
-func evalPostInc(ctx ExprContext, opTerm *term) (v any, err error) {
-	var childValue any
-	if childValue, err = opTerm.evalPrefix(ctx); err != nil {
-		return
-	}
-
-	if it, ok := childValue.(Iterator); ok {
-		v, err = it.Next()
-	} else if IsInteger(childValue) && opTerm.children[0].symbol() == SymVariable {
-		v = childValue
-		i, _ := childValue.(int64)
-		ctx.SetVar(opTerm.children[0].source(), i+1)
-	} else {
-		err = opTerm.errIncompatibleType(childValue)
-	}
-	return
-}
-
-// -------- post decrement term
-
-func newPostDecTerm(tk *Token) *term {
-	return &term{
-		tk:       *tk,
-		parent:   nil,
-		children: make([]*term, 0, 1),
-		position: posPostfix,
-		priority: priIncDec,
-		evalFunc: evalPostDec,
-	}
-}
-
-func evalPostDec(ctx ExprContext, opTerm *term) (v any, err error) {
-	var childValue any
-	if childValue, err = opTerm.evalPrefix(ctx); err != nil {
-		return
-	}
-
-	/* if it, ok := childValue.(Iterator); ok {
-		v, err = it.Next()
-	} else  */if IsInteger(childValue) && opTerm.children[0].symbol() == SymVariable {
-		v = childValue
-		i, _ := childValue.(int64)
-		ctx.SetVar(opTerm.children[0].source(), i-1)
-	} else {
-		err = opTerm.errIncompatibleType(childValue)
-	}
-	return
-}
-
-// init
-func init() {
-	registerTermConstructor(SymDoublePlus, newPostIncTerm)
-	registerTermConstructor(SymDoubleMinus, newPostDecTerm)
-}

operator-pre-inc-dec.go

@@ -1,69 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// operator-pre-inc-dec.go
-package expr
-
-// -------- pre increment term
-
-func newPreIncTerm(tk *Token) *term {
-	return &term{
-		tk:       *tk,
-		parent:   nil,
-		children: make([]*term, 0, 1),
-		position: posPrefix,
-		priority: priIncDec,
-		evalFunc: evalPreInc,
-	}
-}
-
-func evalPreInc(ctx ExprContext, opTerm *term) (v any, err error) {
-	var childValue any
-	if childValue, err = opTerm.evalPrefix(ctx); err != nil {
-		return
-	}
-
-	if IsInteger(childValue) && opTerm.children[0].symbol() == SymVariable {
-		i := childValue.(int64) + 1
-		ctx.SetVar(opTerm.children[0].source(), i)
-		v = i
-	} else {
-		err = opTerm.errIncompatibleType(childValue)
-	}
-	return
-}
-
-// -------- pre decrement term
-
-func newPreDecTerm(tk *Token) *term {
-	return &term{
-		tk:       *tk,
-		parent:   nil,
-		children: make([]*term, 0, 1),
-		position: posPrefix,
-		priority: priIncDec,
-		evalFunc: evalPreDec,
-	}
-}
-
-func evalPreDec(ctx ExprContext, opTerm *term) (v any, err error) {
-	var childValue any
-	if childValue, err = opTerm.evalPrefix(ctx); err != nil {
-		return
-	}
-
-	if IsInteger(childValue) && opTerm.children[0].symbol() == SymVariable {
-		i := childValue.(int64) - 1
-		ctx.SetVar(opTerm.children[0].source(), i)
-		v = i
-	} else {
-		err = opTerm.errIncompatibleType(childValue)
-	}
-	return
-}
-
-// init
-func init() {
-	registerTermConstructor(SymPreInc, newPreIncTerm)
-	registerTermConstructor(SymPreDec, newPreDecTerm)
-}

operator-prod.go

@@ -5,6 +5,7 @@
 package expr
 
 import (
+	"errors"
 	"strings"
 )
 
@@ -13,6 +14,8 @@ import (
 func newMultiplyTerm(tk *Token) (inst *term) {
 	return &term{
 		tk: *tk,
+		// class:    classOperator,
+		// kind:     kindUnknown,
 		children: make([]*term, 0, 2),
 		position: posInfix,
 		priority: priProduct,
@@ -20,42 +23,38 @@ func newMultiplyTerm(tk *Token) (inst *term) {
 	}
 }
 
-func mulValues(opTerm *term, leftValue, rightValue any) (v any, err error) {
+func evalMultiply(ctx ExprContext, self *term) (v any, err error) {
-	if IsString(leftValue) && IsInteger(rightValue) {
+	var leftValue, rightValue any
+
+	if leftValue, rightValue, err = self.evalInfix(ctx); err != nil {
+		return
+	}
+
+	if isString(leftValue) && isInteger(rightValue) {
 		s, _ := leftValue.(string)
 		n, _ := rightValue.(int64)
 		v = strings.Repeat(s, int(n))
-	} else if isNumOrFract(leftValue) && isNumOrFract(rightValue) {
+	} else if isNumber(leftValue) && isNumber(rightValue) {
-		if IsFloat(leftValue) || IsFloat(rightValue) {
+		if isFloat(leftValue) || isFloat(rightValue) {
 			v = numAsFloat(leftValue) * numAsFloat(rightValue)
-		} else if isFraction(leftValue) || isFraction(rightValue) {
-			v, err = mulAnyFract(leftValue, rightValue)
 		} else {
 			leftInt, _ := leftValue.(int64)
 			rightInt, _ := rightValue.(int64)
 			v = leftInt * rightInt
 		}
 	} else {
-		err = opTerm.errIncompatibleTypes(leftValue, rightValue)
+		err = self.errIncompatibleTypes(leftValue, rightValue)
 	}
 	return
 }
 
-func evalMultiply(ctx ExprContext, prodTerm *term) (v any, err error) {
-	var leftValue, rightValue any
-
-	if leftValue, rightValue, err = prodTerm.evalInfix(ctx); err != nil {
-		return
-	}
-
-	return mulValues(prodTerm, leftValue, rightValue)
-}
-
 //-------- divide term
 
 func newDivideTerm(tk *Token) (inst *term) {
 	return &term{
 		tk: *tk,
+		// class:    classOperator,
+		// kind:     kindUnknown,
 		children: make([]*term, 0, 2),
 		position: posInfix,
 		priority: priProduct,
@@ -63,66 +62,35 @@ func newDivideTerm(tk *Token) (inst *term) {
 	}
 }
 
-func divValues(opTerm *term, leftValue, rightValue any) (v any, err error) {
+func evalDivide(ctx ExprContext, self *term) (v any, err error) {
-	if isNumOrFract(leftValue) && isNumOrFract(rightValue) {
+	var leftValue, rightValue any
-		if IsFloat(leftValue) || IsFloat(rightValue) {
+
+	if leftValue, rightValue, err = self.evalInfix(ctx); err != nil {
+		return
+	}
+
+	if isNumber(leftValue) && isNumber(rightValue) {
+		if isFloat(leftValue) || isFloat(rightValue) {
 			d := numAsFloat(rightValue)
 			if d == 0.0 {
-				err = opTerm.errDivisionByZero()
+				err = errors.New("division by zero")
 			} else {
 				v = numAsFloat(leftValue) / d
 			}
-		} else if isFraction(leftValue) || isFraction(rightValue) {
-			v, err = divAnyFract(leftValue, rightValue)
 		} else {
 			leftInt, _ := leftValue.(int64)
 			if rightInt, _ := rightValue.(int64); rightInt == 0 {
-				err = opTerm.errDivisionByZero()
+				err = errors.New("division by zero")
 			} else {
 				v = leftInt / rightInt
 			}
 		}
-	} else if IsString(leftValue) && IsString(rightValue) {
-		source := leftValue.(string)
-		sep := rightValue.(string)
-		v = ListFromStrings(strings.Split(source, sep))
-	} else if IsString(leftValue) && IsInteger(rightValue) {
-		source := leftValue.(string)
-		partSize := int(rightValue.(int64))
-		if partSize == 0 {
-			err = opTerm.errDivisionByZero()
 	} else {
-			partCount := len(source) / partSize
+		err = self.errIncompatibleTypes(leftValue, rightValue)
-			remainder := len(source) % partSize
-			listSize := partCount
-			if remainder > 0 {
-				listSize++
-			}
-			parts := make([]any, 0, listSize)
-			for i := 0; i < partCount; i++ {
-				parts = append(parts, source[i*partSize:(i+1)*partSize])
-			}
-			if remainder > 0 {
-				parts = append(parts, source[len(source)-remainder:])
-			}
-			v = newList(parts)
-		}
-	} else {
-		err = opTerm.errIncompatibleTypes(leftValue, rightValue)
 	}
 	return
 }
 
-func evalDivide(ctx ExprContext, opTerm *term) (v any, err error) {
-	var leftValue, rightValue any
-
-	if leftValue, rightValue, err = opTerm.evalInfix(ctx); err != nil {
-		return
-	}
-
-	return divValues(opTerm, leftValue, rightValue)
-}
-
 //-------- divide as float term
 
 func newDivideAsFloatTerm(tk *Token) (inst *term) {
@@ -135,66 +103,65 @@ func newDivideAsFloatTerm(tk *Token) (inst *term) {
 	}
 }
 
-func evalDivideAsFloat(ctx ExprContext, floatDivTerm *term) (v any, err error) {
+func evalDivideAsFloat(ctx ExprContext, self *term) (v any, err error) {
 	var leftValue, rightValue any
 
-	if leftValue, rightValue, err = floatDivTerm.evalInfix(ctx); err != nil {
+	if leftValue, rightValue, err = self.evalInfix(ctx); err != nil {
 		return
 	}
 
-	if isNumOrFract(leftValue) && isNumOrFract(rightValue) {
+	if isNumber(leftValue) && isNumber(rightValue) {
 		d := numAsFloat(rightValue)
 		if d == 0.0 {
-			err = floatDivTerm.errDivisionByZero()
+			err = errors.New("division by zero")
 		} else {
 			v = numAsFloat(leftValue) / d
 		}
 	} else {
-		err = floatDivTerm.errIncompatibleTypes(leftValue, rightValue)
+		err = self.errIncompatibleTypes(leftValue, rightValue)
 	}
 	return
 }
 
 //-------- reminder term
 
-func newRemainderTerm(tk *Token) (inst *term) {
+func newReminderTerm(tk *Token) (inst *term) {
 	return &term{
 		tk: *tk,
+		// class:    classOperator,
+		// kind:     kindUnknown,
 		children: make([]*term, 0, 2),
 		position: posInfix,
 		priority: priProduct,
-		evalFunc: evalRemainder,
+		evalFunc: evalReminder,
 	}
 }
-func remainderValues(opTerm *term, leftValue, rightValue any) (v any, err error) {
+
-	if IsInteger(leftValue) && IsInteger(rightValue) {
+func evalReminder(ctx ExprContext, self *term) (v any, err error) {
+	var leftValue, rightValue any
+
+	if leftValue, rightValue, err = self.evalInfix(ctx); err != nil {
+		return
+	}
+
+	if isInteger(leftValue) && isInteger(rightValue) {
 		rightInt, _ := rightValue.(int64)
 		if rightInt == 0 {
-			err = opTerm.errDivisionByZero()
+			err = errors.New("division by zero")
 		} else {
 			leftInt, _ := leftValue.(int64)
 			v = leftInt % rightInt
 		}
 	} else {
-		err = opTerm.errIncompatibleTypes(leftValue, rightValue)
+		err = self.errIncompatibleTypes(leftValue, rightValue)
 	}
 	return
 }
 
-func evalRemainder(ctx ExprContext, remainderTerm *term) (v any, err error) {
-	var leftValue, rightValue any
-
-	if leftValue, rightValue, err = remainderTerm.evalInfix(ctx); err != nil {
-		return
-	}
-
-	return remainderValues(remainderTerm, leftValue, rightValue)
-}
-
 // init
 func init() {
 	registerTermConstructor(SymStar, newMultiplyTerm)
 	registerTermConstructor(SymSlash, newDivideTerm)
 	registerTermConstructor(SymDotSlash, newDivideAsFloatTerm)
-	registerTermConstructor(SymPercent, newRemainderTerm)
+	registerTermConstructor(SymPercent, newReminderTerm)
 }

operator-range.go

@@ -1,82 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// operator-range.go
-package expr
-
-import "fmt"
-
-// -------- range term
-type intPair struct {
-	a, b int
-}
-
-func (p *intPair) TypeName() string {
-	return TypePair
-}
-
-func (p *intPair) ToString(opt FmtOpt) string {
-	return fmt.Sprintf("(%d, %d)", p.a, p.b)
-}
-
-func isIntPair(v any) bool {
-	_, ok := v.(*intPair)
-	return ok
-}
-
-func newRangeTerm(tk *Token) (inst *term) {
-	return &term{
-		tk:       *tk,
-		children: make([]*term, 0, 2),
-		position: posInfix,
-		priority: priRange,
-		evalFunc: evalRange,
-	}
-}
-
-func changeColonToRange(t *term) {
-	if t.tk.IsSymbol(SymColon) {
-		t.tk.Sym = SymRange
-		t.evalFunc = evalRange
-	}
-}
-
-func evalRange(ctx ExprContext, opTerm *term) (v any, err error) {
-	var leftValue, rightValue any
-
-	if len(opTerm.children) == 0 {
-		leftValue = int64(0)
-		rightValue = int64(-1)
-	} else if len(opTerm.children) == 1 {
-		if leftValue, err = opTerm.children[0].compute(ctx); err != nil {
-			return
-		}
-		rightValue = int64(ConstLastIndex)
-	} else if leftValue, rightValue, err = opTerm.evalInfix(ctx); err != nil {
-		return
-	}
-	if !(IsInteger(leftValue) && IsInteger(rightValue)) {
-		// err = opTerm.errIncompatibleTypes(leftValue, rightValue)
-		err = errRangeInvalidSpecification(opTerm)
-		return
-	}
-
-	startIndex, _ := leftValue.(int64)
-	endIndex, _ := rightValue.(int64)
-
-	v = &intPair{int(startIndex), int(endIndex)}
-	return
-}
-
-func errRangeInvalidSpecification(t *term) error {
-	return t.Errorf("invalid range specification")
-}
-
-func errRangeUnexpectedExpression(t *term) error {
-	return t.Errorf("unexpected range expression")
-}
-
-// init
-func init() {
-	registerTermConstructor(SymRange, newRangeTerm)
-}

operator-rel.go

@@ -4,13 +4,13 @@
 // operator-rel.go
 package expr
 
-import "reflect"
-
 //-------- equal term
 
 func newEqualTerm(tk *Token) (inst *term) {
 	return &term{
 		tk: *tk,
+		// class:    classOperator,
+		// kind:     kindBool,
 		children: make([]*term, 0, 2),
 		position: posInfix,
 		priority: priRelational,
@@ -18,41 +18,28 @@ func newEqualTerm(tk *Token) (inst *term) {
 	}
 }
 
-type deepFuncTemplate func(a, b any) (eq bool, err error)
+func evalEqual(ctx ExprContext, self *term) (v any, err error) {
-
-func equals(a, b any, deepCmp deepFuncTemplate) (eq bool, err error) {
-	if isNumOrFract(a) && isNumOrFract(b) {
-		if IsNumber(a) && IsNumber(b) {
-			if IsInteger(a) && IsInteger(b) {
-				li, _ := a.(int64)
-				ri, _ := b.(int64)
-				eq = li == ri
-			} else {
-				eq = numAsFloat(a) == numAsFloat(b)
-			}
-		} else {
-			var cmp int
-			if cmp, err = cmpAnyFract(a, b); err == nil {
-				eq = cmp == 0
-			}
-		}
-	} else if deepCmp != nil && IsList(a) && IsList(b) {
-		eq, err = deepCmp(a, b)
-	} else {
-		eq = reflect.DeepEqual(a, b)
-	}
-
-	return
-}
-
-func evalEqual(ctx ExprContext, opTerm *term) (v any, err error) {
 	var leftValue, rightValue any
 
-	if leftValue, rightValue, err = opTerm.evalInfix(ctx); err != nil {
+	if leftValue, rightValue, err = self.evalInfix(ctx); err != nil {
 		return
 	}
 
-	v, err = equals(leftValue, rightValue, nil)
+	if isNumber(leftValue) && isNumber(rightValue) {
+		if isInteger(leftValue) && isInteger(rightValue) {
+			li, _ := leftValue.(int64)
+			ri, _ := rightValue.(int64)
+			v = li == ri
+		} else {
+			v = numAsFloat(leftValue) == numAsFloat(rightValue)
+		}
+	} else if isString(leftValue) && isString(rightValue) {
+		ls, _ := leftValue.(string)
+		rs, _ := rightValue.(string)
+		v = ls == rs
+	} else {
+		err = self.errIncompatibleTypes(leftValue, rightValue)
+	}
 	return
 }
 
@@ -61,6 +48,8 @@ func evalEqual(ctx ExprContext, opTerm *term) (v any, err error) {
 func newNotEqualTerm(tk *Token) (inst *term) {
 	return &term{
 		tk: *tk,
+		// class:    classOperator,
+		// kind:     kindBool,
 		children: make([]*term, 0, 2),
 		position: posInfix,
 		priority: priRelational,
@@ -68,19 +57,46 @@ func newNotEqualTerm(tk *Token) (inst *term) {
 	}
 }
 
-func evalNotEqual(ctx ExprContext, opTerm *term) (v any, err error) {
+func evalNotEqual(ctx ExprContext, self *term) (v any, err error) {
-	if v, err = evalEqual(ctx, opTerm); err == nil {
+	if v, err = evalEqual(ctx, self); err == nil {
-		b, _ := ToBool(v)
+		b, _ := toBool(v)
 		v = !b
 	}
 	return
 }
 
+// func evalNotEqual(ctx exprContext, self *term) (v any, err error) {
+// 	var leftValue, rightValue any
+
+// 	if leftValue, rightValue, err = self.evalInfix(ctx); err != nil {
+// 		return
+// 	}
+
+// 	if isNumber(leftValue) && isNumber(rightValue) {
+// 		if isInteger(leftValue) && isInteger(rightValue) {
+// 			li, _ := leftValue.(int64)
+// 			ri, _ := rightValue.(int64)
+// 			v = li != ri
+// 		} else {
+// 			v = numAsFloat(leftValue) != numAsFloat(rightValue)
+// 		}
+// 	} else if isString(leftValue) && isString(rightValue) {
+// 		ls, _ := leftValue.(string)
+// 		rs, _ := rightValue.(string)
+// 		v = ls != rs
+// 	} else {
+// 		err = self.errIncompatibleTypes(leftValue, rightValue)
+// 	}
+// 	return
+// }
+
 //-------- less term
 
 func newLessTerm(tk *Token) (inst *term) {
 	return &term{
 		tk: *tk,
+		// class:    classOperator,
+		// kind:     kindBool,
 		children: make([]*term, 0, 2),
 		position: posInfix,
 		priority: priRelational,
@@ -88,44 +104,28 @@ func newLessTerm(tk *Token) (inst *term) {
 	}
 }
 
-func lessThan(self *term, a, b any) (isLess bool, err error) {
+func evalLess(ctx ExprContext, self *term) (v any, err error) {
-	if isNumOrFract(a) && isNumOrFract(b) {
-		if IsNumber(a) && IsNumber(b) {
-			if IsInteger(a) && IsInteger(b) {
-				li, _ := a.(int64)
-				ri, _ := b.(int64)
-				isLess = li < ri
-			} else {
-				isLess = numAsFloat(a) < numAsFloat(b)
-			}
-		} else {
-			var cmp int
-			if cmp, err = cmpAnyFract(a, b); err == nil {
-				isLess = cmp < 0
-			}
-		}
-	} else if IsString(a) && IsString(b) {
-		ls, _ := a.(string)
-		rs, _ := b.(string)
-		isLess = ls < rs
-		// Inclusion test
-	} else if IsList(a) && IsList(b) {
-		aList, _ := a.(*ListType)
-		bList, _ := b.(*ListType)
-		isLess = len(*aList) < len(*bList) && bList.contains(aList)
-	} else {
-		err = self.errIncompatibleTypes(a, b)
-	}
-	return
-}
-
-func evalLess(ctx ExprContext, opTerm *term) (v any, err error) {
 	var leftValue, rightValue any
 
-	if leftValue, rightValue, err = opTerm.evalInfix(ctx); err != nil {
+	if leftValue, rightValue, err = self.evalInfix(ctx); err != nil {
 		return
 	}
-	v, err = lessThan(opTerm, leftValue, rightValue)
+
+	if isNumber(leftValue) && isNumber(rightValue) {
+		if isInteger(leftValue) && isInteger(rightValue) {
+			li, _ := leftValue.(int64)
+			ri, _ := rightValue.(int64)
+			v = li < ri
+		} else {
+			v = numAsFloat(leftValue) < numAsFloat(rightValue)
+		}
+	} else if isString(leftValue) && isString(rightValue) {
+		ls, _ := leftValue.(string)
+		rs, _ := rightValue.(string)
+		v = ls < rs
+	} else {
+		err = self.errIncompatibleTypes(leftValue, rightValue)
+	}
 	return
 }
 
@@ -141,28 +141,28 @@ func newLessEqualTerm(tk *Token) (inst *term) {
 	}
 }
 
-func lessThanOrEqual(self *term, a, b any) (isLessEq bool, err error) {
+func evalLessEqual(ctx ExprContext, self *term) (v any, err error) {
-	if isLessEq, err = lessThan(self, a, b); err == nil {
-		if !isLessEq {
-			if IsList(a) && IsList(b) {
-				isLessEq, err = sameContent(a, b)
-			} else {
-				isLessEq, err = equals(a, b, nil)
-			}
-		}
-	}
-	return
-}
-
-func evalLessEqual(ctx ExprContext, opTerm *term) (v any, err error) {
 	var leftValue, rightValue any
 
-	if leftValue, rightValue, err = opTerm.evalInfix(ctx); err != nil {
+	if leftValue, rightValue, err = self.evalInfix(ctx); err != nil {
 		return
 	}
 
-	v, err = lessThanOrEqual(opTerm, leftValue, rightValue)
+	if isNumber(leftValue) && isNumber(rightValue) {
-
+		if isInteger(leftValue) && isInteger(rightValue) {
+			li, _ := leftValue.(int64)
+			ri, _ := rightValue.(int64)
+			v = li <= ri
+		} else {
+			v = numAsFloat(leftValue) <= numAsFloat(rightValue)
+		}
+	} else if isString(leftValue) && isString(rightValue) {
+		ls, _ := leftValue.(string)
+		rs, _ := rightValue.(string)
+		v = ls <= rs
+	} else {
+		err = self.errIncompatibleTypes(leftValue, rightValue)
+	}
 	return
 }
 
@@ -171,6 +171,8 @@ func evalLessEqual(ctx ExprContext, opTerm *term) (v any, err error) {
 func newGreaterTerm(tk *Token) (inst *term) {
 	return &term{
 		tk: *tk,
+		// class:    classOperator,
+		// kind:     kindBool,
 		children: make([]*term, 0, 2),
 		position: posInfix,
 		priority: priRelational,
@@ -178,14 +180,11 @@ func newGreaterTerm(tk *Token) (inst *term) {
 	}
 }
 
-func evalGreater(ctx ExprContext, opTerm *term) (v any, err error) {
+func evalGreater(ctx ExprContext, self *term) (v any, err error) {
-	var leftValue, rightValue any
+	if v, err = evalLessEqual(ctx, self); err == nil {
-
+		b, _ := toBool(v)
-	if leftValue, rightValue, err = opTerm.evalInfix(ctx); err != nil {
+		v = !b
-		return
 	}
-
-	v, err = lessThan(opTerm, rightValue, leftValue)
 	return
 }
 
@@ -194,6 +193,8 @@ func evalGreater(ctx ExprContext, opTerm *term) (v any, err error) {
 func newGreaterEqualTerm(tk *Token) (inst *term) {
 	return &term{
 		tk: *tk,
+		// class:    classOperator,
+		// kind:     kindBool,
 		children: make([]*term, 0, 2),
 		position: posInfix,
 		priority: priRelational,
@@ -201,14 +202,11 @@ func newGreaterEqualTerm(tk *Token) (inst *term) {
 	}
 }
 
-func evalGreaterEqual(ctx ExprContext, opTerm *term) (v any, err error) {
+func evalGreaterEqual(ctx ExprContext, self *term) (v any, err error) {
-	var leftValue, rightValue any
+	if v, err = evalLess(ctx, self); err == nil {
-
+		b, _ := toBool(v)
-	if leftValue, rightValue, err = opTerm.evalInfix(ctx); err != nil {
+		v = !b
-		return
 	}
-
-	v, err = lessThanOrEqual(opTerm, rightValue, leftValue)
 	return
 }
 

operator-selector.go

@@ -4,7 +4,65 @@
 // operator-selector.go
 package expr
 
-//-------- selector term
+// //-------- export all term
+
+// func newSelectorTerm(tk *Token) (inst *term) {
+// 	return &term{
+// 		tk:       *tk,
+// 		children: make([]*term, 0, 3),
+// 		position: posMultifix,
+// 		priority: priSelector,
+// 		evalFunc: evalSelector,
+// 	}
+// }
+
+// func isSelectorCase(ctx ExprContext, exprValue, caseSel any, caseIndex int) (selectedValue any, err error) {
+// 	caseData, _ := caseSel.(*selectorCase)
+// 	if caseData.filterList == nil {
+// 		selectedValue, err = caseData.caseExpr.eval(ctx, false)
+// 	} else {
+// 		filterList := caseData.filterList.children
+// 		if len(filterList) == 0 && exprValue == int64(caseIndex) {
+// 			selectedValue, err = caseData.caseExpr.eval(ctx, false)
+// 		} else {
+// 			var caseValue any
+// 			for _, caseTerm := range filterList {
+// 				if caseValue, err = caseTerm.compute(ctx); err != nil || caseValue == exprValue {
+// 					selectedValue, err = caseData.caseExpr.eval(ctx, false)
+// 					break
+// 				}
+// 			}
+// 		}
+// 	}
+// 	return
+// }
+
+// func evalSelector(ctx ExprContext, self *term) (v any, err error) {
+// 	var exprValue any
+// 	// var caseList []*term
+
+// 	if err = self.checkOperands(); err != nil {
+// 		return
+// 	}
+// 	exprTerm := self.children[0]
+// 	if exprValue, err = exprTerm.compute(ctx); err != nil {
+// 		return
+// 	}
+
+// 	caseList := self.children[1:]
+// 	for i, caseTerm := range caseList {
+// 		caseSel := caseTerm.value()
+// 		if v, err = isSelectorCase(ctx, exprValue, caseSel, i); err != nil || v != nil {
+// 			break
+// 		}
+// 	}
+// 	if err == nil && v == nil {
+// 		err = exprTerm.tk.Errorf("no case catches the value (%v) of the selection expression", exprValue)
+// 	}
+// 	return
+// }
+
+//-------- export all term
 
 func newSelectorTerm(tk *Token) (inst *term) {
 	return &term{
@@ -16,31 +74,18 @@ func newSelectorTerm(tk *Token) (inst *term) {
 	}
 }
 
-func trySelectorCase(ctx ExprContext, exprValue, caseSel any, caseIndex int) (match bool, selectedValue any, err error) {
+func isSelectorCase(ctx ExprContext, exprValue, caseSel any, caseIndex int) (selectedValue any, err error) {
 	caseData, _ := caseSel.(*selectorCase)
 	if caseData.filterList == nil {
-		selectedValue, err = caseData.caseExpr.Eval(ctx)
+		selectedValue, err = caseData.caseExpr.eval(ctx, false)
-		match = true
 	} else if filterList, ok := caseData.filterList.value().([]*term); ok {
-		if len(filterList) == 0 {
+		if len(filterList) == 0 && exprValue == int64(caseIndex) {
-			var valueAsInt = int64(0)
+			selectedValue, err = caseData.caseExpr.eval(ctx, false)
-			if b, ok := exprValue.(bool); ok {
-				if !b {
-					valueAsInt = 1
-				}
-			} else if valueAsInt, ok = exprValue.(int64); !ok {
-				return
-			}
-			if valueAsInt == int64(caseIndex) {
-				selectedValue, err = caseData.caseExpr.Eval(ctx)
-				match = true
-			}
 		} else {
 			var caseValue any
 			for _, caseTerm := range filterList {
 				if caseValue, err = caseTerm.compute(ctx); err != nil || caseValue == exprValue {
-					selectedValue, err = caseData.caseExpr.Eval(ctx)
+					selectedValue, err = caseData.caseExpr.eval(ctx, false)
-					match = true
 					break
 				}
 			}
@@ -49,27 +94,27 @@ func trySelectorCase(ctx ExprContext, exprValue, caseSel any, caseIndex int) (ma
 	return
 }
 
-func evalSelector(ctx ExprContext, opTerm *term) (v any, err error) {
+func evalSelector(ctx ExprContext, self *term) (v any, err error) {
 	var exprValue any
-	var match bool
+	// var caseList []*term
 
-	if err = opTerm.checkOperands(); err != nil {
+	if err = self.checkOperands(); err != nil {
 		return
 	}
-	exprTerm := opTerm.children[0]
+	exprTerm := self.children[0]
 	if exprValue, err = exprTerm.compute(ctx); err != nil {
 		return
 	}
 
-	caseListTerm := opTerm.children[1]
+	caseListTerm := self.children[1]
 	caseList, _ := caseListTerm.value().([]*term)
 	for i, caseTerm := range caseList {
 		caseSel := caseTerm.value()
-		if match, v, err = trySelectorCase(ctx, exprValue, caseSel, i); err != nil || match {
+		if v, err = isSelectorCase(ctx, exprValue, caseSel, i); err != nil || v != nil {
 			break
 		}
 	}
-	if err == nil && !match {
+	if err == nil && v == nil {
 		err = exprTerm.tk.Errorf("no case catches the value (%v) of the selection expression", exprValue)
 	}
 	return

operator-shift.go

@@ -1,77 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// operator-shift.go
-package expr
-
-//-------- bit right shift term
-
-func newRightShiftTerm(tk *Token) (inst *term) {
-	return &term{
-		tk:       *tk,
-		children: make([]*term, 0, 2),
-		position: posInfix,
-		priority: priBinShift,
-		evalFunc: evalRightShift,
-	}
-}
-
-func bitRightShift(opTerm *term, leftValue, rightValue any) (v any, err error) {
-	if IsInteger(leftValue) && IsInteger(rightValue) {
-		leftInt := leftValue.(int64)
-		rightInt := rightValue.(int64)
-		v = leftInt >> rightInt
-	} else {
-		err = opTerm.errIncompatibleTypes(leftValue, rightValue)
-	}
-	return
-}
-
-func evalRightShift(ctx ExprContext, opTerm *term) (v any, err error) {
-	var leftValue, rightValue any
-
-	if leftValue, rightValue, err = opTerm.evalInfix(ctx); err != nil {
-		return
-	}
-
-	v, err = bitRightShift(opTerm, leftValue, rightValue)
-	return
-}
-
-func newLeftShiftTerm(tk *Token) (inst *term) {
-	return &term{
-		tk:       *tk,
-		children: make([]*term, 0, 2),
-		position: posInfix,
-		priority: priBinShift,
-		evalFunc: evalLeftShift,
-	}
-}
-
-func bitLeftShift(opTerm *term, leftValue, rightValue any) (v any, err error) {
-	if IsInteger(leftValue) && IsInteger(rightValue) {
-		leftInt := leftValue.(int64)
-		rightInt := rightValue.(int64)
-		v = leftInt << rightInt
-	} else {
-		err = opTerm.errIncompatibleTypes(leftValue, rightValue)
-	}
-	return
-}
-
-func evalLeftShift(ctx ExprContext, opTerm *term) (v any, err error) {
-	var leftValue, rightValue any
-
-	if leftValue, rightValue, err = opTerm.evalInfix(ctx); err != nil {
-		return
-	}
-
-	v, err = bitLeftShift(opTerm, leftValue, rightValue)
-	return
-}
-
-// init
-func init() {
-	registerTermConstructor(SymDoubleGreater, newRightShiftTerm)
-	registerTermConstructor(SymDoubleLess, newLeftShiftTerm)
-}

operator-sign.go

@@ -28,29 +28,29 @@ func newMinusSignTerm(tk *Token) (inst *term) {
 	}
 }
 
-func evalSign(ctx ExprContext, opTerm *term) (v any, err error) {
+func evalSign(ctx ExprContext, self *term) (v any, err error) {
 	var rightValue any
 
-	if rightValue, err = opTerm.evalPrefix(ctx); err != nil {
+	if rightValue, err = self.evalPrefix(ctx); err != nil {
 		return
 	}
 
-	if IsFloat(rightValue) {
+	if isFloat(rightValue) {
-		if opTerm.tk.Sym == SymChangeSign {
+		if self.tk.Sym == SymChangeSign {
 			f, _ := rightValue.(float64)
 			v = -f
 		} else {
 			v = rightValue
 		}
-	} else if IsInteger(rightValue) {
+	} else if isInteger(rightValue) {
-		if opTerm.tk.Sym == SymChangeSign {
+		if self.tk.Sym == SymChangeSign {
 			i, _ := rightValue.(int64)
 			v = -i
 		} else {
 			v = rightValue
 		}
 	} else {
-		err = opTerm.errIncompatibleType(rightValue)
+		err = self.errIncompatibleType(rightValue)
 	}
 	return
 }

operator-sum.go

@@ -21,54 +21,44 @@ func newPlusTerm(tk *Token) (inst *term) {
 	}
 }
 
-func sumValues(plusTerm *term, leftValue, rightValue any) (v any, err error) {
+func evalPlus(ctx ExprContext, self *term) (v any, err error) {
-	if (IsString(leftValue) && isNumberString(rightValue)) || (IsString(rightValue) && isNumberString(leftValue)) {
+	var leftValue, rightValue any
+
+	if leftValue, rightValue, err = self.evalInfix(ctx); err != nil {
+		return
+	}
+
+	if (isString(leftValue) && isNumberString(rightValue)) || (isString(rightValue) && isNumberString(leftValue)) {
 		v = fmt.Sprintf("%v%v", leftValue, rightValue)
-	} else if IsNumber(leftValue) && IsNumber(rightValue) {
+	} else if isNumber(leftValue) && isNumber(rightValue) {
-		if IsFloat(leftValue) || IsFloat(rightValue) {
+		if isFloat(leftValue) || isFloat(rightValue) {
 			v = numAsFloat(leftValue) + numAsFloat(rightValue)
 		} else {
 			leftInt, _ := leftValue.(int64)
 			rightInt, _ := rightValue.(int64)
 			v = leftInt + rightInt
 		}
-	} else if IsList(leftValue) && IsList(rightValue) {
+	} else if isList(leftValue) || isList(rightValue) {
-		var leftList, rightList *ListType
+		var leftList, rightList []any
-		leftList, _ = leftValue.(*ListType)
+		var ok bool
-		rightList, _ = rightValue.(*ListType)
+		if leftList, ok = leftValue.([]any); !ok {
-
+			leftList = []any{leftValue}
-		sumList := make(ListType, 0, len(*leftList)+len(*rightList))
-		sumList = append(sumList, *leftList...)
-		sumList = append(sumList, *rightList...)
-		v = &sumList
-	} else if (isFraction(leftValue) && IsNumber(rightValue)) || (isFraction(rightValue) && IsNumber(leftValue)) {
-		if IsFloat(leftValue) || IsFloat(rightValue) {
-			v = numAsFloat(leftValue) + numAsFloat(rightValue)
-		} else {
-			v, err = sumAnyFract(leftValue, rightValue)
 		}
-	} else if IsDict(leftValue) && IsDict(rightValue) {
+		if rightList, ok = rightValue.([]any); !ok {
-		leftDict, _ := leftValue.(*DictType)
+			rightList = []any{rightValue}
-		rightDict, _ := rightValue.(*DictType)
+		}
-		c := leftDict.clone()
+		sumList := make([]any, 0, len(leftList)+len(rightList))
-		c.merge(rightDict)
+		for _, item := range leftList {
-		v = c
+			sumList = append(sumList, item)
-	} else if isFraction(leftValue) && isFraction(rightValue) {
+		}
-		v, err = sumAnyFract(leftValue, rightValue)
+		for _, item := range rightList {
-	} else {
+			sumList = append(sumList, item)
-		err = plusTerm.errIncompatibleTypes(leftValue, rightValue)
+		}
+		v = sumList
+	} else {
+		err = self.errIncompatibleTypes(leftValue, rightValue)
 	}
-	return v, err
-}
-
-func evalPlus(ctx ExprContext, plusTerm *term) (v any, err error) {
-	var leftValue, rightValue any
-
-	if leftValue, rightValue, err = plusTerm.evalInfix(ctx); err != nil {
 	return
-	}
-
-	return sumValues(plusTerm, leftValue, rightValue)
 }
 
 //-------- minus term
@@ -83,43 +73,37 @@ func newMinusTerm(tk *Token) (inst *term) {
 	}
 }
 
-func diffValues(minusTerm *term, leftValue, rightValue any) (v any, err error) {
+func evalMinus(ctx ExprContext, self *term) (v any, err error) {
-	if isNumOrFract(leftValue) && isNumOrFract(rightValue) {
+	var leftValue, rightValue any
-		if IsFloat(leftValue) || IsFloat(rightValue) {
+
+	if leftValue, rightValue, err = self.evalInfix(ctx); err != nil {
+		return
+	}
+
+	if isNumber(leftValue) && isNumber(rightValue) {
+		if isFloat(leftValue) || isFloat(rightValue) {
 			v = numAsFloat(leftValue) - numAsFloat(rightValue)
-		} else if isFraction(leftValue) || isFraction(rightValue) {
-			v, err = subAnyFract(leftValue, rightValue)
 		} else {
 			leftInt, _ := leftValue.(int64)
 			rightInt, _ := rightValue.(int64)
 			v = leftInt - rightInt
 		}
-	} else if IsList(leftValue) && IsList(rightValue) {
+	} else if isList(leftValue) && isList(rightValue) {
-		leftList, _ := leftValue.(*ListType)
+		leftList, _ := leftValue.([]any)
-		rightList, _ := rightValue.(*ListType)
+		rightList, _ := rightValue.([]any)
-		diffList := make(ListType, 0, len(*leftList)-len(*rightList))
+		diffList := make([]any, 0, len(leftList)-len(rightList))
-		for _, item := range *leftList {
+		for _, item := range leftList {
-			if slices.Index(*rightList, item) < 0 {
+			if slices.Index(rightList, item) < 0 {
 				diffList = append(diffList, item)
 			}
 		}
-		v = &diffList
+		v = diffList
 	} else {
-		err = minusTerm.errIncompatibleTypes(leftValue, rightValue)
+		err = self.errIncompatibleTypes(leftValue, rightValue)
 	}
 	return
 }
 
-func evalMinus(ctx ExprContext, minusTerm *term) (v any, err error) {
-	var leftValue, rightValue any
-
-	if leftValue, rightValue, err = minusTerm.evalInfix(ctx); err != nil {
-		return
-	}
-
-	return diffValues(minusTerm, leftValue, rightValue)
-}
-
 // init
 func init() {
 	registerTermConstructor(SymPlus, newPlusTerm)

operator-unset.go

@@ -1,69 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// operator-unset.go
-package expr
-
-import "strings"
-
-//-------- unset term
-
-func newUnsetTerm(tk *Token) (inst *term) {
-	return &term{
-		tk:       *tk,
-		children: make([]*term, 0, 1),
-		position: posPrefix,
-		priority: priSign,
-		evalFunc: evalUnset,
-	}
-}
-
-func deleteContextItem(ctx ExprContext, opTerm *term, item any) (deleted bool, err error) {
-	if name, ok := item.(string); ok {
-		var size int
-		if strings.HasSuffix(name, "()") {
-			size = ctx.FuncCount()
-			ctx.DeleteFunc(strings.TrimRight(name, "()"))
-			deleted = ctx.FuncCount() < size
-		} else {
-			size = ctx.VarCount()
-			ctx.DeleteVar(name)
-			deleted = ctx.VarCount() < size
-		}
-	} else {
-		err = opTerm.errIncompatibleType(item)
-	}
-	return
-}
-
-func evalUnset(ctx ExprContext, opTerm *term) (v any, err error) {
-	var childValue any
-	var deleted bool
-
-	if childValue, err = opTerm.evalPrefix(ctx); err != nil {
-		return
-	}
-
-	count := 0
-	if IsList(childValue) {
-		list, _ := childValue.(*ListType)
-		for _, item := range *list {
-			if deleted, err = deleteContextItem(ctx, opTerm, item); err != nil {
-				break
-			} else if deleted {
-				count++
-			}
-		}
-	} else if deleted, err = deleteContextItem(ctx, opTerm, childValue); err == nil && deleted {
-		count++
-	}
-	if err == nil {
-		v = int64(count)
-	}
-	return
-}
-
-// init
-func init() {
-	registerTermConstructor(SymKwUnset, newUnsetTerm)
-}

parser.go

@@ -6,83 +6,51 @@ package expr
 
 import (
 	"errors"
-
+	"fmt"
-	"golang.org/x/exp/constraints"
 )
 
 //-------- parser
 
-type parserContext uint16
-
-const (
-	parserNoFlags                = 0
-	allowMultiExpr parserContext = 1 << iota
-	allowVarRef
-	selectorContext
-	listContext                                // squareContext for list
-	indexContext                               // squareContext for index
-	allowIndex                                 // allow index in squareContext
-	squareContext = listContext | indexContext // Square parenthesis for list or index
-)
-
-func hasFlag[T constraints.Unsigned](set T, singleFlag T) bool {
-	return (set & singleFlag) != 0
-}
-
-func addFlags[T constraints.Unsigned](set T, flags T) T {
-	return set | flags
-}
-
-func addFlagsCond[T constraints.Unsigned](set T, flags T, cond bool) (newSet T) {
-	if cond {
-		newSet = set | flags
-	} else {
-		newSet = set
-	}
-	return
-}
-
-func remFlags[T constraints.Unsigned](set T, flags T) T {
-	return set & (^flags)
-}
-
 type parser struct {
+	ctx ExprContext
 }
 
-func NewParser() (p *parser) {
+func NewParser(ctx ExprContext) (p *parser) {
-	p = &parser{}
+	p = &parser{
+		ctx: ctx,
+	}
 	return p
 }
 
-func (parser *parser) Next(scanner *scanner) (tk *Token) {
+func (self *parser) parseFuncCall(scanner *scanner, allowVarRef bool, tk *Token) (tree *term, err error) {
-	for tk = scanner.Next(); tk.IsSymbol(SymComment); tk = scanner.Next() {
+	// name, _ := tk.Value.(string)
-	}
+	// funcObj := self.ctx.GetFuncInfo(name)
-	return
+	// if funcObj == nil {
-}
+	// 	err = fmt.Errorf("unknown function %s()", name)
-
+	// 	return
-func (parser *parser) parseFuncCall(scanner *scanner, ctx parserContext, tk *Token) (tree *term, err error) {
+	// }
+	// maxArgs := funcObj.MaxArgs()
+	// if maxArgs < 0 {
+	// 	maxArgs = funcObj.MinArgs() + 10
+	// }
+	// args := make([]*term, 0, maxArgs)
 	args := make([]*term, 0, 10)
-	itemExpected := false
 	lastSym := SymUnknown
 	for lastSym != SymClosedRound && lastSym != SymEos {
 		var subTree *ast
-		if subTree, err = parser.parseItem(scanner, ctx, SymComma, SymClosedRound); err != nil {
+		if subTree, err = self.parseItem(scanner, allowVarRef, SymComma, SymClosedRound); err == nil {
-			break
-		}
-		prev := scanner.Previous()
 			if subTree.root != nil {
 				args = append(args, subTree.root)
-		} else if itemExpected {
+			}
-			err = prev.ErrorExpectedGot("function-param-value")
+		} else {
 			break
 		}
-
-		itemExpected = prev.Sym == SymComma
 		lastSym = scanner.Previous().Sym
 	}
 	if err == nil {
+		// TODO Check arguments
 		if lastSym != SymClosedRound {
-			err = errors.New("unterminated arguments list")
+			err = errors.New("unterminate arguments list")
 		} else {
 			tree = newFuncCallTerm(tk, args)
 		}
@@ -90,60 +58,34 @@ func (parser *parser) parseFuncCall(scanner *scanner, ctx parserContext, tk *Tok
 	return
 }
 
-func (parser *parser) parseFuncDef(scanner *scanner) (tree *term, err error) {
+func (self *parser) parseFuncDef(scanner *scanner) (tree *term, err error) {
 	// Example: "add = func(x,y) {x+y}
 	var body *ast
 	args := make([]*term, 0)
-	lastSym := SymUnknown
+	tk := scanner.Next()
-	defaultParamsStarted := false
+	for tk.Sym != SymClosedRound && tk.Sym != SymEos {
-	itemExpected := false
+		if tk.Sym == SymIdentifier {
-	tk := scanner.Previous()
+			t := newTerm(tk, nil)
-	for lastSym != SymClosedRound && lastSym != SymEos {
+			args = append(args, t)
-		tk = parser.Next(scanner)
-		if tk.IsSymbol(SymIdentifier) {
-			param := newTerm(tk)
-			if len(args) > 0 {
-				if pos := paramAlreadyDefined(args, param); pos > 0 {
-					err = tk.Errorf("parameter %q at position %d already defined at position %d", param.source(), len(args)+1, pos)
-					break
-				}
-			}
-			args = append(args, param)
-			tk = parser.Next(scanner)
-			if tk.Sym == SymEqual {
-				var paramExpr *ast
-				defaultParamsStarted = true
-				if paramExpr, err = parser.parseItem(scanner, parserNoFlags, SymComma, SymClosedRound); err != nil {
-					break
-				}
-				param.forceChild(paramExpr.root)
-			} else if defaultParamsStarted {
-				err = tk.Errorf("can't mix default and non-default parameters")
-				break
-			}
-		} else if itemExpected {
-			prev := scanner.Previous()
-			err = prev.ErrorExpectedGot("function-param-spec")
-			break
-		}
-		lastSym = scanner.Previous().Sym
-		itemExpected = lastSym == SymComma
-	}
-
-	if err == nil && lastSym != SymClosedRound {
-		err = tk.ErrorExpectedGot(")")
-	}
-	if err == nil {
-		tk = parser.Next(scanner)
-		if tk.IsSymbol(SymOpenBrace) {
-			body, err = parser.parseGeneral(scanner, allowMultiExpr|allowVarRef, SymClosedBrace)
 		} else {
-			err = tk.ErrorExpectedGot("{")
+			err = tk.Errorf("invalid param %q, variable identifier expected", tk.source)
+			break
+		}
+		tk = scanner.Next()
+	}
+	if err == nil && tk.Sym != SymClosedRound {
+		err = tk.Errorf("unterminate function params list")
+	}
+	if err == nil {
+		tk = scanner.Next()
+		if tk.Sym == SymOpenBrace {
+			body, err = self.parseGeneral(scanner, true, true, SymClosedBrace)
 		}
 	}
 	if err == nil {
+		// TODO Check arguments
 		if scanner.Previous().Sym != SymClosedBrace {
-			err = scanner.Previous().ErrorExpectedGot("}")
+			err = scanner.Previous().Errorf("not properly terminated function body")
 		} else {
 			tk = scanner.makeValueToken(SymExpression, "", body)
 			tree = newFuncDefTerm(tk, args)
@@ -152,172 +94,35 @@ func (parser *parser) parseFuncDef(scanner *scanner) (tree *term, err error) {
 	return
 }
 
-func paramAlreadyDefined(args []*term, param *term) (position int) {
+func (self *parser) parseList(scanner *scanner, allowVarRef bool) (subtree *term, err error) {
-	position = 0
-	for i, arg := range args {
-		if arg.source() == param.source() {
-			position = i + 1
-		}
-	}
-	return
-}
-
-func (parser *parser) parseList(scanner *scanner, ctx parserContext) (listTerm *term, err error) {
-	r, c := scanner.lastPos()
 	args := make([]*term, 0)
 	lastSym := SymUnknown
-	itemExpected := false
-	itemCtx := remFlags(ctx, allowIndex)
 	for lastSym != SymClosedSquare && lastSym != SymEos {
-		zeroRequired := scanner.current.Sym == SymColon
-		var itemTree *ast
-		if itemTree, err = parser.parseItem(scanner, itemCtx, SymComma, SymClosedSquare); err == nil {
-			root := itemTree.root
-			if root != nil {
-				if hasFlag(ctx, allowIndex) && root.symbol() == SymColon {
-					changeColonToRange(root)
-				}
-				if !hasFlag(ctx, allowIndex) && root.symbol() == SymRange {
-					// err = root.Errorf("unexpected range expression")
-					err = errRangeUnexpectedExpression(root)
-					break
-				}
-				args = append(args, root)
-				if hasFlag(ctx, allowIndex) && root.symbol() == SymRange && zeroRequired { //len(root.children) == 0 {
-					if len(root.children) == 1 {
-						root.children = append(root.children, root.children[0])
-					} else if len(root.children) > 1 {
-						// err = root.Errorf("invalid range specification")
-						err = errRangeInvalidSpecification(root)
-						break
-					}
-					zeroTk := NewValueToken(root.tk.row, root.tk.col, SymInteger, "0", int64(0))
-					zeroTerm := newTerm(zeroTk)
-					zeroTerm.setParent(root)
-					root.children[0] = zeroTerm
-				}
-			} else if itemExpected {
-				prev := scanner.Previous()
-				err = prev.ErrorExpectedGot("list-item")
-				break
-			}
-		} else {
-			break
-		}
-		lastSym = scanner.Previous().Sym
-		if itemExpected = lastSym == SymComma; itemExpected {
-			remFlags(ctx, allowIndex)
-		}
-	}
-	if err == nil {
-		if lastSym != SymClosedSquare {
-			err = scanner.Previous().ErrorExpectedGot("]")
-		} else {
-			listTerm = newListTerm(r, c, args)
-		}
-	}
-	return
-}
-
-func (parser *parser) parseIterDef(scanner *scanner, ctx parserContext) (subtree *term, err error) {
-	tk := scanner.Previous()
-	args := make([]*term, 0)
-	lastSym := SymUnknown
-	itemExpected := false
-	for lastSym != SymClosedRound && lastSym != SymEos {
 		var subTree *ast
-		if subTree, err = parser.parseItem(scanner, ctx, SymComma, SymClosedRound); err == nil {
+		if subTree, err = self.parseItem(scanner, allowVarRef, SymComma, SymClosedSquare); err == nil {
 			if subTree.root != nil {
 				args = append(args, subTree.root)
-			} else if itemExpected {
-				prev := scanner.Previous()
-				err = prev.ErrorExpectedGot("iterator-param")
-				break
 			}
 		} else {
 			break
 		}
 		lastSym = scanner.Previous().Sym
-		itemExpected = lastSym == SymComma
 	}
 	if err == nil {
-		if lastSym != SymClosedRound {
+		// TODO Check arguments
-			err = scanner.Previous().ErrorExpectedGot(")")
+		if lastSym != SymClosedSquare {
+			err = scanner.Previous().Errorf("unterminate items list")
 		} else {
-			subtree = newIteratorTerm(tk, args)
+			subtree = newListTerm(args)
 		}
 	}
 	return
 }
 
-func (parser *parser) parseDictKey(scanner *scanner) (key any, err error) {
+func (self *parser) parseSelectorCase(scanner *scanner, allowVarRef bool, defaultCase bool) (caseTerm *term, err error) {
-	tk := parser.Next(scanner)
-	if tk.Sym == SymError {
-		err = tk.Error()
-		return
-	}
-	if tk.Sym == SymClosedBrace || tk.Sym == SymEos {
-		return
-	}
-	if tk.Sym == SymInteger || tk.Sym == SymString {
-		tkSep := parser.Next(scanner)
-		if tkSep.Sym != SymColon {
-			err = tkSep.ErrorExpectedGot(":")
-		} else {
-			key = tk.Value
-		}
-	} else {
-		err = tk.ErrorExpectedGot("dictionary-key or }")
-	}
-	return
-}
-
-func (parser *parser) parseDictionary(scanner *scanner, ctx parserContext) (subtree *term, err error) {
-	args := make(map[any]*term, 0)
-	lastSym := SymUnknown
-	itemExpected := false
-	for lastSym != SymClosedBrace && lastSym != SymEos {
-		var subTree *ast
-		var key any
-		if key, err = parser.parseDictKey(scanner); err != nil {
-			break
-		} else if key == nil {
-			tk := scanner.Previous()
-			lastSym = tk.Sym
-			if itemExpected {
-				err = tk.ErrorExpectedGot("dictionary-key")
-			}
-			break
-		}
-		if subTree, err = parser.parseItem(scanner, ctx, SymComma, SymClosedBrace); err == nil {
-			if subTree.root != nil {
-				args[key] = subTree.root
-			} else /*if key != nil*/ {
-				prev := scanner.Previous()
-				err = prev.ErrorExpectedGot("dictionary-value")
-				break
-			}
-		} else {
-			break
-		}
-		lastSym = scanner.Previous().Sym
-		itemExpected = lastSym == SymComma
-	}
-	if err == nil {
-		if lastSym != SymClosedBrace {
-			err = scanner.Previous().ErrorExpectedGot("}")
-		} else {
-			subtree = newDictTerm(args)
-		}
-	}
-	return
-}
-
-func (parser *parser) parseSelectorCase(scanner *scanner, ctx parserContext, defaultCase bool) (caseTerm *term, err error) {
 	var filterList *term
 	var caseExpr *ast
-	ctx = remFlags(ctx, allowIndex)
+	tk := scanner.Next()
-	tk := parser.Next(scanner)
 	startRow := tk.row
 	startCol := tk.col
 	if tk.Sym == SymOpenSquare {
@@ -325,22 +130,22 @@ func (parser *parser) parseSelectorCase(scanner *scanner, ctx parserContext, def
 			err = tk.Errorf("case list in default clause")
 			return
 		}
-		if filterList, err = parser.parseList(scanner, remFlags(ctx, allowIndex)); err != nil {
+		if filterList, err = self.parseList(scanner, allowVarRef); err != nil {
 			return
 		}
-		tk = parser.Next(scanner)
+		tk = scanner.Next()
 		startRow = tk.row
 		startCol = tk.col
 	} else if !defaultCase {
-		filterList = newListTerm(startRow, startCol, make([]*term, 0))
+		filterList = newListTerm(make([]*term, 0))
 	}
 
 	if tk.Sym == SymOpenBrace {
-		if caseExpr, err = parser.parseGeneral(scanner, ctx|allowMultiExpr, SymClosedBrace); err != nil {
+		if caseExpr, err = self.parseGeneral(scanner, true, allowVarRef, SymClosedBrace); err != nil {
 			return
 		}
 	} else {
-		err = tk.ErrorExpectedGot("{")
+		err = tk.Errorf("selector-case expected, got %q", tk.source)
 	}
 
 	if err == nil {
@@ -362,89 +167,43 @@ func addSelectorCase(selectorTerm, caseTerm *term) {
 	caseTerm.parent = selectorTerm
 }
 
-func (parser *parser) parseSelector(scanner *scanner, tree *ast, ctx parserContext) (selectorTerm *term, err error) {
+func (self *parser) parseSelector(scanner *scanner, tree *ast, allowVarRef bool) (selectorTerm *term, err error) {
 	var caseTerm *term
-
-	ctx = remFlags(ctx, allowIndex)
 	tk := scanner.makeToken(SymSelector, '?')
-	if selectorTerm, err = tree.addToken(tk); err != nil {
+	if selectorTerm, err = tree.addToken2(tk); err != nil {
 		return
 	}
 
-	if caseTerm, err = parser.parseSelectorCase(scanner, ctx|allowVarRef, false); err == nil {
+	if caseTerm, err = self.parseSelectorCase(scanner, allowVarRef, false); err == nil {
 		addSelectorCase(selectorTerm, caseTerm)
 	}
 	return
 }
 
-func (parser *parser) parseItem(scanner *scanner, ctx parserContext, termSymbols ...Symbol) (tree *ast, err error) {
+func (self *parser) parseItem(scanner *scanner, allowVarRef bool, termSymbols ...Symbol) (tree *ast, err error) {
-	return parser.parseGeneral(scanner, ctx|allowVarRef, termSymbols...)
+	return self.parseGeneral(scanner, false, allowVarRef, termSymbols...)
 }
 
-func (parser *parser) Parse(scanner *scanner, termSymbols ...Symbol) (tree *ast, err error) {
+func (self *parser) Parse(scanner *scanner, termSymbols ...Symbol) (tree *ast, err error) {
-	termSymbols = append(termSymbols, SymEos)
+	return self.parseGeneral(scanner, true, false, termSymbols...)
-	return parser.parseGeneral(scanner, allowMultiExpr, termSymbols...)
 }
 
-func couldBeACollection(t *term) bool {
+func (self *parser) parseGeneral(scanner *scanner, allowForest bool, allowVarRef bool, termSymbols ...Symbol) (tree *ast, err error) {
-	var sym = SymUnknown
-	if t != nil {
-		sym = t.symbol()
-	}
-	return sym == SymList || sym == SymString || sym == SymDict || sym == SymExpression || sym == SymVariable
-}
-
-func listSubTree(tree *ast, listTerm *term, allowIndeces bool) (root *term, err error) {
-	var tk *Token
-	if allowIndeces {
-		tk = NewToken(listTerm.tk.row, listTerm.tk.col, SymIndex, listTerm.source())
-		root = newTerm(tk)
-		if err = tree.addTerm(root); err == nil {
-			err = tree.addTerm(listTerm)
-		}
-	} else {
-		root = listTerm
-		err = tree.addTerm(listTerm)
-	}
-	return
-}
-
-func changePrefix(tk *Token) {
-	switch tk.Sym {
-	case SymMinus:
-		tk.SetSymbol(SymChangeSign)
-	case SymPlus:
-		tk.SetSymbol(SymUnchangeSign)
-	case SymStar:
-		tk.SetSymbol(SymDereference)
-	case SymExclamation:
-		tk.SetSymbol(SymNot)
-	case SymDoublePlus:
-		tk.SetSymbol(SymPreInc)
-	case SymDoubleMinus:
-		tk.SetSymbol(SymPreDec)
-	}
-}
-
-func (parser *parser) parseGeneral(scanner *scanner, ctx parserContext, termSymbols ...Symbol) (tree *ast, err error) {
 	var selectorTerm *term = nil
 	var currentTerm *term = nil
 	var tk *Token
-
 	tree = NewAst()
 	firstToken := true
-	// lastSym := SymUnknown
+	lastSym := SymUnknown
-	for tk = parser.Next(scanner); err == nil && tk != nil && !tk.IsTerm(termSymbols); /*&& !areSymbolsOutOfCtx(tk, selectorTerm, SymColon, SymDoubleColon)*/ tk = parser.Next(scanner) {
+	for tk = scanner.Next(); err == nil && tk != nil && !tk.IsTerm(termSymbols); tk = scanner.Next() {
-		// if tk.Sym == SymComment {
+		if tk.Sym == SymComment {
-		// 	continue
+			continue
-		// }
+		}
 
 		if tk.Sym == SymSemiColon {
-			if hasFlag(ctx, allowMultiExpr) {
+			if allowForest {
 				tree.ToForest()
 				firstToken = true
-				currentTerm = nil
-				selectorTerm = nil
 				continue
 			} else {
 				err = tk.Errorf(`unexpected token %q, expected ",", "]", or ")"`, tk.source)
@@ -454,118 +213,84 @@ func (parser *parser) parseGeneral(scanner *scanner, ctx parserContext, termSymb
 
 		//fmt.Println("Token:", tk)
 		if firstToken {
-			changePrefix(tk)
+			if tk.Sym == SymMinus {
-			// if tk.Sym == SymMinus {
+				tk.Sym = SymChangeSign
-			// 	tk.Sym = SymChangeSign
+			} else if tk.Sym == SymPlus {
-			// } else if tk.Sym == SymPlus {
+				tk.Sym = SymUnchangeSign
-			// 	tk.Sym = SymUnchangeSign
+			}
-			// } else if tk.IsSymbol(SymStar) {
-			// 	tk.SetSymbol(SymDereference)
-			// } else if tk.IsSymbol(SymExclamation) {
-			// 	tk.SetSymbol(SymNot)
-			// }
 			firstToken = false
 		}
 
 		switch tk.Sym {
 		case SymOpenRound:
 			var subTree *ast
-			if subTree, err = parser.parseGeneral(scanner, ctx, SymClosedRound); err == nil {
+			if subTree, err = self.parseGeneral(scanner, false, allowVarRef, SymClosedRound); err == nil {
-				exprTerm := newExprTerm(subTree.root)
+				subTree.root.priority = priValue
-				err = tree.addTerm(exprTerm)
+				err = tree.addTerm(subTree.root)
-				currentTerm = exprTerm
+				currentTerm = subTree.root
-				// subTree.root.priority = priValue
-				// err = tree.addTerm(newExprTerm(subTree.root))
-				// currentTerm = subTree.root
 			}
 		case SymFuncCall:
 			var funcCallTerm *term
-			if funcCallTerm, err = parser.parseFuncCall(scanner, ctx, tk); err == nil {
+			if funcCallTerm, err = self.parseFuncCall(scanner, allowVarRef, tk); err == nil {
 				err = tree.addTerm(funcCallTerm)
 				currentTerm = funcCallTerm
 			}
 		case SymOpenSquare:
 			var listTerm *term
-			newCtx := addFlagsCond(addFlags(ctx, squareContext), allowIndex, couldBeACollection(currentTerm))
+			if listTerm, err = self.parseList(scanner, allowVarRef); err == nil {
-			if listTerm, err = parser.parseList(scanner, newCtx); err == nil {
+				err = tree.addTerm(listTerm)
-				currentTerm, err = listSubTree(tree, listTerm, hasFlag(newCtx, allowIndex))
+				currentTerm = listTerm
 			}
-		case SymOpenBrace:
+		case SymEqual:
-			if currentTerm != nil && currentTerm.symbol() == SymColon {
+			if err = checkPrevSymbol(lastSym, SymIdentifier, tk); err == nil {
-				err = currentTerm.Errorf(`selector-case outside of a selector context`)
+				currentTerm, err = tree.addToken2(tk)
-			} else {
-				var mapTerm *term
-				if mapTerm, err = parser.parseDictionary(scanner, ctx); err == nil {
-					err = tree.addTerm(mapTerm)
-					currentTerm = mapTerm
 			}
-			}
-		case SymEqual, SymPlusEqual, SymMinusEqual, SymStarEqual, SymSlashEqual, SymPercEqual, SymAmpersandEqual, SymVertBarEqual, SymDoubleLessEqual, SymDoubleGreaterEqual, SymCaretEqual:
-			currentTerm, err = tree.addToken(tk)
-			firstToken = true
 		case SymFuncDef:
 			var funcDefTerm *term
-			if funcDefTerm, err = parser.parseFuncDef(scanner); err == nil {
+			if funcDefTerm, err = self.parseFuncDef(scanner); err == nil {
 				err = tree.addTerm(funcDefTerm)
 				currentTerm = funcDefTerm
 			}
-		case SymDollarRound:
-			var iterDefTerm *term
-			if iterDefTerm, err = parser.parseIterDef(scanner, ctx); err == nil {
-				err = tree.addTerm(iterDefTerm)
-				currentTerm = iterDefTerm
-			}
 		case SymIdentifier:
-			if tk.source[0] == '@' && !hasFlag(ctx, allowVarRef) {
+			if tk.source[0] == '@' && !allowVarRef {
 				err = tk.Errorf("variable references are not allowed in top level expressions: %q", tk.source)
 			} else {
-				currentTerm, err = tree.addToken(tk)
+				currentTerm, err = tree.addToken2(tk)
 			}
 		case SymQuestion:
-			if selectorTerm, err = parser.parseSelector(scanner, tree, ctx); err == nil {
+			if selectorTerm, err = self.parseSelector(scanner, tree, allowVarRef); err == nil {
 				currentTerm = selectorTerm
-				addFlags(ctx, selectorContext)
 			}
 		case SymColon, SymDoubleColon:
 			var caseTerm *term
-			if selectorTerm != nil {
+			if selectorTerm == nil {
-				if caseTerm, err = parser.parseSelectorCase(scanner, ctx, tk.Sym == SymDoubleColon); err == nil {
+				err = tk.Errorf("selector-case outside of a selector context")
+			} else if caseTerm, err = self.parseSelectorCase(scanner, allowVarRef, tk.Sym == SymDoubleColon); err == nil {
 				addSelectorCase(selectorTerm, caseTerm)
 				currentTerm = caseTerm
 				if tk.Sym == SymDoubleColon {
 					selectorTerm = nil
 				}
 			}
-			} else {
-				currentTerm, err = tree.addToken(tk)
-				if tk.IsOneOfA(SymColon, SymRange) {
-					// Colon outside a selector term acts like a separator
-					firstToken = true
-				}
-			}
 		default:
-			currentTerm, err = tree.addToken(tk)
+			currentTerm, err = tree.addToken2(tk)
 		}
 
 		if currentTerm != nil && currentTerm.tk.Sym != SymSelector && currentTerm.parent != nil && currentTerm.parent.tk.Sym != SymSelector {
 			selectorTerm = nil
-			remFlags(ctx, selectorContext)
-		}
-		// lastSym = tk.Sym
-	}
 
+		}
+		lastSym = tk.Sym
+	}
 	if err == nil {
-		if !tk.IsOneOf(termSymbols) {
-			var symDesc string
-			if tk.IsSymbol(SymError) {
-				symDesc = tk.ErrorText()
-			} else {
-				symDesc = SymToString(tk.Sym)
-			}
-			err = tk.ErrorExpectedGotStringWithPrefix("expected one of", SymListToString(termSymbols, true), symDesc)
-		} else {
 		err = tk.Error()
 	}
-	}
+	return
+}
+
+func checkPrevSymbol(lastSym, wantedSym Symbol, tk *Token) (err error) {
+	if lastSym != wantedSym {
+		err = fmt.Errorf(`assign operator (%q) must be preceded by a variable`, tk.source)
+	}
 	return
 }

parser_test.go

@@ -0,0 +1,317 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
+// parser_test.go
+package expr
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+	"testing"
+)
+
+func TestParser(t *testing.T) {
+	type inputType struct {
+		source     string
+		wantResult any
+		wantErr    error
+	}
+
+	inputs := []inputType{
+		/*   1 */ {`1+/*5*/2`, int64(3), nil},
+		/*   2 */ {`3 == 4`, false, nil},
+		/*   3 */ {`3 != 4`, true, nil},
+		/*   4 */ {`4 == (3-1)*(10/5)`, true, nil},
+		/*   5 */ {`3 <= 4`, true, nil},
+		/*   6 */ {`3 < 4`, true, nil},
+		/*   7 */ {`4 < 3`, false, nil},
+		/*   8 */ {`1+5 < 4`, false, nil},
+		/*   9 */ {`3 > 4`, false, nil},
+		/*  10 */ {`4 >= 4`, true, nil},
+		/*  11 */ {`4 > 3`, true, nil},
+		/*  12 */ {`1+5 > 4`, true, nil},
+		/*  13 */ {`true`, true, nil},
+		/*  14 */ {`not true`, false, nil},
+		/*  15 */ {`true and false`, false, nil},
+		/*  16 */ {`true or false`, true, nil},
+		/*  17 */ {`"uno" + "due"`, `unodue`, nil},
+		/*  18 */ {`"uno" + 2`, `uno2`, nil},
+		/*  19 */ {`"uno" + (2+1)`, `uno3`, nil},
+		/*  20 */ {`"uno" * (2+1)`, `unounouno`, nil},
+		/*  21 */ {"1", int64(1), nil},
+		/*  22 */ {"1.5", float64(1.5), nil},
+		/*  23 */ {"1.5*2", float64(3.0), nil},
+		/*  24 */ {"+1", int64(1), nil},
+		/*  25 */ {"-1", int64(-1), nil},
+		/*  26 */ {"435 + 105 * 2 - 1", int64(644), nil},
+		/*  27 */ {"200 / 2 - 1", int64(99), nil},
+		/*  28 */ {"(1+1)", int64(2), nil},
+		/*  29 */ {"-(1+1)", int64(-2), nil},
+		/*  30 */ {"-(-2+1)", int64(1), nil},
+		/*  31 */ {"(1+1)*5", int64(10), nil},
+		/*  32 */ {"200 / (1+1) - 1", int64(99), nil},
+		/*  33 */ {`add(1,2,3)`, int64(6), nil},
+		/*  34 */ {`mulX(1,2,3)`, nil, errors.New(`unknown function mulX()`)},
+		/*  35 */ {`add(1+4,3+2,5*(3-2))`, int64(15), nil},
+		/*  36 */ {`add(add(1+4),3+2,5*(3-2))`, int64(15), nil},
+		/*  37 */ {`add(add(1,4),/*3+2,*/5*(3-2))`, int64(10), nil},
+		/*  38 */ {`1+(1+(1+(1)+1)+1)+1`, int64(7), nil},
+		/*  39 */ {`(((1)))`, int64(1), nil},
+		/*  40 */ {`"uno_" + var2`, `uno_abc`, nil},
+		/*  41 */ {`0 || 0.0 && "hello"`, false, nil},
+		/*  42 */ {`"s" + true`, nil, errors.New(`[1:6] left operand 's' [string] and right operand 'true' [bool] are not compatible with operator "+"`)},
+		/*  43 */ {`+false`, nil, errors.New(`[1:2] prefix/postfix operator "+" do not support operand 'false' [bool]`)},
+		/*  44 */ {`false // very simple expression`, false, nil},
+		/*  45 */ {`1 + // Missing right operator`, nil, errors.New(`[1:4] infix operator "+" requires two not nil operands, got 1`)},
+		/*  46 */ {"", nil, errors.New(`empty expression`)},
+		/*  47 */ {"4!", int64(24), nil},
+		/*  48 */ {"(-4)!", nil, errors.New(`factorial of a negative integer (-4) is not allowed`)},
+		/*  49 */ {"-4!", int64(-24), nil},
+		/*  50 */ {"1.5 < 7", true, nil},
+		/*  51 */ {"1.5 > 7", false, nil},
+		/*  52 */ {"1.5 <= 7", true, nil},
+		/*  53 */ {"1.5 >= 7", false, nil},
+		/*  54 */ {"1.5 != 7", true, nil},
+		/*  55 */ {"1.5 == 7", false, nil},
+		/*  56 */ {`"1.5" < "7"`, true, nil},
+		/*  57 */ {`"1.5" > "7"`, false, nil},
+		/*  58 */ {`"1.5" == "7"`, false, nil},
+		/*  59 */ {`"1.5" != "7"`, true, nil},
+		/*  60 */ {"1.5 < ", nil, errors.New(`[1:6] infix operator "<" requires two not nil operands, got 1`)},
+		/*  61 */ {"1.5 > ", nil, errors.New(`[1:6] infix operator ">" requires two not nil operands, got 1`)},
+		/*  62 */ {"1.5 <= ", nil, errors.New(`[1:6] infix operator "<=" requires two not nil operands, got 1`)},
+		/*  63 */ {"1.5 >= ", nil, errors.New(`[1:6] infix operator ">=" requires two not nil operands, got 1`)},
+		/*  64 */ {"1.5 != ", nil, errors.New(`[1:6] infix operator "!=" requires two not nil operands, got 1`)},
+		/*  65 */ {"1.5 == ", nil, errors.New(`[1:6] infix operator "==" requires two not nil operands, got 1`)},
+		/*  66 */ {`"1.5" < `, nil, errors.New(`[1:8] infix operator "<" requires two not nil operands, got 1`)},
+		/*  67 */ {`"1.5" > `, nil, errors.New(`[1:8] infix operator ">" requires two not nil operands, got 1`)},
+		/*  68 */ {`"1.5" == `, nil, errors.New(`[1:8] infix operator "==" requires two not nil operands, got 1`)},
+		/*  69 */ {`"1.5" != `, nil, errors.New(`[1:8] infix operator "!=" requires two not nil operands, got 1`)},
+		/*  70 */ {"+1.5", float64(1.5), nil},
+		/*  71 */ {"+", nil, errors.New(`[1:2] prefix operator "+" requires one not nil operand`)},
+		/*  72 */ {"4 / 0", nil, errors.New(`division by zero`)},
+		/*  73 */ {"4.0 / 0", nil, errors.New(`division by zero`)},
+		/*  74 */ {"4.0 / \n2", float64(2.0), nil},
+		/*  75 */ {`123`, int64(123), nil},
+		/*  76 */ {`1.`, float64(1.0), nil},
+		/*  77 */ {`1.E-2`, float64(0.01), nil},
+		/*  78 */ {`1E2`, float64(100), nil},
+		/*  79 */ {`1 / 2`, int64(0), nil},
+		/*  80 */ {`1.0 / 2`, float64(0.5), nil},
+		/*  81 */ {`1 ./ 2`, float64(0.5), nil},
+		/*  82 */ {`5 % 2`, int64(1), nil},
+		/*  83 */ {`5 % (-2)`, int64(1), nil},
+		/*  84 */ {`-5 % 2`, int64(-1), nil},
+		/*  85 */ {`5 % 2.0`, nil, errors.New(`[1:4] left operand '5' [int64] and right operand '2' [float64] are not compatible with operator "%"`)},
+		/*  86 */ {`"a" < "b" AND NOT (2 < 1)`, true, nil},
+		/*  87 */ {`"a" < "b" AND NOT (2 == 1)`, true, nil},
+		/*  88 */ {`"a" < "b" AND ~ 2 == 1`, true, nil},
+		/*  89 */ {`~ 2 > 1`, false, nil},
+		/*  90 */ {`~ true && true`, false, nil},
+		/*  91 */ {`~ false || true`, true, nil},
+		/*  92 */ {`false but true`, true, nil},
+		/*  93 */ {`2+3 but 5*2`, int64(10), nil},
+		/*  94 */ {`add(1,2) but var2`, "abc", nil},
+		/*  95 */ {`x=2`, int64(2), nil},
+		/*  96 */ {`x=2 but x*10`, int64(20), nil},
+		/*  97 */ {`false and true`, false, nil},
+		/*  98 */ {`false and (x==2)`, false, nil},
+		/*  99 */ {`false and (x=2 but x==2) or x==2`, nil, errors.New(`undefined variable "x"`)},
+		/* 100 */ {`false or true`, true, nil},
+		/* 101 */ {`false or (x==2)`, nil, errors.New(`undefined variable "x"`)},
+		/* 102 */ {`a=5; a`, int64(5), nil},
+		/* 103 */ {`a=5; b=2; add(a, b*3)`, int64(11), nil},
+		/* 104 */ {`2=5`, nil, errors.New(`assign operator ("=") must be preceded by a variable`)},
+		/* 105 */ {`2+a=5`, nil, errors.New(`[1:3] left operand of "=" must be a variable`)},
+		/* 106 */ {`2+(a=5)`, int64(7), nil},
+		/* 107 */ {`two=func(){2}; two()`, int64(2), nil},
+		/* 108 */ {`double=func(x) {2*x}; (double(3))`, int64(6), nil},
+		/* 109 */ {`double=func(x){2*x}; double(3)`, int64(6), nil},
+		/* 110 */ {`double=func(x){2*x}; a=5; double(3+a) + 1`, int64(17), nil},
+		/* 111 */ {`double=func(x){2*x}; a=5; two=func() {2}; (double(3+a) + 1) * two()`, int64(34), nil},
+		/* 112 */ {`import("./test-funcs.expr"); (double(3+a) + 1) * two()`, int64(34), nil},
+		/* 113 */ {`import("test-funcs.expr"); (double(3+a) + 1) * two()`, int64(34), nil},
+		/* 114 */ {`x ?? "default"`, "default", nil},
+		/* 115 */ {`x="hello"; x ?? "default"`, "hello", nil},
+		/* 116 */ {`x ?? func(){}"`, nil, errors.New(`[1:15] the right operand of a coalescing operation cannot be a function definition`)},
+		/* 117 */ {`x ?= "default"; x`, "default", nil},
+		/* 118 */ {`x="hello"; x ?= "default"; x`, "hello", nil},
+		/* 119 */ {`@x="hello"; @x`, nil, errors.New(`[1:3] variable references are not allowed in top level expressions: "@x"`)},
+		/* 120 */ {`f=func(){@x="hello"}; f(); x`, "hello", nil},
+		/* 121 */ {`f=func(@y){@y=@y+1}; f(2); y`, int64(3), nil},
+		/* 122 */ {`f=func(@y){g=func(){@x=5}; @y=@y+g()}; f(2); y+x`, nil, errors.New(`undefined variable "x"`)},
+		/* 123 */ {`f=func(@y){g=func(){@x=5}; @z=g(); @y=@y+@z}; f(2); y+z`, int64(12), nil},
+		/* 124 */ {`f=func(@y){g=func(){@x=5}; g(); @z=x; @y=@y+@z}; f(2); y+z`, int64(12), nil},
+		/* 125 */ {`f=func(@y){g=func(){@x=5}; g(); @z=x; @x=@y+@z}; f(2); y+x`, int64(9), nil},
+		/* 126 */ {`include("./test-funcs.expr"); six()`, int64(6), nil},
+		/* 127 */ {`import("./sample-export-all.expr"); six()`, int64(6), nil},
+		/* 128 */ {`1 ? {"a"} : {"b"}`, "b", nil},
+		/* 129 */ {`10 ? {"a"} : {"b"} :: {"c"}`, "c", nil},
+		/* 130 */ {`10 ? {"a"} :[true, 2+8] {"b"} :: {"c"}`, "b", nil},
+		/* 131 */ {`10 ? {"a"} :[true, 2+8] {"b"} ::[10] {"c"}`, nil, errors.New(`[1:34] case list in default clause`)},
+		/* 132 */ {`10 ? {"a"} :[10] {x="b" but x} :: {"c"}`, "b", nil},
+		/* 133 */ {`10 ? {"a"} :[10] {x="b"; x} :: {"c"}`, "b", nil},
+		/* 134 */ {`10 ? {"a"} : {"b"}`, nil, errors.New(`[1:3] no case catches the value (10) of the selection expression`)},
+		/* 135 */ {`10 ? {"a"} :: {"b"} : {"c"}`, nil, errors.New(`[1:22] selector-case outside of a selector context`)},
+		/* 136 */ {`1 ? {"a"} : {"b"} ? ["a"] {"A"} :["b"] {"B"}`, "B", nil},
+		/* 137 */ {`2 + 1 ? {"a"} : {"b"} * 3`, "2bbb", nil},
+	}
+	check_env_expr_path := 113
+
+	succeeded := 0
+	failed := 0
+
+	// inputs1 := []inputType{
+	// 	{`10 ? {"a"} :[true, 2+8] {"b"} :: {"c"}`, "b", nil},
+	// }
+
+	for i, input := range inputs {
+		var expr Expr
+		var gotResult any
+		var gotErr error
+
+		ctx := NewSimpleFuncStore()
+		ctx.SetVar("var1", int64(123))
+		ctx.SetVar("var2", "abc")
+		ImportMathFuncs(ctx)
+		ImportImportFuncs(ctx)
+		parser := NewParser(ctx)
+
+		logTest(t, i+1, input.source, input.wantResult, input.wantErr)
+
+		r := strings.NewReader(input.source)
+		scanner := NewScanner(r, DefaultTranslations())
+
+		good := true
+		if expr, gotErr = parser.Parse(scanner); gotErr == nil {
+			gotResult, gotErr = expr.Eval(ctx)
+		}
+
+		if gotResult != input.wantResult {
+			t.Errorf("%d: %q -> result = %v [%T], want %v [%T]", i+1, input.source, gotResult, gotResult, input.wantResult, input.wantResult)
+			good = false
+		}
+
+		if gotErr != input.wantErr {
+			if input.wantErr == nil || gotErr == nil || (gotErr.Error() != input.wantErr.Error()) {
+				t.Errorf("%d: %q -> err = <%v>, want <%v>", i+1, input.source, gotErr, input.wantErr)
+				good = false
+			}
+		}
+
+		if good {
+			succeeded++
+		} else {
+			failed++
+			if i+1 == check_env_expr_path {
+				t.Logf(`NOTICE: Test nr %d requires EXPR_PATH="."`, check_env_expr_path)
+			}
+		}
+	}
+	t.Log(fmt.Sprintf("test count: %d, succeeded count: %d, failed count: %d", len(inputs), succeeded, failed))
+}
+
+func TestListParser(t *testing.T) {
+	type inputType struct {
+		source     string
+		wantResult any
+		wantErr    error
+	}
+
+	// inputs1 := []inputType{
+	// 	{`add(1,2,3)`, int64(6), nil},
+	// }
+
+	inputs := []inputType{
+		/*  1 */ {`[]`, []any{}, nil},
+		/*  2 */ {`[1,2,3]`, []any{int64(1), int64(2), int64(3)}, nil},
+		/*  3 */ {`[1,2,"hello"]`, []any{int64(1), int64(2), "hello"}, nil},
+		/*  4 */ {`[1+2, not true, "hello"]`, []any{int64(3), false, "hello"}, nil},
+		/*  5 */ {`[1,2]+[3]`, []any{int64(1), int64(2), int64(3)}, nil},
+		/*  6 */ {`[1,4,3,2]-[3]`, []any{int64(1), int64(4), int64(2)}, nil},
+		/*  7 */ {`add([1,4,3,2])`, int64(10), nil},
+		/*  8 */ {`add([1,[2,2],3,2])`, int64(10), nil},
+		/*  9 */ {`mul([1,4,3.0,2])`, float64(24.0), nil},
+		/* 10 */ {`add([1,"hello"])`, nil, errors.New(`add(): param nr 2 has wrong type string, number expected`)},
+		/* 11 */ {`[a=1,b=2,c=3] but a+b+c`, int64(6), nil},
+		// /*  8 */ {`[int(x)|x=csv("test.csv",1,all(),1)]`, []any{int64(10), int64(40), int64(20)}, nil},
+		// /*  9 */ {`sum(@[int(x)|x=csv("test.csv",1,all(),1)])`, []any{int64(10), int64(40), int64(20)}, nil},
+	}
+
+	succeeded := 0
+	failed := 0
+
+	for i, input := range inputs {
+		var expr *ast
+		var gotResult any
+		var gotErr error
+
+		ctx := NewSimpleFuncStore()
+		ctx.SetVar("var1", int64(123))
+		ctx.SetVar("var2", "abc")
+		ImportMathFuncs(ctx)
+		parser := NewParser(ctx)
+
+		logTest(t, i+1, input.source, input.wantResult, input.wantErr)
+
+		r := strings.NewReader(input.source)
+		scanner := NewScanner(r, DefaultTranslations())
+
+		good := true
+		if expr, gotErr = parser.Parse(scanner); gotErr == nil {
+			gotResult, gotErr = expr.Eval(ctx)
+		}
+
+		if (gotResult == nil && input.wantResult != nil) || (gotResult != nil && input.wantResult == nil) {
+			t.Errorf("%d: %q -> result = %v [%T], want %v [%T]", i+1, input.source, gotResult, gotResult, input.wantResult, input.wantResult)
+			good = false
+		}
+
+		if gotList, okGot := gotResult.([]any); okGot {
+			if wantList, okWant := input.wantResult.([]any); okWant {
+				if (gotList == nil && wantList != nil) || (gotList != nil && wantList == nil) {
+					t.Errorf("%d: %q -> result = %v [%T], want %v [%T]", i+1, input.source, gotResult, gotResult, input.wantResult, input.wantResult)
+					good = false
+				} else {
+					equal := len(gotList) == len(wantList)
+					if equal {
+						for i, gotItem := range gotList {
+							wantItem := wantList[i]
+							equal = gotItem == wantItem
+							if !equal {
+								break
+							}
+						}
+					}
+					if !equal {
+						t.Errorf("%d: %q -> result = %v [%T], want %v [%T]", i+1, input.source, gotResult, gotResult, input.wantResult, input.wantResult)
+						good = false
+					}
+				}
+			}
+		}
+
+		if gotErr != input.wantErr {
+			if input.wantErr == nil || gotErr == nil || (gotErr.Error() != input.wantErr.Error()) {
+				t.Errorf("%d: %q  -> err = <%v>, want <%v>", i+1, input.source, gotErr, input.wantErr)
+				good = false
+			}
+		}
+
+		if good {
+			succeeded++
+		} else {
+			failed++
+		}
+	}
+	t.Log(fmt.Sprintf("test count: %d, succeeded count: %d, failed count: %d", len(inputs), succeeded, failed))
+}
+
+func logTest(t *testing.T, n int, source string, wantResult any, wantErr error) {
+	if wantErr == nil {
+		t.Log(fmt.Sprintf("[+]Test nr %3d -- %q  --> %v", n, source, wantResult))
+	} else {
+		t.Log(fmt.Sprintf("[-]Test nr %3d -- %q  --> %v", n, source, wantErr))
+	}
+}

plugins.go

@@ -1,131 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// plugin.go
-package expr
-
-import (
-	"fmt"
-	"io"
-	"os"
-	"plugin"
-	"strings"
-)
-
-var pluginRegister map[string]*plugin.Plugin
-
-func registerPlugin(name string, p *plugin.Plugin) (err error) {
-	if pluginExists(name) {
-		err = fmt.Errorf("plugin %q already loaded", name)
-	} else {
-		pluginRegister[name] = p
-	}
-	return
-}
-
-func pluginExists(name string) (exists bool) {
-	_, exists = pluginRegister[name]
-	return
-}
-
-func makePluginName(name string) (decorated string) {
-	var template string
-	if execName, err := os.Executable(); err != nil || !strings.Contains(execName, "debug") {
-		template = "expr-%s-plugin.so"
-	} else {
-		template = "expr-%s-plugin.so.debug"
-	}
-	decorated = fmt.Sprintf(template, name)
-	return
-}
-
-func importPlugin( /*ctx ExprContext,*/ dirList []string, name string) (err error) {
-	var filePath string
-	var p *plugin.Plugin
-	var sym plugin.Symbol
-	var moduleName string
-	var importFunc func(ExprContext)
-	var ok bool
-
-	decoratedName := makePluginName(name)
-
-	if filePath, err = makeFilepath(decoratedName, dirList); err != nil {
-		return
-	}
-
-	if p, err = plugin.Open(filePath); err != nil {
-		return
-	}
-
-	if sym, err = p.Lookup("MODULE_NAME"); err != nil {
-		return
-	}
-
-	if moduleName = *sym.(*string); moduleName == "" {
-		err = fmt.Errorf("plugin %q does not provide a valid module name", decoratedName)
-		return
-	}
-
-	if sym, err = p.Lookup("DEPENDENCIES"); err != nil {
-		return
-	}
-	if deps := *sym.(*[]string); len(deps) > 0 {
-		// var count int
-		if err = loadModules(dirList, deps); err != nil {
-			return
-		}
-	}
-
-	if sym, err = p.Lookup("ImportFuncs"); err != nil {
-		return
-	}
-
-	if importFunc, ok = sym.(func(ExprContext)); !ok {
-		err = fmt.Errorf("plugin %q does not provide a valid import function", decoratedName)
-		return
-	}
-
-	registerPlugin(moduleName, p)
-	importFunc(globalCtx)
-
-	return
-}
-
-func importPluginFromSearchPath(name any) (count int, err error) {
-	var moduleSpec any
-
-	dirList := buildSearchDirList("plugin", ENV_EXPR_PLUGIN_PATH)
-	count = 0
-	it := NewAnyIterator(name)
-	for moduleSpec, err = it.Next(); err == nil; moduleSpec, err = it.Next() {
-		if module, ok := moduleSpec.(string); ok {
-			if err = importPlugin(dirList, module); err != nil {
-				break
-			}
-			count++
-		} else {
-			err = fmt.Errorf("expected string as item nr %d, got %s", it.Index()+1, TypeName(moduleSpec))
-			break
-		}
-	}
-	if err == io.EOF {
-		err = nil
-	}
-	return
-}
-
-func loadModules(dirList []string, moduleNames []string) (err error) {
-	for _, name := range moduleNames {
-		if err1 := importPlugin(dirList, name); err1 != nil {
-			if !ImportInContext(name) {
-				err = err1
-				break
-			}
-		}
-	}
-	return
-}
-
-func init() {
-	pluginRegister = make(map[string]*plugin.Plugin)
-}

scanner.go

@@ -16,7 +16,6 @@ import (
 type scanner struct {
 	current      *Token
 	prev         *Token
-	stage        *Token
 	stream       *bufio.Reader
 	row          int
 	column       int
@@ -40,7 +39,7 @@ func DefaultTranslations() map[Symbol]Symbol {
 		SymKwAnd:           SymAnd,
 		SymDoubleVertBar:   SymOr,
 		SymKwOr:            SymOr,
-		// SymTilde:           SymNot,
+		SymTilde:           SymNot,
 		SymKwNot:           SymNot,
 		SymLessGreater:     SymNotEqual,
 	}
@@ -50,321 +49,234 @@ func DefaultTranslations() map[Symbol]Symbol {
 // 	return self.current
 // }
 
-func (scanner *scanner) readChar() (ch byte, err error) {
+func (self *scanner) readChar() (ch byte, err error) {
-	if ch, err = scanner.stream.ReadByte(); err == nil {
+	if ch, err = self.stream.ReadByte(); err == nil {
 		if ch == '\n' {
-			scanner.row++
+			self.row++
-			scanner.column = 0
+			self.column = 0
 		} else {
-			scanner.column++
+			self.column++
 		}
 	}
 	return
 }
 
-func (scanner *scanner) unreadChar() (err error) {
+func (self *scanner) unreadChar() (err error) {
-	if err = scanner.stream.UnreadByte(); err == nil {
+	if err = self.stream.UnreadByte(); err == nil {
-		if scanner.column--; scanner.column == 0 {
+		if self.column--; self.column == 0 {
-			if scanner.row--; scanner.row == 0 {
+			if self.row--; self.row == 0 {
 				err = errors.New("unread beyond the stream boundary")
 			} else {
-				scanner.column = 1
+				self.column = 1
 			}
 		}
 	}
 	return
 }
 
-func (scanner *scanner) UnreadToken() (err error) {
+func (self *scanner) Previous() *Token {
-	if scanner.stage == nil {
+	return self.prev
-		scanner.stage = scanner.current
-		scanner.current = scanner.prev
-	} else {
-		err = fmt.Errorf("staging already present, currently one level only of staging is allowed")
-	}
-	return
 }
 
-func (scanner *scanner) lastPos() (r, c int) {
+func (self *scanner) Next() (tk *Token) {
-	if scanner.prev != nil {
+	self.prev = self.current
-		r = scanner.prev.row
+	tk = self.current
-		c = scanner.prev.col
+	self.current = self.fetchNextToken()
-	}
-	return
-}
-
-func (scanner *scanner) Previous() *Token {
-	return scanner.prev
-}
-
-func (scanner *scanner) Next() (tk *Token) {
-	scanner.prev = scanner.current
-	tk = scanner.current
-	if scanner.stage != nil {
-		scanner.current = scanner.stage
-		scanner.stage = nil
-	} else {
-		scanner.current = scanner.fetchNextToken()
-	}
 	return tk
 }
 
-func (scanner *scanner) fetchNextToken() (tk *Token) {
+func (self *scanner) fetchNextToken() (tk *Token) {
-	var ch byte
+	if err := self.skipBlanks(); err != nil {
-	if err := scanner.skipBlanks(); err != nil {
+		return self.makeErrorToken(err)
-		return scanner.makeErrorToken(err)
 	}
 
 	escape := false
 	for {
-		ch, _ = scanner.readChar()
+		ch, _ := self.readChar()
 		switch ch {
 		case '+':
-			if next, _ := scanner.peek(); next == '+' {
+			if next, _ := self.peek(); next == '+' {
-				tk = scanner.moveOn(SymDoublePlus, ch, next)
+				tk = self.moveOn(SymDoublePlus, ch, next)
 			} else if next == '=' {
-				tk = scanner.moveOn(SymPlusEqual, ch, next)
+				tk = self.moveOn(SymPlusEqual, ch, next)
-			} else if next == '>' {
-				tk = scanner.moveOn(SymPlusGreater, ch, next)
 			} else {
-				tk = scanner.makeToken(SymPlus, ch)
+				tk = self.makeToken(SymPlus, ch)
 			}
 		case '-':
-			if next, _ := scanner.peek(); next == '-' {
+			if next, _ := self.peek(); next == '-' {
-				tk = scanner.moveOn(SymDoubleMinus, ch, next)
+				tk = self.moveOn(SymDoubleMinus, ch, next)
 			} else if next == '=' {
-				tk = scanner.moveOn(SymMinusEqual, ch, next)
+				tk = self.moveOn(SymMinusEqual, ch, next)
 			} else {
-				tk = scanner.makeToken(SymMinus, ch)
+				tk = self.makeToken(SymMinus, ch)
 			}
 		case '*':
-			if next, _ := scanner.peek(); next == '*' {
+			if next, _ := self.peek(); next == '*' {
-				tk = scanner.moveOn(SymDoubleStar, ch, next)
+				tk = self.moveOn(SymDoubleStar, ch, next)
 				// } else if next == '/' {
 				// 	tk = self.moveOn(SymClosedComment, ch, next)
-			} else if next, _ = scanner.peek(); next == '=' {
-				tk = scanner.moveOn(SymStarEqual, ch, next)
 			} else {
-				tk = scanner.makeToken(SymStar, ch)
+				tk = self.makeToken(SymStar, ch)
 			}
 		case '/':
-			if next, _ := scanner.peek(); next == '*' {
+			if next, _ := self.peek(); next == '*' {
-				scanner.readChar()
+				self.readChar()
-				tk = scanner.fetchBlockComment()
+				tk = self.fetchBlockComment()
-			} else if next, _ = scanner.peek(); next == '=' {
-				tk = scanner.moveOn(SymSlashEqual, ch, next)
 			} else if next == '/' {
-				scanner.readChar()
+				self.readChar()
-				tk = scanner.fetchOnLineComment()
+				tk = self.fetchOnLineComment()
 			} else {
-				tk = scanner.makeToken(SymSlash, ch)
+				tk = self.makeToken(SymSlash, ch)
 			}
 		case '\\':
 			if escape {
-				tk = scanner.makeToken(SymBackSlash, ch)
+				tk = self.makeToken(SymBackSlash, ch)
 				escape = false
 			} else {
 				escape = true
 			}
 		case '|':
-			if next, _ := scanner.peek(); next == '|' {
+			if next, _ := self.peek(); next == '|' {
-				tk = scanner.moveOn(SymDoubleVertBar, ch, next)
+				tk = self.moveOn(SymDoubleVertBar, ch, next)
-			} else if next, _ = scanner.peek(); next == '=' {
-				tk = scanner.moveOn(SymVertBarEqual, ch, next)
 			} else {
-				tk = scanner.makeToken(SymVertBar, ch)
+				tk = self.makeToken(SymVertBar, ch)
 			}
 		case ',':
-			tk = scanner.makeToken(SymComma, ch)
+			tk = self.makeToken(SymComma, ch)
-		case '^':
-			if next, _ := scanner.peek(); next == '=' {
-				tk = scanner.moveOn(SymCaretEqual, ch, next)
-			} else {
-				tk = scanner.makeToken(SymCaret, ch)
-			}
 		case ':':
-			if next, _ := scanner.peek(); next == ':' {
+			if next, _ := self.peek(); next == ':' {
-				tk = scanner.moveOn(SymDoubleColon, ch, next)
+				tk = self.moveOn(SymDoubleColon, ch, next)
 			} else {
-				tk = scanner.makeToken(SymColon, ch)
+				tk = self.makeToken(SymColon, ch)
 			}
 		case ';':
-			tk = scanner.makeToken(SymSemiColon, ch)
+			tk = self.makeToken(SymSemiColon, ch)
 		case '.':
 			//if next, _ := self.peek(); next >= '0' && next <= '9' {
 			//	tk = self.parseNumber(ch)
 			//} else if next == '/' {
-			if next, _ := scanner.peek(); next == '/' {
+			if next, _ := self.peek(); next == '/' {
-				tk = scanner.moveOn(SymDotSlash, ch, next)
+				tk = self.moveOn(SymDotSlash, ch, next)
-			} else if next == '.' {
-				if next1, _ := scanner.peek(); next1 == '.' {
-					tk = scanner.moveOn(SymTripleDot, ch, next, next1)
 			} else {
-					tk = scanner.moveOn(SymDoubleDot, ch, next)
+				tk = self.makeToken(SymDot, ch)
-				}
-			} else {
-				tk = scanner.makeToken(SymDot, ch)
 			}
 		case '\'':
-			if escape {
+			tk = self.makeToken(SymQuote, ch)
-				tk = scanner.makeToken(SymQuote, ch)
-				escape = false
-			} else {
-				tk = scanner.fetchString(ch)
-			}
 		case '"':
 			if escape {
-				tk = scanner.makeToken(SymDoubleQuote, ch)
+				tk = self.makeToken(SymDoubleQuote, ch)
 				escape = false
 			} else {
-				tk = scanner.fetchString(ch)
+				tk = self.fetchString()
 			}
 		case '`':
-			tk = scanner.makeToken(SymBackTick, ch)
+			tk = self.makeToken(SymBackTick, ch)
 		case '!':
-			if next, _ := scanner.peek(); next == '=' {
+			if next, _ := self.peek(); next == '=' {
-				tk = scanner.moveOn(SymNotEqual, ch, next)
+				tk = self.moveOn(SymNotEqual, ch, next)
 			} else {
-				tk = scanner.makeToken(SymExclamation, ch)
+				tk = self.makeToken(SymExclamation, ch)
 			}
 		case '?':
-			if next, _ := scanner.peek(); next == '?' {
+			if next, _ := self.peek(); next == '?' {
-				tk = scanner.moveOn(SymDoubleQuestion, ch, next)
+				tk = self.moveOn(SymDoubleQuestion, ch, next)
-			} else if next == '=' {
+			} else if next, _ := self.peek(); next == '=' {
-				tk = scanner.moveOn(SymQuestionEqual, ch, next)
+				tk = self.moveOn(SymQuestionEqual, ch, next)
-			} else if next == '!' {
-				tk = scanner.moveOn(SymQuestionExclam, ch, next)
 			} else {
-				tk = scanner.makeToken(SymQuestion, ch)
+				tk = self.makeToken(SymQuestion, ch)
 			}
 		case '&':
-			if next, _ := scanner.peek(); next == '&' {
+			if next, _ := self.peek(); next == '&' {
-				tk = scanner.moveOn(SymDoubleAmpersand, ch, next)
+				tk = self.moveOn(SymDoubleAmpersand, ch, next)
-			} else if next, _ = scanner.peek(); next == '=' {
-				tk = scanner.moveOn(SymAmpersandEqual, ch, next)
 			} else {
-				tk = scanner.makeToken(SymAmpersand, ch)
+				tk = self.makeToken(SymAmpersand, ch)
 			}
 		case '%':
-			if next, _ := scanner.peek(); next == '=' {
+			tk = self.makeToken(SymPercent, ch)
-				tk = scanner.moveOn(SymPercEqual, ch, next)
-			} else {
-				tk = scanner.makeToken(SymPercent, ch)
-			}
 		case '#':
-			tk = scanner.makeToken(SymHash, ch)
+			tk = self.makeToken(SymHash, ch)
 		case '@':
-			if next, _ := scanner.peek(); (next >= 'a' && next <= 'z') || (next >= 'A' && next <= 'Z') {
+			if next, _ := self.peek(); (next >= 'a' && next <= 'z') || (next >= 'A' && next <= 'Z') {
-				scanner.readChar()
+				self.readChar()
-				if tk = scanner.fetchIdentifier(next); tk.Sym == SymIdentifier {
+				if tk = self.fetchIdentifier(next); tk.Sym == SymIdentifier {
 					//tk.Sym = SymIdRef
 					tk.source = "@" + tk.source
 				} else {
-					tk = scanner.makeErrorToken(fmt.Errorf("invalid variable reference %q", tk.source))
+					tk = self.makeErrorToken(fmt.Errorf("invalid variable reference %q", tk.source))
 				}
 			} else if next == '@' {
-				tk = scanner.moveOn(SymDoubleAt, ch, next)
+				tk = self.moveOn(SymDoubleAt, ch, next)
 			} else {
-				tk = scanner.makeToken(SymAt, ch)
+				tk = self.makeToken(SymAt, ch)
 			}
 		case '_':
-			tk = scanner.makeToken(SymUndescore, ch)
+			tk = self.makeToken(SymUndescore, ch)
 		case '=':
-			if next, _ := scanner.peek(); next == '=' {
+			if next, _ := self.peek(); next == '=' {
-				tk = scanner.moveOn(SymDoubleEqual, ch, next)
+				tk = self.moveOn(SymDoubleEqual, ch, next)
 			} else {
-				tk = scanner.makeToken(SymEqual, ch)
+				tk = self.makeToken(SymEqual, ch)
 			}
 		case '<':
-			if next, _ := scanner.peek(); next == '=' {
+			if next, _ := self.peek(); next == '=' {
-				tk = scanner.moveOn(SymLessOrEqual, ch, next)
+				tk = self.moveOn(SymLessOrEqual, ch, next)
 			} else if next == '<' {
-				scanner.readChar()
+				tk = self.moveOn(SymAppend, ch, next)
-				next2, _ := scanner.readChar()
-				scanner.unreadChar()
-				if next2 == '=' {
-					tk = scanner.moveOn(SymDoubleLessEqual, ch, next, next2)
-				} else {
-					tk = scanner.accept(SymDoubleLess, ch, next)
-				}
 			} else if next == '>' {
-				tk = scanner.moveOn(SymLessGreater, ch, next)
+				tk = self.moveOn(SymLessGreater, ch, next)
-			} else if next == '+' {
-				tk = scanner.moveOn(SymLessPlus, ch, next)
 			} else {
-				tk = scanner.makeToken(SymLess, ch)
+				tk = self.makeToken(SymLess, ch)
 			}
 		case '>':
-			if next, _ := scanner.peek(); next == '=' {
+			if next, _ := self.peek(); next == '=' {
-				tk = scanner.moveOn(SymGreaterOrEqual, ch, next)
+				tk = self.moveOn(SymGreaterOrEqual, ch, next)
 			} else if next == '>' {
-				scanner.readChar()
+				tk = self.moveOn(SymInsert, ch, next)
-				next2, _ := scanner.readChar()
-				scanner.unreadChar()
-				if next2 == '=' {
-					tk = scanner.moveOn(SymDoubleGreaterEqual, ch, next, next2)
 			} else {
-					tk = scanner.accept(SymDoubleGreater, ch, next)
+				tk = self.makeToken(SymGreater, ch)
-				}
-			} else {
-				tk = scanner.makeToken(SymGreater, ch)
 			}
 		case '$':
-			if next, _ := scanner.peek(); next == '(' {
+			tk = self.makeToken(SymDollar, ch)
-				tk = scanner.moveOn(SymDollarRound, ch, next)
-				tk.source += ")"
-			} else if next == '$' {
-				tk = scanner.moveOn(SymDoubleDollar, ch, next)
-			} else {
-				tk = scanner.makeToken(SymDollar, ch)
-			}
 		case '(':
-			//			if next, _ := scanner.peek(); next == ')' {
+			tk = self.makeToken(SymOpenRound, ch)
-			//				tk = scanner.moveOn(SymOpenClosedRound, ch, next)
-			//			} else {
-			tk = scanner.makeToken(SymOpenRound, ch)
-			//			}
 		case ')':
-			tk = scanner.makeToken(SymClosedRound, ch)
+			tk = self.makeToken(SymClosedRound, ch)
 		case '[':
-			tk = scanner.makeToken(SymOpenSquare, ch)
+			tk = self.makeToken(SymOpenSquare, ch)
 		case ']':
-			tk = scanner.makeToken(SymClosedSquare, ch)
+			tk = self.makeToken(SymClosedSquare, ch)
 		case '{':
-			tk = scanner.makeToken(SymOpenBrace, ch)
+			tk = self.makeToken(SymOpenBrace, ch)
 		case '}':
-			tk = scanner.makeToken(SymClosedBrace, ch)
+			tk = self.makeToken(SymClosedBrace, ch)
 		case '~':
-			tk = scanner.makeToken(SymTilde, ch)
+			tk = self.makeToken(SymTilde, ch)
 		case 0:
 			if escape {
-				tk = scanner.makeErrorToken(errors.New("incomplete escape sequence"))
+				tk = self.makeErrorToken(errors.New("incomplete escape sequence"))
 			}
 			escape = false
 		default:
 			if /*ch == '_' ||*/ (ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z') {
-				if tk = scanner.fetchIdentifier(ch); tk.Sym == SymKwFunc {
+				if tk = self.fetchIdentifier(ch); tk.Sym == SymKwFunc {
-					if next, _ := scanner.peek(); next == '(' {
+					if next, _ := self.peek(); next == '(' {
-						tk = scanner.moveOn(SymFuncDef, ch, next)
+						tk = self.moveOn(SymFuncDef, ch, next)
 					}
 				}
 			} else if ch >= '0' && ch <= '9' {
-				tk = scanner.parseNumber(ch)
+				tk = self.parseNumber(ch)
 			}
 		}
 		if !escape {
 			break
 		}
 	}
-	if tk == nil {
-		tk = NewErrorToken(scanner.row, scanner.column, fmt.Errorf("unknown symbol '%c'", ch))
-	}
 	return
 }
 
-func (scanner *scanner) sync(err error) error {
+func (self *scanner) sync(err error) error {
 	if err == nil {
-		err = scanner.unreadChar()
+		err = self.unreadChar()
 	}
 	return err
 }
@@ -385,32 +297,32 @@ func isHexDigit(ch byte) bool {
 	return (ch >= '0' && ch <= '9') || (ch >= 'a' && ch <= 'f') || (ch >= 'A' && ch <= 'F')
 }
 
-func (scanner *scanner) initBase(currentFirstCh byte) (firstCh byte, numBase int, digitFunc func(byte) bool, err error) {
+func (self *scanner) initBase(sb *strings.Builder, currentFirstCh byte) (firstCh byte, numBase int, digitFunc func(byte) bool, err error) {
 	var ch byte
 	var digitType string
 	firstCh = currentFirstCh
 	digitFunc = isDecimalDigit
 	numBase = 10
 
-	if ch, err = scanner.peek(); err == nil {
+	if ch, err = self.peek(); err == nil {
 		if ch == 'b' || ch == 'B' {
 			numBase = 2
 			digitType = "binary"
-			scanner.readChar()
+			self.readChar()
 			digitFunc = isBinaryDigit
-			firstCh, err = scanner.readChar()
+			firstCh, err = self.readChar()
 		} else if ch == 'o' || ch == 'O' {
 			numBase = 8
 			digitType = "octal"
-			scanner.readChar()
+			self.readChar()
 			digitFunc = isOctalDigit
-			firstCh, err = scanner.readChar()
+			firstCh, err = self.readChar()
 		} else if ch == 'x' || ch == 'X' {
 			numBase = 16
 			digitType = "hex"
-			scanner.readChar()
+			self.readChar()
 			digitFunc = isHexDigit
-			firstCh, err = scanner.readChar()
+			firstCh, err = self.readChar()
 		}
 		if err == nil && !digitFunc(firstCh) {
 			if len(digitType) == 0 {
@@ -424,7 +336,7 @@ func (scanner *scanner) initBase(currentFirstCh byte) (firstCh byte, numBase int
 	return
 }
 
-func (scanner *scanner) parseNumber(firstCh byte) (tk *Token) {
+func (self *scanner) parseNumber(firstCh byte) (tk *Token) {
 	var err error
 	var ch byte
 	var sym Symbol = SymInteger
@@ -433,9 +345,9 @@ func (scanner *scanner) parseNumber(firstCh byte) (tk *Token) {
 	var numBase = 10
 
 	if firstCh == '0' {
-		firstCh, numBase, isDigit, err = scanner.initBase(firstCh)
+		firstCh, numBase, isDigit, err = self.initBase(&sb, firstCh)
 	}
-	for ch = firstCh; err == nil && isDigit(ch); ch, err = scanner.readChar() {
+	for ch = firstCh; err == nil && isDigit(ch); ch, err = self.readChar() {
 		sb.WriteByte(ch)
 	}
 
@@ -443,96 +355,77 @@ func (scanner *scanner) parseNumber(firstCh byte) (tk *Token) {
 		if err == nil && ch == '.' {
 			sym = SymFloat
 			sb.WriteByte(ch)
-			ch, err = scanner.readChar()
+			ch, err = self.readChar()
 			if ch >= '0' && ch <= '9' {
-				for ; err == nil && (ch >= '0' && ch <= '9'); ch, err = scanner.readChar() {
+				for ; err == nil && (ch >= '0' && ch <= '9'); ch, err = self.readChar() {
 					sb.WriteByte(ch)
 				}
 			}
 		}
-		if err == nil {
+		if err == nil && (ch == 'e' || ch == 'E') {
-			if ch == 'e' || ch == 'E' {
 			sym = SymFloat
 			sb.WriteByte(ch)
-				if ch, err = scanner.readChar(); err == nil {
+			if ch, err = self.readChar(); err == nil {
 				if ch == '+' || ch == '-' {
 					sb.WriteByte(ch)
-						ch, err = scanner.readChar()
+					ch, err = self.readChar()
 				}
 				if ch >= '0' && ch <= '9' {
-						for ; err == nil && (ch >= '0' && ch <= '9'); ch, err = scanner.readChar() {
+					for ; err == nil && (ch >= '0' && ch <= '9'); ch, err = self.readChar() {
 						sb.WriteByte(ch)
 					}
 				} else {
-						err = fmt.Errorf("[%d:%d] expected integer exponent, got %c", scanner.row, scanner.column, ch)
+					err = errors.New("expected integer exponent")
-					}
-				}
-			} else if ch == '(' {
-				sym = SymFraction
-				sb.WriteByte(ch)
-				ch, err = scanner.readChar()
-				for ; err == nil && (ch >= '0' && ch <= '9'); ch, err = scanner.readChar() {
-					sb.WriteByte(ch)
-				}
-				if err == nil {
-					if ch != ')' {
-						err = fmt.Errorf("[%d:%d] expected ')', got '%c'", scanner.row, scanner.column, ch)
-					} else {
-						sb.WriteByte(ch)
-						_, err = scanner.readChar()
-					}
 				}
 			}
 		}
 	}
 
 	if err != nil && err != io.EOF {
-		tk = scanner.makeErrorToken(err)
+		tk = self.makeErrorToken(err)
 	} else {
 		var value any
-		_ = scanner.sync(err) // TODO: Check this function
+		err = self.sync(err)
 		txt := sb.String()
 		if sym == SymFloat {
 			value, err = strconv.ParseFloat(txt, 64)
-		} else if sym == SymFraction {
-			value, err = makeGeneratingFraction(txt)
 		} else {
 			value, err = strconv.ParseInt(txt, numBase, 64)
 		}
 		if err == nil {
-			tk = scanner.makeValueToken(sym, txt, value)
+			tk = self.makeValueToken(sym, txt, value)
 		} else {
-			tk = scanner.makeErrorToken(err)
+			tk = self.makeErrorToken(err)
 		}
 	}
 	return
 }
 
-func (scanner *scanner) fetchIdentifier(firstCh byte) (tk *Token) {
+func (self *scanner) fetchIdentifier(firstCh byte) (tk *Token) {
 	var err error
 	var sb strings.Builder
-	for ch := firstCh; err == nil && (ch == '_' || (ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z') || (ch >= '0' && ch <= '9')); ch, err = scanner.readChar() {
+	for ch := firstCh; err == nil && (ch == '_' || (ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z') || (ch >= '0' && ch <= '9')); ch, err = self.readChar() {
 		sb.WriteByte(ch)
 	}
 
 	if err != nil && err != io.EOF {
-		tk = scanner.makeErrorToken(err)
+		tk = self.makeErrorToken(err)
-	} else if err = scanner.sync(err); err != nil && err != io.EOF {
+	} else if err = self.sync(err); err != nil && err != io.EOF {
-		tk = scanner.makeErrorToken(err)
+		tk = self.makeErrorToken(err)
 	} else {
 		txt := sb.String()
 		uptxt := strings.ToUpper(txt)
 		if sym, ok := keywords[uptxt]; ok {
-			tk = scanner.makeKeywordToken(sym, uptxt)
+			tk = self.makeKeywordToken(sym, uptxt)
 		} else if uptxt == `TRUE` {
-			tk = scanner.makeValueToken(SymBool, txt, true)
+			tk = self.makeValueToken(SymBool, txt, true)
 		} else if uptxt == `FALSE` {
-			tk = scanner.makeValueToken(SymBool, txt, false)
+			tk = self.makeValueToken(SymBool, txt, false)
-		} else if ch, _ := scanner.peek(); ch == '(' {
+		} else if ch, _ := self.peek(); ch == '(' {
-			scanner.readChar()
+			self.readChar()
-			tk = scanner.makeValueToken(SymFuncCall, txt+"(", txt)
+			tk = self.makeValueToken(SymFuncCall, txt+"(", txt)
 		} else {
-			tk = scanner.makeValueToken(SymIdentifier, txt, txt)
+			tk = self.makeValueToken(SymIdentifier, txt, txt)
 		}
 	}
 
@@ -552,29 +445,29 @@ func (scanner *scanner) fetchIdentifier(firstCh byte) (tk *Token) {
 	return
 }
 
-func (scanner *scanner) fetchBlockComment() *Token {
+func (self *scanner) fetchBlockComment() *Token {
-	return scanner.fetchUntil(SymComment, false, '*', '/')
+	return self.fetchUntil(SymComment, false, '*', '/')
 }
 
-func (scanner *scanner) fetchOnLineComment() *Token {
+func (self *scanner) fetchOnLineComment() *Token {
-	return scanner.fetchUntil(SymComment, true, '\n')
+	return self.fetchUntil(SymComment, true, '\n')
 }
 
-func (scanner *scanner) fetchUntil(sym Symbol, allowEos bool, endings ...byte) (tk *Token) {
+func (self *scanner) fetchUntil(sym Symbol, allowEos bool, endings ...byte) (tk *Token) {
 	var err error
 	var ch byte
 	var sb strings.Builder
 	var value string
 	ring := NewByteSlider(len(endings))
 	endReached := false
-	for ch, err = scanner.readChar(); err == nil && !endReached; {
+	for ch, err = self.readChar(); err == nil && !endReached; {
 		sb.WriteByte(ch)
 		ring.PushEnd(ch)
 		if ring.Equal(endings) {
 			value = sb.String()[0 : sb.Len()-len(endings)]
 			endReached = true
 		} else {
-			ch, err = scanner.readChar()
+			ch, err = self.readChar()
 		}
 	}
 	if !endReached && allowEos {
@@ -583,18 +476,18 @@ func (scanner *scanner) fetchUntil(sym Symbol, allowEos bool, endings ...byte) (
 	}
 
 	if endReached {
-		tk = scanner.makeValueToken(sym, "", value)
+		tk = self.makeValueToken(sym, "", value)
 	} else {
-		tk = scanner.makeErrorToken(err)
+		tk = self.makeErrorToken(err)
 	}
 	return
 }
 
-func (scanner *scanner) fetchString(termCh byte) (tk *Token) {
+func (self *scanner) fetchString() (tk *Token) {
 	var err error
 	var ch, prev byte
 	var sb strings.Builder
-	for ch, err = scanner.readChar(); err == nil; ch, err = scanner.readChar() {
+	for ch, err = self.readChar(); err == nil; ch, err = self.readChar() {
 		if prev == '\\' {
 			switch ch {
 			case '"':
@@ -611,7 +504,7 @@ func (scanner *scanner) fetchString(termCh byte) (tk *Token) {
 				sb.WriteByte(ch)
 			}
 			prev = 0
-		} else if ch == termCh {
+		} else if ch == '"' {
 			break
 		} else {
 			prev = ch
@@ -622,72 +515,65 @@ func (scanner *scanner) fetchString(termCh byte) (tk *Token) {
 	}
 	if err != nil {
 		if err == io.EOF {
-			tk = scanner.makeErrorToken(errors.New(string(termCh)))
+			tk = self.makeErrorToken(errors.New("missing string termination \""))
 		} else {
-			tk = scanner.makeErrorToken(err)
+			tk = self.makeErrorToken(err)
 		}
 	} else {
 		txt := sb.String()
-		tk = scanner.makeValueToken(SymString, `"`+txt+`"`, txt)
+		tk = self.makeValueToken(SymString, `"`+txt+`"`, txt)
 	}
 	return
 }
 
-func (scanner *scanner) peek() (next byte, err error) {
+func (self *scanner) peek() (next byte, err error) {
 	var one []byte
-	if one, err = scanner.stream.Peek(1); err == nil {
+	if one, err = self.stream.Peek(1); err == nil {
 		next = one[0]
 	}
 	return
 }
 
-func (scanner *scanner) skipBlanks() (err error) {
+func (self *scanner) skipBlanks() (err error) {
 	var one []byte
-	for one, err = scanner.stream.Peek(1); err == nil && one[0] <= 32; one, err = scanner.stream.Peek(1) {
+	for one, err = self.stream.Peek(1); err == nil && one[0] <= 32; one, err = self.stream.Peek(1) {
-		scanner.readChar()
+		self.readChar()
 	}
 	return
 }
 
-func (scanner *scanner) translate(sym Symbol) Symbol {
+func (self *scanner) translate(sym Symbol) Symbol {
-	if scanner.translations != nil {
+	if self.translations != nil {
-		if translatedSym, ok := scanner.translations[sym]; ok {
+		if translatedSym, ok := self.translations[sym]; ok {
 			return translatedSym
 		}
 	}
 	return sym
 }
 
-func (scanner *scanner) moveOn(sym Symbol, chars ...byte) (tk *Token) {
+func (self *scanner) moveOn(sym Symbol, chars ...byte) (tk *Token) {
-	tk = NewToken(scanner.row, scanner.column, scanner.translate(sym), string(chars))
+	tk = NewToken(self.row, self.column, self.translate(sym), string(chars))
-	// for i := 1; i < len(chars); i++ {
+	for i := 1; i < len(chars); i++ {
-	if len(chars) > 1 {
+		self.readChar()
-		scanner.readChar()
 	}
-	// }
 	return
 }
 
-func (scanner *scanner) accept(sym Symbol, chars ...byte) (tk *Token) {
+func (self *scanner) makeToken(sym Symbol, chars ...byte) (tk *Token) {
-	tk = NewToken(scanner.row, scanner.column, scanner.translate(sym), string(chars))
+	tk = NewToken(self.row, self.column, self.translate(sym), string(chars))
 	return
 }
 
-func (scanner *scanner) makeToken(sym Symbol, chars ...byte) (tk *Token) {
+func (self *scanner) makeKeywordToken(sym Symbol, upperCaseKeyword string) (tk *Token) {
-	tk = NewToken(scanner.row, scanner.column, scanner.translate(sym), string(chars))
+	tk = NewToken(self.row, self.column, self.translate(sym), upperCaseKeyword)
 	return
 }
 
-func (scanner *scanner) makeKeywordToken(sym Symbol, upperCaseKeyword string) (tk *Token) {
+func (self *scanner) makeValueToken(sym Symbol, source string, value any) (tk *Token) {
-	tk = NewToken(scanner.row, scanner.column, scanner.translate(sym), upperCaseKeyword)
+	tk = NewValueToken(self.row, self.column, self.translate(sym), source, value)
 	return
 }
 
-func (scanner *scanner) makeValueToken(sym Symbol, source string, value any) (tk *Token) {
+func (self *scanner) makeErrorToken(err error) *Token {
-	tk = NewValueToken(scanner.row, scanner.column, scanner.translate(sym), source, value)
+	return NewErrorToken(self.row, self.column, err)
-	return
-}
-
-func (scanner *scanner) makeErrorToken(err error) *Token {
-	return NewErrorToken(scanner.row, scanner.column, err)
 }

scanner_test.go

@@ -1,12 +1,12 @@
 // Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
 // All rights reserved.
 
-// t_scanner_test.go
+// scanner_test.go
 package expr
 
 import (
 	"errors"
-	"reflect"
+	"fmt"
 	"strings"
 	"testing"
 )
@@ -36,7 +36,7 @@ func TestScanner(t *testing.T) {
 		/* 14 */ {`:`, SymColon, nil, nil},
 		/* 15 */ {`;`, SymSemiColon, nil, nil},
 		/* 16 */ {`.`, SymDot, nil, nil},
-		/* 17 */ {`0.5`, SymFloat, float64(0.5), nil},
+		/* 17 */ {`.5`, SymFloat, float64(0.5), nil},
 		/* 18 */ {`\\`, SymBackSlash, nil, nil},
 		/* 19 */ {"`", SymBackTick, nil, nil},
 		/* 20 */ {"?", SymQuestion, nil, nil},
@@ -44,7 +44,7 @@ func TestScanner(t *testing.T) {
 		/* 22 */ {"@", SymAt, nil, nil},
 		/* 23 */ {`#`, SymHash, nil, nil},
 		/* 24 */ {`%`, SymPercent, nil, nil},
-		/* 25 */ {`\'`, SymQuote, nil, nil},
+		/* 25 */ {`'`, SymQuote, nil, nil},
 		/* 26 */ {`\"`, SymDoubleQuote, nil, nil},
 		/* 27 */ {`_`, SymUndescore, nil, nil},
 		/* 28 */ {`<>`, SymLessGreater, nil, nil},
@@ -55,31 +55,27 @@ func TestScanner(t *testing.T) {
 		/* 33 */ {`(`, SymOpenRound, nil, nil},
 		/* 34 */ {`)`, SymClosedRound, nil, nil},
 		/* 35 */ {`1E+2`, SymFloat, float64(100), nil},
-		/* 36 */ {`1E+x`, SymError, errors.New("[1:5] expected integer exponent, got x"), nil},
+		/* 36 */ {`1E+x`, SymError, errors.New("expected integer exponent"), nil},
 		/* 37 */ {`$`, SymDollar, nil, nil},
 		/* 38 */ {`\`, SymError, errors.New("incomplete escape sequence"), nil},
 		/* 39 */ {`"string"`, SymString, "string", nil},
-		/* 40 */ {`identifier`, SymIdentifier, "identifier", nil},
+		/* 39 */ {`identifier`, SymIdentifier, "identifier", nil},
-		/* 41 */ {`1.2(3)`, SymFraction, newFraction(37, 30), nil},
 	}
 
 	for i, input := range inputs {
-		// if i != 40 {
+
-		// 	continue
-		// }
 		if input.wantErr == nil {
-			t.Logf("[+]Test nr %2d -- %q", i+1, input.source)
+			t.Log(fmt.Sprintf("[+]Test nr %2d -- %q", i+1, input.source))
 		} else {
-			t.Logf("[-]Test nr %2d -- %q", i+1, input.source)
+			t.Log(fmt.Sprintf("[-]Test nr %2d -- %q", i+1, input.source))
 		}
 
 		r := strings.NewReader(input.source)
 		scanner := NewScanner(r, nil)
 
 		if tk := scanner.Next(); tk == nil {
-			t.Errorf("%d: %q -> got = (nil), want %v (value %v [%T])", i+1, input.source, input.wantSym, input.wantValue, input.wantValue)
+			t.Errorf("%d: %q -> got = (nil), want %v (value %v [%T)", i+1, input.source, input.wantSym, input.wantValue, input.wantValue)
-			// } else if tk.Sym != input.wantSym || tk.Value != input.wantValue {
+		} else if tk.Sym != input.wantSym || tk.Value != input.wantValue {
-		} else if tk.Sym != input.wantSym || !reflect.DeepEqual(tk.Value, input.wantValue) {
 			if tk.Sym == SymError && input.wantSym == tk.Sym {
 				if tkErr, tkOk := tk.Value.(error); tkOk {
 					if inputErr, inputOk := input.wantValue.(error); inputOk {
@@ -90,7 +86,7 @@ func TestScanner(t *testing.T) {
 					}
 				}
 			} else {
-				t.Errorf("%d: %q -> got = %v (value=%v [%T]), want %v (value=%v [%T])", i+1,
+				t.Errorf("%d: %q -> got = %v (value=%v [%T), want %v (value=%v [%T)", i+1,
 					input.source, tk.Sym, tk.Value, tk.Value, input.wantSym, input.wantValue, input.wantValue)
 			}
 		}

simple-func-store.go

@@ -0,0 +1,82 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
+// simple-func-store.go
+package expr
+
+import "fmt"
+
+type SimpleFuncStore struct {
+	SimpleVarStore
+	funcStore map[string]*funcInfo
+}
+
+type funcInfo struct {
+	name    string
+	minArgs int
+	maxArgs int
+	functor Functor
+}
+
+func (info *funcInfo) Name() string {
+	return info.name
+}
+
+func (info *funcInfo) MinArgs() int {
+	return info.minArgs
+}
+
+func (info *funcInfo) MaxArgs() int {
+	return info.maxArgs
+}
+
+func (info *funcInfo) Functor() Functor {
+	return info.functor
+}
+
+func NewSimpleFuncStore() *SimpleFuncStore {
+	return &SimpleFuncStore{
+		SimpleVarStore: SimpleVarStore{varStore: make(map[string]any)},
+		funcStore:      make(map[string]*funcInfo),
+	}
+}
+
+func (ctx *SimpleFuncStore) Clone() ExprContext {
+	return &SimpleFuncStore{
+		SimpleVarStore: SimpleVarStore{varStore: CloneMap(ctx.varStore)},
+		funcStore:      CloneMap(ctx.funcStore),
+	}
+}
+
+func (ctx *SimpleFuncStore) GetFuncInfo(name string) (info ExprFunc) {
+	info, _ = ctx.funcStore[name]
+	return
+}
+
+func (ctx *SimpleFuncStore) RegisterFunc(name string, functor Functor, minArgs, maxArgs int) {
+	ctx.funcStore[name] = &funcInfo{name: name, minArgs: minArgs, maxArgs: maxArgs, functor: functor}
+}
+
+func (ctx *SimpleFuncStore) EnumFuncs(acceptor func(name string) (accept bool)) (funcNames []string) {
+	funcNames = make([]string, 0)
+	for name := range ctx.funcStore {
+		if acceptor != nil {
+			if acceptor(name) {
+				funcNames = append(funcNames, name)
+			}
+		} else {
+			funcNames = append(funcNames, name)
+		}
+	}
+	return
+}
+
+func (ctx *SimpleFuncStore) Call(name string, args []any) (result any, err error) {
+	if info, exists := ctx.funcStore[name]; exists {
+		functor := info.functor
+		result, err = functor.Invoke(ctx, name, args)
+	} else {
+		err = fmt.Errorf("unknown function %s()", name)
+	}
+	return
+}

simple-store.go

@@ -1,191 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// simple-store.go
-package expr
-
-import (
-	"fmt"
-	"slices"
-	// "strings"
-)
-
-type SimpleStore struct {
-	parent    ExprContext
-	varStore  map[string]any
-	funcStore map[string]ExprFunc
-}
-
-func NewSimpleStore() *SimpleStore {
-	ctx := &SimpleStore{
-		varStore:  make(map[string]any),
-		funcStore: make(map[string]ExprFunc),
-	}
-	return ctx
-}
-
-func filterRefName(name string) bool  { return name[0] != '@' }
-//func filterPrivName(name string) bool { return name[0] != '_' }
-
-func (ctx *SimpleStore) SetParent(parentCtx ExprContext) {
-	ctx.parent = parentCtx
-}
-
-func (ctx *SimpleStore) GetParent() ExprContext {
-	return ctx.parent
-}
-
-func (ctx *SimpleStore) Clone() ExprContext {
-	clone := &SimpleStore{
-		varStore:  CloneFilteredMap(ctx.varStore, filterRefName),
-		funcStore: CloneFilteredMap(ctx.funcStore, filterRefName),
-	}
-	return clone
-}
-
-// func (ctx *SimpleStore) Merge(src ExprContext) {
-// 	for _, name := range src.EnumVars(filterRefName) {
-// 		ctx.varStore[name], _ = src.GetVar(name)
-// 	}
-// 	for _, name := range src.EnumFuncs(filterRefName) {
-// 		ctx.funcStore[name], _ = src.GetFuncInfo(name)
-// 	}
-// }
-
-func (ctx *SimpleStore) ToString(opt FmtOpt) string {
-	dict := ctx.ToDict()
-	return dict.ToString(opt)
-}
-
-func (ctx *SimpleStore) varsToDict(dict *DictType) *DictType {
-	names := ctx.EnumVars(nil)
-	slices.Sort(names)
-	for _, name := range ctx.EnumVars(nil) {
-		value, _ := ctx.GetVar(name)
-		if f, ok := value.(Formatter); ok {
-			(*dict)[name] = f.ToString(0)
-		} else if _, ok = value.(Functor); ok {
-			(*dict)[name] = "func(){}"
-		} else {
-			(*dict)[name] = fmt.Sprintf("%v", value)
-		}
-	}
-	return dict
-}
-
-func (ctx *SimpleStore) funcsToDict(dict *DictType) *DictType {
-	names := ctx.EnumFuncs(func(name string) bool { return true })
-	slices.Sort(names)
-	for _, name := range names {
-		value, _ := ctx.GetFuncInfo(name)
-		if formatter, ok := value.(Formatter); ok {
-			(*dict)[name] = formatter.ToString(0)
-		} else {
-			(*dict)[name] = fmt.Sprintf("%v", value)
-		}
-	}
-	return dict
-}
-
-func (ctx *SimpleStore) ToDict() (dict *DictType) {
-	dict = MakeDict()
-	(*dict)["variables"] = ctx.varsToDict(MakeDict())
-	(*dict)["functions"] = ctx.funcsToDict(MakeDict())
-	return
-}
-
-func (ctx *SimpleStore) GetVar(varName string) (v any, exists bool) {
-	v, exists = ctx.varStore[varName]
-	return
-}
-
-func (ctx *SimpleStore) GetLast() (v any) {
-	v = ctx.varStore["last"]
-	return
-}
-
-func (ctx *SimpleStore) UnsafeSetVar(varName string, value any) {
-	// fmt.Printf("[%p] setVar(%v, %v)\n", ctx, varName, value)
-	ctx.varStore[varName] = value
-}
-
-func (ctx *SimpleStore) SetVar(varName string, value any) {
-	// fmt.Printf("[%p] SetVar(%v, %v)\n", ctx, varName, value)
-	if allowedValue, ok := fromGenericAny(value); ok {
-		ctx.varStore[varName] = allowedValue
-	} else {
-		panic(fmt.Errorf("unsupported type %T of value %v", value, value))
-	}
-}
-
-func (ctx *SimpleStore) EnumVars(acceptor func(name string) (accept bool)) (varNames []string) {
-	varNames = make([]string, 0)
-	for name := range ctx.varStore {
-		if acceptor != nil {
-			if acceptor(name) {
-				varNames = append(varNames, name)
-			}
-		} else {
-			varNames = append(varNames, name)
-		}
-	}
-	return
-}
-
-func (ctx *SimpleStore) VarCount() int {
-	return len(ctx.varStore)
-}
-
-func (ctx *SimpleStore) DeleteVar(varName string) {
-	delete(ctx.varStore, varName)
-}
-
-func (ctx *SimpleStore) GetFuncInfo(name string) (info ExprFunc, exists bool) {
-	info, exists = ctx.funcStore[name]
-	return
-}
-
-func (ctx *SimpleStore) RegisterFuncInfo(info ExprFunc) {
-	ctx.funcStore[info.Name()], _ = info.(*funcInfo)
-}
-
-func (ctx *SimpleStore) RegisterFunc(name string, functor Functor, returnType string, params []ExprFuncParam)  (exprFunc ExprFunc, err error) {
-	var info *funcInfo
-	if info, err = newFuncInfo(name, functor, returnType, params); err == nil {
-		ctx.funcStore[name] = info
-		exprFunc = info
-	}
-	return
-}
-
-func (ctx *SimpleStore) EnumFuncs(acceptor func(name string) (accept bool)) (funcNames []string) {
-	funcNames = make([]string, 0)
-	for name := range ctx.funcStore {
-		if acceptor != nil {
-			if acceptor(name) {
-				funcNames = append(funcNames, name)
-			}
-		} else {
-			funcNames = append(funcNames, name)
-		}
-	}
-	return
-}
-
-func (ctx *SimpleStore) FuncCount() int {
-	return len(ctx.funcStore)
-}
-
-func (ctx *SimpleStore) DeleteFunc(funcName string) {
-	delete(ctx.funcStore, funcName)
-}
-
-func (ctx *SimpleStore) Call(name string, args map[string]any) (result any, err error) {
-	if info, exists := GetLocalFuncInfo(ctx, name); exists {
-		functor := info.Functor()
-		result, err = functor.InvokeNamed(ctx, name, args)
-	} else {
-		err = fmt.Errorf("unknown function %s()", name)
-	}
-	return
-}

simple-var-store.go

@@ -0,0 +1,70 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
+// simple-var-store.go
+package expr
+
+import "fmt"
+
+type SimpleVarStore struct {
+	varStore map[string]any
+}
+
+func NewSimpleVarStore() *SimpleVarStore {
+	return &SimpleVarStore{
+		varStore: make(map[string]any),
+	}
+}
+
+func (ctx *SimpleVarStore) Clone() (clone ExprContext) {
+	clone = &SimpleVarStore{
+		varStore: CloneMap(ctx.varStore),
+	}
+	return clone
+}
+
+func (ctx *SimpleVarStore) GetVar(varName string) (v any, exists bool) {
+	v, exists = ctx.varStore[varName]
+	return
+}
+
+func (ctx *SimpleVarStore) setVar(varName string, value any) {
+	ctx.varStore[varName] = value
+}
+
+func (ctx *SimpleVarStore) SetVar(varName string, value any) {
+	if allowedValue, ok := fromGenericAny(value); ok {
+		ctx.varStore[varName] = allowedValue
+	} else {
+		panic(fmt.Errorf("unsupported type %T of value %v", value, value))
+	}
+}
+
+func (ctx *SimpleVarStore) EnumVars(acceptor func(name string) (accept bool)) (varNames []string) {
+	varNames = make([]string, 0)
+	for name := range ctx.varStore {
+		if acceptor != nil {
+			if acceptor(name) {
+				varNames = append(varNames, name)
+			}
+		} else {
+			varNames = append(varNames, name)
+		}
+	}
+	return
+}
+
+func (ctx *SimpleVarStore) GetFuncInfo(name string) (f ExprFunc) {
+	return
+}
+
+func (ctx *SimpleVarStore) Call(name string, args []any) (result any, err error) {
+	return
+}
+
+func (ctx *SimpleVarStore) RegisterFunc(name string, functor Functor, minArgs, maxArgs int) {
+}
+
+func (ctx *SimpleVarStore) EnumFuncs(acceptor func(name string) (accept bool)) (funcNames []string) {
+	return
+}

symbol-map.go

@@ -1,198 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// Symbol.go
-package expr
-
-import (
-	"strings"
-)
-
-var symbolMap map[Symbol]symbolSpec
-
-type symbolClass int16
-
-const (
-	symClassOperator symbolClass = iota
-	symClassCommand
-	symClassIdentifier
-	symClassDelimiter
-	symClassParenthesis
-	symClassDeclaration
-	symClassValue
-	symClassOther
-)
-
-type symbolSpec struct {
-	repr   string
-	kind   symbolClass
-	opType termPosition
-}
-
-func init() {
-
-	symbolMap = map[Symbol]symbolSpec{
-		SymUnknown:            {"<unknown>", symClassOther, posLeaf},  //  -1: Unknown symbol
-		SymNone:               {"<null>", symClassOther, posLeaf},     //   0: Null value for variable of type symbol
-		SymError:              {"<error>", symClassOther, posLeaf},    //   1: Error reading from stream
-		SymEos:                {"<eos>", symClassOther, posLeaf},      //   2: End of stream
-		SymMinus:              {"-", symClassOperator, posInfix},      //   3: '-'
-		SymMinusEqual:         {"-=", symClassOperator, posInfix},     //   4: '-='
-		SymDoubleMinus:        {"--", symClassOperator, posPostfix},   //   5: '--'
-		SymPlus:               {"+", symClassOperator, posInfix},      //   6: '+'
-		SymPlusEqual:          {"+=", symClassOperator, posInfix},     //   7: '+='
-		SymDoublePlus:         {"++", symClassOperator, posPostfix},   //   8: '++'
-		SymStar:               {"*", symClassOperator, posInfix},      //   9: '*'
-		SymDoubleStar:         {"**", symClassOperator, posInfix},     //  10: '**'
-		SymSlash:              {"/", symClassOperator, posInfix},      //  11: '/'
-		SymBackSlash:          {"\\", symClassOperator, posLeaf},      //  12: '\'
-		SymVertBar:            {"|", symClassOperator, posInfix},      //  13: '|'
-		SymDoubleVertBar:      {"||", symClassOperator, posInfix},     //  14: '||'
-		SymComma:              {",", symClassOperator, posInfix},      //  15: ','
-		SymColon:              {":", symClassOperator, posInfix},      //  16: ':'
-		SymSemiColon:          {";", symClassOperator, posInfix},      //  17: ';'
-		SymDot:                {".", symClassOperator, posInfix},      //  18: '.'
-		SymDotSlash:           {"./", symClassOperator, posInfix},     //  19: './'
-		SymQuote:              {"'", symClassDelimiter, posLeaf},      //  20: '\''
-		SymDoubleQuote:        {"\"", symClassDelimiter, posLeaf},     //  21: '"'
-		SymBackTick:           {"`", symClassDelimiter, posLeaf},      //  22: '`'
-		SymExclamation:        {"!", symClassOperator, posPostfix},    //  23: '!'
-		SymQuestion:           {"?", symClassOperator, posInfix},      //  24: '?'
-		SymAmpersand:          {"&", symClassOperator, posInfix},      //  25: '&'
-		SymDoubleAmpersand:    {"&&", symClassOperator, posInfix},     //  26: '&&'
-		SymPercent:            {"%", symClassOperator, posInfix},      //  27: '%'
-		SymAt:                 {"@", symClassOperator, posPrefix},     //  28: '@'
-		SymUndescore:          {"_", symClassIdentifier, posLeaf},     //  29: '_'
-		SymEqual:              {"=", symClassOperator, posInfix},      //  30: '='
-		SymDoubleEqual:        {"==", symClassOperator, posInfix},     //  31: '=='
-		SymLess:               {"<", symClassOperator, posInfix},      //  32: '<'
-		SymLessOrEqual:        {"<=", symClassOperator, posInfix},     //  33: '<='
-		SymGreater:            {">", symClassOperator, posInfix},      //  34: '>'
-		SymGreaterOrEqual:     {">=", symClassOperator, posInfix},     //  35: '>='
-		SymLessGreater:        {"<>", symClassOperator, posInfix},     //  36: '<>'
-		SymNotEqual:           {"!=", symClassOperator, posInfix},     //  37: '!='
-		SymDollar:             {"$", symClassOperator, posPrefix},     //  38: '$'
-		SymHash:               {"#", symClassOperator, posPrefix},     //  39: '#'
-		SymOpenRound:          {"(", symClassParenthesis, posPrefix},  //  40: '('
-		SymClosedRound:        {")", symClassParenthesis, posPostfix}, //  41: ')'
-		SymOpenSquare:         {"[", symClassParenthesis, posPrefix},  //  42: '['
-		SymClosedSquare:       {"]", symClassParenthesis, posPostfix}, //  43: ']'
-		SymOpenBrace:          {"{", symClassParenthesis, posPrefix},  //  44: '{'
-		SymClosedBrace:        {"}", symClassParenthesis, posPostfix}, //  45: '}'
-		SymTilde:              {"~", symClassOperator, posPrefix},     //  46: '~'
-		SymDoubleQuestion:     {"??", symClassOperator, posInfix},     //  47: '??'
-		SymQuestionEqual:      {"?=", symClassOperator, posInfix},     //  48: '?='
-		SymQuestionExclam:     {"?!", symClassOperator, posInfix},     //  49: '?!'
-		SymDoubleAt:           {"@@", symClassCommand, posLeaf},       //  50: '@@'
-		SymDoubleColon:        {"::", symClassOperator, posInfix},     //  51: '::'
-		SymDoubleGreater:      {">>", symClassOperator, posInfix},     //  52: '>>'
-		SymDoubleLess:         {"<<", symClassOperator, posInfix},     //  53: '<<'
-		SymCaret:              {"^", symClassOperator, posInfix},      //  54: '^'
-		SymDollarRound:        {"$(", symClassOperator, posPrefix},    //  55: '$('
-		SymOpenClosedRound:    {"()", symClassOperator, posPostfix},   //  56: '()'
-		SymDoubleDollar:       {"$$", symClassCommand, posLeaf},       //  57: '$$'
-		SymDoubleDot:          {"..", symClassOperator, posInfix},     //  58: '..'
-		SymTripleDot:          {"...", symClassOperator, posPostfix},  //  59: '...'
-		SymStarEqual:          {"*=", symClassOperator, posInfix},     //  60: '*='
-		SymSlashEqual:         {"/=", symClassOperator, posInfix},     //  61: '/='
-		SymPercEqual:          {"%=", symClassOperator, posInfix},     //  62: '%='
-		SymDoubleLessEqual:    {"<<=", symClassOperator, posInfix},    //  63: '<<='
-		SymDoubleGreaterEqual: {">>=", symClassOperator, posInfix},    //  64: '>>='
-		SymAmpersandEqual:     {"&=", symClassOperator, posInfix},     //  65: '&='
-		SymVertBarEqual:       {"|=", symClassOperator, posInfix},     //  65: '|='
-		SymCaretEqual:         {"^=", symClassOperator, posInfix},     //  66: '^='
-		SymPlusGreater:        {"+>", symClassOperator, posInfix},     //  67: '+>'
-		SymLessPlus:           {"<+", symClassOperator, posInfix},     //  68: '<+'
-		SymPreInc:             {"++", symClassOperator, posPrefix},    //    : '++'
-		SymPreDec:             {"--", symClassOperator, posPrefix},    //    : '--'
-		// SymChangeSign
-		// SymUnchangeSign
-		// SymIdentifier
-		// SymBool
-		// SymInteger
-		// SymVariable
-		// SymFloat
-		// SymFraction
-		// SymString
-		// SymIterator
-		// SymOr:  "or",
-		// SymAnd: "and",
-		// SymNot: "not",
-		// SymComment
-		// SymFuncCall
-		// SymFuncDef
-		// SymList
-		// SymDict
-		// SymIndex
-		// SymExpression
-		// SymSelector     // <selector> ::= <expr> "?" <selector-case> {":" <selector-case>} ["::" <default-selector-case>]
-		// SymSelectorCase // <selector-case> ::= [<list>] "{" <multi-expr> "}"
-		// // SymOpenComment                       //   0: '/*'
-		// // SymClosedComment                     //   0: '*/'
-		// // SymOneLineComment                    //   0: '//'
-		// keywordBase
-		SymKwAnd:     {"and", symClassOperator, posInfix},
-		SymKwNot:     {"not", symClassOperator, posInfix},
-		SymKwOr:      {"or", symClassOperator, posInfix},
-		SymKwBut:     {"but", symClassOperator, posInfix},
-		SymKwFunc:    {"func(", symClassDeclaration, posPrefix},
-		SymKwBuiltin: {"builtin", symClassOperator, posPrefix},
-		SymKwPlugin:  {"plugin", symClassOperator, posPrefix},
-		SymKwIn:      {"in", symClassOperator, posInfix},
-		SymKwInclude: {"include", symClassOperator, posPrefix},
-		SymKwNil:     {"nil", symClassValue, posLeaf},
-		SymKwUnset:   {"unset", symClassOperator, posPrefix},
-	}
-}
-
-func SymToString(sym Symbol) string {
-	if s, ok := symbolMap[sym]; ok {
-		return s.repr
-	}
-	return ""
-}
-
-func SymListToString(symList []Symbol, quote bool) string {
-	var sb strings.Builder
-	if len(symList) == 0 {
-		sb.WriteString("<nothing>")
-	} else {
-		for _, sym := range symList {
-			if sb.Len() > 0 {
-				sb.WriteByte(',')
-				sb.WriteByte(' ')
-			}
-			if quote {
-				sb.WriteByte('`')
-			}
-			sb.WriteString(SymToString(sym))
-			if quote {
-				sb.WriteByte('`')
-			}
-		}
-	}
-	return sb.String()
-}
-
-func StringEndsWithOperator(s string) bool {
-	return endingOperator(s) != SymNone
-}
-
-func endingOperator(s string) (sym Symbol) {
-	var matchLength = 0
-	sym = SymNone
-	lower := strings.TrimRight(strings.ToLower(s), " \t")
-	for symbol, spec := range symbolMap {
-		if strings.HasSuffix(lower, spec.repr) {
-			if len(spec.repr) > matchLength {
-				matchLength = len(spec.repr)
-				if spec.kind == symClassOperator && (spec.opType == posInfix || spec.opType == posPrefix) {
-					sym = symbol
-				} else {
-					sym = SymNone
-				}
-			}
-		}
-	}
-	return
-}

symbol.go

@@ -33,7 +33,7 @@ const (
 	SymBackTick                          //  22: '`'
 	SymExclamation                       //  23: '!'
 	SymQuestion                          //  24: '?'
-	SymAmpersand                            //  25: '&'
+	SymAmpersand                         //  25: '&&'
 	SymDoubleAmpersand                   //  26: '&&'
 	SymPercent                           //  27: '%'
 	SymAt                                //  28: '@'
@@ -57,40 +57,17 @@ const (
 	SymTilde                             //  46: '~'
 	SymDoubleQuestion                    //  47: '??'
 	SymQuestionEqual                     //  48: '?='
-	SymQuestionExclam                       //  49: '?!'
+	SymDoubleAt                          //  49: '@@'
-	SymDoubleAt                             //  50: '@@'
+	SymDoubleColon                       //  50: '::'
-	SymDoubleColon                          //  51: '::'
+	SymInsert                            //  51: '>>'
-	SymDoubleGreater                        //  52: '>>'
+	SymAppend                            //  52: '<<'
-	SymDoubleLess                           //  53: '<<'
-	SymCaret                                //  54: '^'
-	SymDollarRound                          //  55: '$('
-	SymOpenClosedRound                      //  56: '()'
-	SymDoubleDollar                         //  57: '$$'
-	SymDoubleDot                            //  58: '..'
-	SymTripleDot                            //  59: '...'
-	SymStarEqual                            //  60: '*='
-	SymSlashEqual                           //  61: '/='
-	SymPercEqual                            //  62: '%='
-	SymDoubleLessEqual                      //  63: '<<='
-	SymDoubleGreaterEqual                   //  64: '>>='
-	SymAmpersandEqual                       //  65: '&='
-	SymVertBarEqual                         //  65: '|='
-	SymCaretEqual                           //  66: '^='
-	SymPlusGreater                          //  67: '+>'
-	SymLessPlus                             //  68: '<+'
 	SymChangeSign
 	SymUnchangeSign
-	SymDereference
-	SymPreInc
-	SymPreDec
 	SymIdentifier
 	SymBool
 	SymInteger
-	SymVariable
 	SymFloat
-	SymFraction
 	SymString
-	SymIterator
 	SymOr
 	SymAnd
 	SymNot
@@ -98,9 +75,6 @@ const (
 	SymFuncCall
 	SymFuncDef
 	SymList
-	SymDict
-	SymIndex
-	SymRange // [index : index]
 	SymExpression
 	SymSelector     // <selector> ::= <expr> "?" <selector-case> {":" <selector-case>} ["::" <default-selector-case>]
 	SymSelectorCase // <selector-case> ::= [<list>] "{" <multi-expr> "}"
@@ -116,11 +90,6 @@ const (
 	SymKwBut
 	SymKwFunc
 	SymKwBuiltin
-	SymKwPlugin
-	SymKwIn
-	SymKwInclude
-	SymKwNil
-	SymKwUnset
 )
 
 var keywords map[string]Symbol
@@ -130,14 +99,9 @@ func init() {
 	keywords = map[string]Symbol{
 		"AND":     SymKwAnd,
 		"BUILTIN": SymKwBuiltin,
-		"PLUGIN":  SymKwPlugin,
 		"BUT":     SymKwBut,
 		"FUNC":    SymKwFunc,
-		"IN":      SymKwIn,
-		"INCLUDE": SymKwInclude,
 		"NOT":     SymKwNot,
 		"OR":      SymKwOr,
-		"NIL":     SymKwNil,
-		"UNSET":   SymKwUnset,
 	}
 }

t_bool_test.go

@@ -1,67 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// t_bool_test.go
-package expr
-
-import (
-	"errors"
-	"testing"
-)
-
-func TestBool(t *testing.T) {
-	section := "Bool"
-	inputs := []inputType{
-		/*   1 */ {`true`, true, nil},
-		/*   2 */ {`false`, false, nil},
-		/*   3 */ {`not false`, true, nil},
-		/*   4 */ {`not 1`, false, nil},
-		/*   5 */ {`not "true"`, false, nil},
-		/*   6 */ {`not "false"`, false, nil},
-		/*   7 */ {`not ""`, true, nil},
-		/*   8 */ {`not []`, nil, errors.New(`[1:4] prefix/postfix operator "NOT" do not support operand '[]' [list]`)},
-		/*   9 */ {`true and false`, false, nil},
-		/*  10 */ {`true and []`, nil, errors.New(`[1:9] left operand 'true' [bool] and right operand '[]' [list] are not compatible with operator "AND"`)},
-		/*  11 */ {`[] and false`, nil, errors.New(`got list as left operand type of 'AND' operator, it must be bool`)},
-		/*  12 */ {`true or false`, true, nil},
-		/*  13 */ {`true or []`, true, nil},
-		/*  14 */ {`[] or false`, nil, errors.New(`got list as left operand type of 'OR' operator, it must be bool`)},
-		/*  15 */ {`!true`, false, nil},
-		/*  13 */ //{`true or []`, nil, errors.New(`[1:8] left operand 'true' [bool] and right operand '[]' [list] are not compatible with operator "OR"`)},
-	}
-
-	// t.Setenv("EXPR_PATH", ".")
-
-	// runTestSuiteSpec(t, section, inputs, 15)
-	runTestSuite(t, section, inputs)
-}
-
-func TestBoolNoShortcut(t *testing.T) {
-	section := "Bool-NoShortcut"
-	inputs := []inputType{
-		/*   1 */ {`true`, true, nil},
-		/*   2 */ {`false`, false, nil},
-		/*   3 */ {`not false`, true, nil},
-		/*   4 */ {`not 1`, false, nil},
-		/*   5 */ {`not "true"`, false, nil},
-		/*   6 */ {`not "false"`, false, nil},
-		/*   7 */ {`not ""`, true, nil},
-		/*   8 */ {`not []`, nil, `[1:4] prefix/postfix operator "NOT" do not support operand '[]' [list]`},
-		/*   9 */ {`true and false`, false, nil},
-		/*  10 */ {`true and []`, nil, `[1:9] left operand 'true' [bool] and right operand '[]' [list] are not compatible with operator "AND"`},
-		/*  11 */ {`[] and false`, nil, `[1:7] left operand '[]' [list] and right operand 'false' [bool] are not compatible with operator "AND"`},
-		/*  12 */ {`true or false`, true, nil},
-		/*  13 */ {`true or []`, nil, `[1:8] left operand 'true' [bool] and right operand '[]' [list] are not compatible with operator "OR"`},
-		/*  14 */ {`[] or false`, nil, `[1:6] left operand '[]' [list] and right operand 'false' [bool] are not compatible with operator "OR"`},
-	}
-
-	// t.Setenv("EXPR_PATH", ".")
-
-	ctx := NewSimpleStore()
-	current := SetCtrl(ctx, ControlBoolShortcut, false)
-
-	// runCtxTestSuiteSpec(t, ctx, section, inputs, 1)
-	runCtxTestSuite(t, ctx, section, inputs)
-
-	SetCtrl(ctx, ControlBoolShortcut, current)
-}

t_builtin-base_test.go

@@ -1,67 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// t_builtin-base_test.go
-package expr
-
-import (
-	"testing"
-)
-
-func TestFuncBase(t *testing.T) {
-	section := "Builtin-Base"
-
-	inputs := []inputType{
-		/*   1 */ {`isNil(nil)`, true, nil},
-		/*   2 */ {`v=nil; isNil(v)`, true, nil},
-		/*   3 */ {`v=5; isNil(v)`, false, nil},
-		/*   4 */ {`int(true)`, int64(1), nil},
-		/*   5 */ {`int(false)`, int64(0), nil},
-		/*   6 */ {`int(3.1)`, int64(3), nil},
-		/*   7 */ {`int(3.9)`, int64(3), nil},
-		/*   8 */ {`int("432")`, int64(432), nil},
-		/*   9 */ {`int("1.5")`, nil, `strconv.Atoi: parsing "1.5": invalid syntax`},
-		/*  10 */ {`int("432", 4)`, nil, `int(): too many params -- expected 1, got 2`},
-		/*  11 */ {`int(nil)`, nil, `int(): can't convert nil to int`},
-		/*  12 */ {`isInt(2+1)`, true, nil},
-		/*  13 */ {`isInt(3.1)`, false, nil},
-		/*  14 */ {`isFloat(3.1)`, true, nil},
-		/*  15 */ {`isString("3.1")`, true, nil},
-		/*  16 */ {`isString("3" + 1)`, true, nil},
-		/*  17 */ {`isList(["3",  1])`, true, nil},
-		/*  18 */ {`isDict({"a":"3",  "b":1})`, true, nil},
-		/*  19 */ {`isFract(1:3)`, true, nil},
-		/*  20 */ {`isFract(3:1)`, false, nil},
-		/*  21 */ {`isRational(3:1)`, true, nil},
-		/*  22 */ {`fract("2.2(3)")`, newFraction(67, 30), nil},
-		/*  23 */ {`fract("1.21(3)")`, newFraction(91, 75), nil},
-		/*  24 */ {`fract(1.21(3))`, newFraction(91, 75), nil},
-		/*  25 */ {`fract(1.21)`, newFraction(121, 100), nil},
-		/*  26 */ {`dec(2)`, float64(2), nil},
-		/*  27 */ {`dec(2.0)`, float64(2), nil},
-		/*  28 */ {`dec("2.0")`, float64(2), nil},
-		/*  29 */ {`dec(true)`, float64(1), nil},
-		/*  30 */ {`dec(true")`, nil, "[1:11] expected one of `,`, `)`, got `\"`"},
-		/*  31 */ {`dec()`, nil, `dec(): too few params -- expected 1, got 0`},
-		/*  32 */ {`dec(1,2,3)`, nil, `dec(): too many params -- expected 1, got 3`},
-		/*  33 */ {`isBool(false)`, true, nil},
-		/*  34 */ {`fract(1:2)`, newFraction(1, 2), nil},
-		/*  35 */ {`fract(12,2)`, newFraction(6, 1), nil},
-		/*  36 */ {`bool(2)`, true, nil},
-		/*  37 */ {`bool(1:2)`, true, nil},
-		/*  38 */ {`bool(1.0)`, true, nil},
-		/*  39 */ {`bool("1")`, true, nil},
-		/*  40 */ {`bool(false)`, false, nil},
-		/*  41 */ {`bool([1])`, nil, `bool(): can't convert list to bool`},
-		/*  42 */ {`dec(false)`, float64(0), nil},
-		/*  43 */ {`dec(1:2)`, float64(0.5), nil},
-		/*  44 */ {`dec([1])`, nil, `dec(): can't convert list to float`},
-		/*  45 */ {`eval("a=3"); a`, int64(3), nil},
-		// /*  45 */ {`string([1])`, nil, `string(): can't convert list to string`},
-	}
-
-	t.Setenv("EXPR_PATH", ".")
-
-	// runTestSuiteSpec(t, section, inputs, 45)
-	runTestSuite(t, section, inputs)
-}

t_builtin-fmt_test.go

@@ -1,48 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// t_builtin-fmt.go
-package expr
-
-import (
-	// "errors"
-	"bytes"
-	"fmt"
-	"testing"
-)
-
-func TestFuncFmt(t *testing.T) {
-	section := "Builtin-Fmt"
-
-	inputs := []inputType{
-		/*   1 */ {`builtin "fmt"; print("ciao")`, int64(4), nil},
-		/*   2 */ {`builtin "fmt"; println(" ciao")`, int64(6), nil},
-	}
-
-	//t.Setenv("EXPR_PATH", ".")
-
-	// runTestSuiteSpec(t, section, inputs, 1)
-	runTestSuite(t, section, inputs)
-}
-
-func TestFmt(t *testing.T) {
-	section := "Builtin-Fmt"
-
-	text := "ciao mondo"
-	inputs := []inputType{
-		/*   1 */ {fmt.Sprintf(`builtin "fmt"; println("%s")`, text), int64(11), nil},
-	}
-
-	// t.Setenv("EXPR_PATH", ".")
-
-	var b bytes.Buffer
-	ctx := NewSimpleStore()
-	currentStdout := SetCtrl(ctx, ControlStdout, &b)
-
-	runCtxTestSuite(t, ctx, section, inputs)
-
-	SetCtrl(ctx, ControlStdout, currentStdout)
-	if b.String() != text+"\n" {
-		t.Errorf("println(): Got: %q, Want: %q", b.String(), text+"\n")
-	}
-}