fixed some defects in the iter-list implementation

common-errors.go

@@ -25,15 +25,11 @@ func errTooMuchParams(funcName string, maxArgs, argCount int) (err error) {
 // --- General errors
 
 func errCantConvert(funcName string, value any, kind string) error {
-	if typer, ok := value.(Typer); ok {
-		return fmt.Errorf("%s(): can't convert %s to %s", funcName, typer.TypeName(), kind)
-	} else {
-		return fmt.Errorf("%s(): can't convert %T to %s", funcName, value, kind)
-	}
+	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 %T (%v)", funcName, kind, value, value)
+	return fmt.Errorf("%s() expected %s, got %s (%v)", funcName, kind, typeName(value), value)
 }
 
 func errFuncDivisionByZero(funcName string) error {
@@ -46,18 +42,14 @@ func errDivisionByZero() error {
 
 // --- Parameter errors
 
-// func errOneParam(funcName string) error {
-// 	return fmt.Errorf("%s() requires exactly one param", funcName)
-// }
-
 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 %T (%v) for parameter %q", funcName, paramValue, paramValue, paramName)
+	return fmt.Errorf("%s() invalid value %s (%v) for parameter %q", funcName, typeName(paramValue), paramValue, paramName)
 }
 
 func errWrongParamType(funcName, paramName, paramType string, paramValue any) error {
-	return fmt.Errorf("%s() the %q parameter must be a %s, got a %T (%v)", funcName, paramName, paramType, paramValue, paramValue)
+	return fmt.Errorf("%s() the %q parameter must be a %s, got a %s (%v)", funcName, paramName, paramType, typeName(paramValue), paramValue)
 }

dict-type.go

@@ -0,0 +1,130 @@
+// 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 newDict(dictAny map[any]*term) (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 (dict *DictType) toMultiLine(sb *strings.Builder, indent int) {
+	sb.WriteString(strings.Repeat("\t", indent))
+	sb.WriteString("{\n")
+
+	first := true
+	for name, value := range *dict {
+		if first {
+			first = false
+		} else {
+			sb.WriteByte(',')
+			sb.WriteByte('\n')
+		}
+
+		sb.WriteString(strings.Repeat("\t", indent+1))
+		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(MultiLine))
+		} else if _, ok = value.(Functor); ok {
+			sb.WriteString("func(){}")
+		} else {
+			sb.WriteString(fmt.Sprintf("%v", value))
+		}
+	}
+	sb.WriteString(strings.Repeat("\t", indent))
+	sb.WriteString("\n}")
+}
+
+func (dict *DictType) ToString(opt FmtOpt) string {
+	var sb strings.Builder
+	if opt&MultiLine != 0 {
+		dict.toMultiLine(&sb, 0)
+	} 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
+}
+

formatter.go

@@ -51,8 +51,10 @@ type Typer interface {
 	TypeName() string
 }
 
-func getTypeName(v any) (name string) {
-	if typer, ok := v.(Typer); ok {
+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"

fraction-type.go

@@ -33,52 +33,10 @@ func float64ToFraction(f float64) (fract *FractionType, err error) {
 	}
 	dec := fmt.Sprintf("%.12f", decPart)
 	s := fmt.Sprintf("%s%.f%s", sign, intPart, dec[1:])
-	// fmt.Printf("S: '%s'\n",s)
 	return makeGeneratingFraction(s)
 }
 
 // Based on https://cs.opensource.google/go/go/+/refs/tags/go1.22.3:src/math/big/rat.go;l=39
-/*
-func _float64ToFraction(f float64) (num, den int64, err error) {
-	const expMask = 1<<11 - 1
-	bits := math.Float64bits(f)
-	mantissa := bits & (1<<52 - 1)
-	exp := int((bits >> 52) & expMask)
-	switch exp {
-	case expMask: // non-finite
-		err = errors.New("infite")
-		return
-	case 0: // denormal
-		exp -= 1022
-	default: // normal
-		mantissa |= 1 << 52
-		exp -= 1023
-	}
-
-	shift := 52 - exp
-
-	// Optimization (?): partially pre-normalise.
-	for mantissa&1 == 0 && shift > 0 {
-		mantissa >>= 1
-		shift--
-	}
-
-	if f < 0 {
-		num = -int64(mantissa)
-	} else {
-		num = int64(mantissa)
-	}
-	den = int64(1)
-
-	if shift > 0 {
-		den = den << shift
-	} else {
-		num = num << (-shift)
-	}
-	return
-}
-*/
-
 func makeGeneratingFraction(s string) (f *FractionType, err error) {
 	var num, den int64
 	var sign int64 = 1

global-context.go

@@ -40,11 +40,25 @@ func GetVar(ctx ExprContext, name string) (value any, exists bool) {
 	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, ownerCtx ExprContext) {
-	if item, exists = ctx.GetFuncInfo(name); exists {
-		ownerCtx = ctx
-	} else if item, exists = globalCtx.GetFuncInfo(name); exists {
-		ownerCtx = globalCtx
+	if len(name) > 0 {
+		if item, exists = GetLocalFuncInfo(ctx, name); exists {
+			ownerCtx = ctx
+		} else if item, exists = globalCtx.GetFuncInfo(name); exists {
+			ownerCtx = globalCtx
+		}
 	}
 	return
 }

iter-list.go

@@ -106,10 +106,19 @@ func (it *ListIterator) CallOperation(name string, args []any) (v any, err error
 
 func (it *ListIterator) Current() (item any, err error) {
 	a := *(it.a)
-	if it.index >= 0 && it.index <= it.stop {
-		item = a[it.index]
+	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 {
-		err = io.EOF
+		if it.start < len(a) && it.index >= it.stop && it.index <= it.start {
+			item = a[it.index]
+		} else {
+			err = io.EOF
+		}
+
 	}
 	return
 }

iterator.go

@@ -34,7 +34,7 @@ type ExtIterator interface {
 }
 
 func errNoOperation(name string) error {
-	return fmt.Errorf("no %q function defined in the data-source", name)
+	return fmt.Errorf("no %s() function defined in the data-source", name)
 }
 
 func errInvalidDataSource() error {

list-type.go

@@ -13,6 +13,9 @@ import (
 type ListType []any
 
 func newListA(listAny ...any) (list *ListType) {
+	if listAny == nil {
+		listAny = []any{}
+	}
 	return newList(listAny)
 }
 
@@ -147,3 +150,13 @@ func deepSame(a, b any, deepCmp deepFuncTemplate) (eq bool, err error) {
 
 	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-dict.go

@@ -4,124 +4,6 @@
 // operand-dict.go
 package expr
 
-import (
-	"fmt"
-	"reflect"
-	"strings"
-)
-
-type DictType map[any]any
-
-func newDict(dictAny map[any]*term) (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 (dict *DictType) toMultiLine(sb *strings.Builder, indent int) {
-	sb.WriteString(strings.Repeat("\t", indent))
-	sb.WriteString("{\n")
-
-	first := true
-	for name, value := range *dict {
-		if first {
-			first = false
-		} else {
-			sb.WriteByte(',')
-			sb.WriteByte('\n')
-		}
-
-		sb.WriteString(strings.Repeat("\t", indent+1))
-		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(MultiLine))
-		} else if _, ok = value.(Functor); ok {
-			sb.WriteString("func(){}")
-		} else {
-			sb.WriteString(fmt.Sprintf("%v", value))
-		}
-	}
-	sb.WriteString(strings.Repeat("\t", indent))
-	sb.WriteString("\n}")
-}
-
-func (dict *DictType) ToString(opt FmtOpt) string {
-	var sb strings.Builder
-	if opt&MultiLine != 0 {
-		dict.toMultiLine(&sb, 0)
-	} 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
-		}
-	}
-}
 
 // -------- dict term
 func newDictTerm(args map[any]*term) *term {

operand-func.go

@@ -40,7 +40,6 @@ func checkFunctionCall(ctx ExprContext, name string, varParams *[]any) (err erro
 			err = errTooMuchParams(name, info.MaxArgs(), len(*varParams))
 		}
 		if err == nil && owner != ctx {
-			// ctx.RegisterFunc(name, info.Functor(), info.MinArgs(), info.MaxArgs())
 			ctx.RegisterFuncInfo(info)
 		}
 	} else {
@@ -52,7 +51,6 @@ func checkFunctionCall(ctx ExprContext, name string, varParams *[]any) (err erro
 func evalFuncCall(parentCtx ExprContext, self *term) (v any, err error) {
 	ctx := cloneContext(parentCtx)
 	name, _ := self.tk.Value.(string)
-	// fmt.Printf("Call %s(), context: %p\n", name, ctx)
 	params := make([]any, len(self.children), len(self.children)+5)
 	for i, tree := range self.children {
 		var param any
@@ -85,20 +83,6 @@ func newFuncDefTerm(tk *Token, args []*term) *term {
 }
 
 // -------- eval func def
-// 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())
-// 		}
-// 		v = newExprFunctor(expr, paramList, ctx)
-// 	} else {
-// 		err = errors.New("invalid function definition: the body specification must be an expression")
-// 	}
-// 	return
-// }
-
 func evalFuncDef(ctx ExprContext, self *term) (v any, err error) {
 	bodySpec := self.value()
 	if expr, ok := bodySpec.(*ast); ok {

operand-iterator.go

@@ -148,23 +148,6 @@ func evalIterator(ctx ExprContext, self *term) (v any, err error) {
 	return
 }
 
-// func evalChildren(ctx ExprContext, terms []*term, firstChildValue any) (list *ListType, err error) {
-// 	items := make(ListType, len(terms))
-// 	for i, tree := range terms {
-// 		var param any
-// 		if i == 0 && firstChildValue != nil {
-// 			param = firstChildValue
-// 		} else if param, err = tree.compute(ctx); err != nil {
-// 			break
-// 		}
-// 		items[i] = param
-// 	}
-// 	if err == nil {
-// 		list = &items
-// 	}
-// 	return
-// }
-
 func evalSibling(ctx ExprContext, terms []*term, firstChildValue any) (list []any, err error) {
 	items := make([]any, 0, len(terms))
 	for i, tree := range terms {

operator-assign.go

@@ -16,14 +16,59 @@ func newAssignTerm(tk *Token) (inst *term) {
 	}
 }
 
+func assignCollectionItem(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 {
+			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, self *term) (v any, err error) {
 	if err = self.checkOperands(); err != nil {
 		return
 	}
 
 	leftTerm := self.children[0]
-	if leftTerm.tk.Sym != SymVariable {
-		err = leftTerm.tk.Errorf("left operand of %q must be a variable", self.tk.source)
+	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", self.tk.source)
 		return
 	}
 
@@ -31,22 +76,22 @@ func evalAssign(ctx ExprContext, self *term) (v any, err error) {
 
 	if v, err = rightChild.compute(ctx); err == nil {
 		if functor, ok := v.(Functor); ok {
-			funcName := rightChild.source()
-			if info, exists, _ := GetFuncInfo(ctx, funcName); exists {
-				// ctx.RegisterFuncInfo(info)
+			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, newFuncParam)
 				paramSpecs := ForAll(funcDef.params, func(p ExprFuncParam) ExprFuncParam { return p })
 
 				ctx.RegisterFunc(leftTerm.source(), functor, typeAny, paramSpecs)
 			} else {
-				err = self.Errorf("unknown function %s()", funcName)
+				err = self.Errorf("unknown function %s()", rightChild.source())
 			}
 		} else {
-			ctx.UnsafeSetVar(leftTerm.source(), v)
+			err = assignValue(ctx, leftTerm, v)
 		}
 	}
+	if err != nil {
+		v = nil
+	}
 	return
 }
 

parser.go

@@ -6,7 +6,6 @@ package expr
 
 import (
 	"errors"
-	"fmt"
 )
 
 //-------- parser
@@ -335,7 +334,7 @@ func (self *parser) parseGeneral(scanner *scanner, allowForest bool, allowVarRef
 	var tk *Token
 	tree = NewAst()
 	firstToken := true
-	lastSym := SymUnknown
+	// lastSym := SymUnknown
 	for tk = scanner.Next(); err == nil && tk != nil && !tk.IsTerm(termSymbols); tk = scanner.Next() {
 		if tk.Sym == SymComment {
 			continue
@@ -404,9 +403,9 @@ func (self *parser) parseGeneral(scanner *scanner, allowForest bool, allowVarRef
 				}
 			}
 		case SymEqual:
-			if err = checkPrevSymbol(lastSym, SymIdentifier, tk); err == nil {
-				currentTerm, err = tree.addToken2(tk)
-			}
+			// if err = checkPrevSymbol(lastSym, SymIdentifier, tk); err == nil {
+			currentTerm, err = tree.addToken2(tk)
+			// }
 		case SymFuncDef:
 			var funcDefTerm *term
 			if funcDefTerm, err = self.parseFuncDef(scanner); err == nil {
@@ -450,7 +449,7 @@ func (self *parser) parseGeneral(scanner *scanner, allowForest bool, allowVarRef
 			selectorTerm = nil
 
 		}
-		lastSym = tk.Sym
+		// lastSym = tk.Sym
 	}
 	if err == nil {
 		err = tk.Error()
@@ -458,9 +457,9 @@ func (self *parser) parseGeneral(scanner *scanner, allowForest bool, allowVarRef
 	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
-}
+// 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
+// }

simple-func-store.go.bak

@@ -1,244 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// simple-func-store.go
-package expr
-
-import (
-	"fmt"
-	"slices"
-	"strings"
-)
-
-type SimpleFuncStore struct {
-	SimpleVarStore
-	funcStore map[string]*funcInfo
-}
-
-type paramFlags uint16
-
-const (
-	pfOptional paramFlags = 1 << iota
-	pfRepeat
-)
-
-type funcParamInfo struct {
-	name         string
-	flags        paramFlags
-	defaultValue any
-}
-
-func newFuncParam(name string) *funcParamInfo {
-	return &funcParamInfo{name: name}
-}
-
-func newFuncParamFlag(name string, flags paramFlags) *funcParamInfo {
-	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 "any"
-}
-
-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
-}
-
-type funcInfo struct {
-	name       string
-	minArgs    int
-	maxArgs    int
-	functor    Functor
-	params     []ExprFuncParam
-	returnType string
-}
-
-func (info *funcInfo) Params() []ExprFuncParam {
-	return info.params
-}
-
-func (info *funcInfo) ReturnType() string {
-	return info.returnType
-}
-
-func (info *funcInfo) ToString(opt FmtOpt) string {
-	var sb strings.Builder
-	sb.WriteByte('(')
-	if info.params != nil {
-		for i, p := range info.params {
-			if i > 0 {
-				sb.WriteString(", ")
-			}
-			sb.WriteString(p.Name())
-			if p.IsOptional() {
-				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)
-	}
-	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 NewSimpleFuncStore() *SimpleFuncStore {
-	ctx := &SimpleFuncStore{
-		SimpleVarStore: SimpleVarStore{varStore: make(map[string]any)},
-		funcStore:      make(map[string]*funcInfo),
-	}
-	//ImportBuiltinsFuncs(ctx)
-	return ctx
-}
-
-func (ctx *SimpleFuncStore) Clone() ExprContext {
-	svs := ctx.SimpleVarStore
-	return &SimpleFuncStore{
-		// SimpleVarStore: SimpleVarStore{varStore: CloneMap(ctx.varStore)},
-		SimpleVarStore: SimpleVarStore{varStore: svs.cloneVars()},
-		funcStore:      CloneFilteredMap(ctx.funcStore, func(name string) bool { return name[0] != '@' }),
-	}
-}
-
-func funcsCtxToBuilder(sb *strings.Builder, ctx ExprContext, indent int) {
-	sb.WriteString("funcs: {\n")
-	first := true
-	names := ctx.EnumFuncs(func(name string) bool { return true })
-	slices.Sort(names)
-	for _, name := range names {
-		if first {
-			first = false
-		} else {
-			sb.WriteByte(',')
-			sb.WriteByte('\n')
-		}
-		value, _ := ctx.GetFuncInfo(name)
-		sb.WriteString(strings.Repeat("\t", indent+1))
-		sb.WriteString(name)
-		//sb.WriteString("=")
-		if formatter, ok := value.(Formatter); ok {
-			sb.WriteString(formatter.ToString(0))
-		} else {
-			sb.WriteString(fmt.Sprintf("%v", value))
-		}
-	}
-	sb.WriteString("\n}\n")
-}
-
-func (ctx *SimpleFuncStore) ToString(opt FmtOpt) string {
-	var sb strings.Builder
-	sb.WriteString(ctx.SimpleVarStore.ToString(opt))
-	funcsCtxToBuilder(&sb, ctx, 0)
-	return sb.String()
-}
-
-func (ctx *SimpleFuncStore) GetFuncInfo(name string) (info ExprFunc, exists bool) {
-	info, exists = 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) RegisterFuncInfo(info ExprFunc) {
-	ctx.funcStore[info.Name()], _ = info.(*funcInfo)
-}
-
-func (ctx *SimpleFuncStore) RegisterFunc2(name string, functor Functor, returnType string, params []ExprFuncParam) error {
-	var minArgs = 0
-	var maxArgs = 0
-	if params != nil {
-		for _, p := range params {
-			if maxArgs == -1 {
-				return fmt.Errorf("no more params can be specified after the ellipsis symbol: %q", p.Name())
-				// } else if p.IsRepeat() {
-				// 	maxArgs = -1
-				// 	continue
-			}
-			if p.IsOptional() {
-				maxArgs++
-			} else if maxArgs == minArgs {
-				minArgs++
-				maxArgs++
-			} else {
-				return fmt.Errorf("can't specify non-optional param after optional ones: %q", p.Name())
-			}
-			if p.IsRepeat() {
-				maxArgs = -1
-			}
-		}
-	}
-	ctx.funcStore[name] = &funcInfo{
-		name: name, minArgs: minArgs, maxArgs: maxArgs, functor: functor, returnType: returnType, params: params,
-	}
-	return nil
-}
-
-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

@@ -172,7 +172,7 @@ func (ctx *SimpleStore) EnumFuncs(acceptor func(name string) (accept bool)) (fun
 }
 
 func (ctx *SimpleStore) Call(name string, args []any) (result any, err error) {
-	if info, exists := ctx.funcStore[name]; exists {
+	if info, exists := GetLocalFuncInfo(ctx, name); exists {
 		functor := info.Functor()
 		result, err = functor.Invoke(ctx, name, args)
 	} else {

simple-var-store.go.bak

@@ -1,126 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// simple-var-store.go
-package expr
-
-import (
-	"fmt"
-	"strings"
-)
-
-type SimpleVarStore struct {
-	varStore map[string]any
-}
-
-func NewSimpleVarStore() *SimpleVarStore {
-	return &SimpleVarStore{
-		varStore: make(map[string]any),
-	}
-}
-
-func (ctx *SimpleVarStore) cloneVars() (vars map[string]any) {
-	return CloneFilteredMap(ctx.varStore, func(name string) bool { return name[0] != '@' })
-}
-
-func (ctx *SimpleVarStore) Clone() (clone ExprContext) {
-	// fmt.Println("*** Cloning context ***")
-	clone = &SimpleVarStore{
-		varStore: ctx.cloneVars(),
-	}
-	return clone
-}
-
-func (ctx *SimpleVarStore) GetVar(varName string) (v any, exists bool) {
-	v, exists = ctx.varStore[varName]
-	return
-}
-
-func (ctx *SimpleVarStore) UnsafeSetVar(varName string, value any) {
-	// fmt.Printf("[%p] setVar(%v, %v)\n", ctx, varName, value)
-	ctx.varStore[varName] = value
-}
-
-func (ctx *SimpleVarStore) 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 *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, exists bool) {
-	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) RegisterFuncInfo(info ExprFunc) {
-}
-func (ctx *SimpleVarStore) RegisterFunc2(name string, f Functor, returnType string, param []ExprFuncParam) error {
-	return nil
-}
-
-func (ctx *SimpleVarStore) EnumFuncs(acceptor func(name string) (accept bool)) (funcNames []string) {
-	return
-}
-
-func varsCtxToBuilder(sb *strings.Builder, ctx ExprContext, indent int) {
-	sb.WriteString("vars: {\n")
-	first := true
-	for _, name := range ctx.EnumVars(func(name string) bool { return name[0] != '_' }) {
-		if first {
-			first = false
-		} else {
-			sb.WriteByte(',')
-			sb.WriteByte('\n')
-		}
-
-		value, _ := ctx.GetVar(name)
-		sb.WriteString(strings.Repeat("\t", indent+1))
-		sb.WriteString(name)
-		sb.WriteString(": ")
-		if f, ok := value.(Formatter); ok {
-			sb.WriteString(f.ToString(0))
-		} else if _, ok = value.(Functor); ok {
-			sb.WriteString("func(){}")
-			// } else if _, ok = value.(map[any]any); ok {
-			// 	sb.WriteString("dict{}")
-		} else {
-			sb.WriteString(fmt.Sprintf("%v", value))
-		}
-	}
-	sb.WriteString(strings.Repeat("\t", indent))
-	sb.WriteString("\n}\n")
-}
-
-func varsCtxToString(ctx ExprContext, indent int) string {
-	var sb strings.Builder
-	varsCtxToBuilder(&sb, ctx, indent)
-	return sb.String()
-}
-
-func (ctx *SimpleVarStore) ToString(opt FmtOpt) string {
-	var sb strings.Builder
-	varsCtxToBuilder(&sb, ctx, 0)
-	return sb.String()
-}

t_dict_test.go

@@ -28,6 +28,9 @@ func TestDictParser(t *testing.T) {
 		/*  5 */ {`#{1:"one",2:"two",3:"three"}`, int64(3), nil},
 		/*  6 */ {`{1:"one"} + {2:"two"}`, map[any]any{1: "one", 2: "two"}, nil},
 		/*  7 */ {`2 in {1:"one", 2:"two"}`, true, nil},
+		/*  8 */ {`D={"a":1, "b":2}; D["a"]=9; D`, map[any]any{"a": 9, "b": 2}, nil},
+		/*  9 */ {`D={"a":1, "b":2}; D["z"]=9; D`, map[any]any{"z": 9, "a": 1, "b": 2}, nil},
+		/* 10 */ {`D={"a":1, "b":2}; D[nil]=9`, nil, errors.New(`[1:21] index/key is nil`)},
 	}
 
 	succeeded := 0

t_func-base_test.go

@@ -23,7 +23,7 @@ func TestFuncBase(t *testing.T) {
 		/*   8 */ {`int("432")`, int64(432), nil},
 		/*   9 */ {`int("1.5")`, nil, errors.New(`strconv.Atoi: parsing "1.5": invalid syntax`)},
 		/*  10 */ {`int("432", 4)`, nil, errors.New(`int(): too much params -- expected 1, got 2`)},
-		/*  11 */ {`int(nil)`, nil, errors.New(`int(): can't convert <nil> to int`)},
+		/*  11 */ {`int(nil)`, nil, errors.New(`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},

t_func-string_test.go

@@ -16,8 +16,8 @@ func TestFuncString(t *testing.T) {
 		/*   1 */ {`builtin "string"; joinStr("-", "one", "two", "three")`, "one-two-three", nil},
 		/*   2 */ {`builtin "string"; joinStr("-", ["one", "two", "three"])`, "one-two-three", nil},
 		/*   3 */ {`builtin "string"; ls= ["one", "two", "three"]; joinStr("-", ls)`, "one-two-three", nil},
-		/*   4 */ {`builtin "string"; ls= ["one", "two", "three"]; joinStr(1, ls)`, nil, errors.New(`joinStr() the "separator" parameter must be a string, got a int64 (1)`)},
-		/*   5 */ {`builtin "string"; ls= ["one", 2, "three"]; joinStr("-", ls)`, nil, errors.New(`joinStr() expected string, got int64 (2)`)},
+		/*   4 */ {`builtin "string"; ls= ["one", "two", "three"]; joinStr(1, ls)`, nil, errors.New(`joinStr() the "separator" parameter must be a string, got a integer (1)`)},
+		/*   5 */ {`builtin "string"; ls= ["one", 2, "three"]; joinStr("-", ls)`, nil, errors.New(`joinStr() expected string, got integer (2)`)},
 		/*   6 */ {`builtin "string"; "<"+trimStr("  bye bye  ")+">"`, "<bye bye>", nil},
 		/*   7 */ {`builtin "string"; subStr("0123456789", 1,2)`, "12", nil},
 		/*   8 */ {`builtin "string"; subStr("0123456789", -3,2)`, "78", nil},
@@ -30,7 +30,7 @@ func TestFuncString(t *testing.T) {
 		/*  15 */ {`builtin "string"; endsWithStr("0123456789", "xyz", "0125")`, false, nil},
 		/*  16 */ {`builtin "string"; endsWithStr("0123456789")`, nil, errors.New(`endsWithStr(): too few params -- expected 2 or more, got 1`)},
 		/*  17 */ {`builtin "string"; splitStr("one-two-three", "-")`, newListA("one", "two", "three"), nil},
-		/*  18 */ {`builtin "string"; joinStr("-", [1, "two", "three"])`, nil, errors.New(`joinStr() expected string, got int64 (1)`)},
+		/*  18 */ {`builtin "string"; joinStr("-", [1, "two", "three"])`, nil, errors.New(`joinStr() expected string, got integer (1)`)},
 		/*  19 */ {`builtin "string"; joinStr()`, nil, errors.New(`joinStr(): too few params -- expected 1 or more, got 0`)},
 
 		/*  69 */ /*{`builtin "string"; $$global`, `vars: {

t_list_test.go

@@ -13,26 +13,26 @@ import (
 func TestListParser(t *testing.T) {
 	section := "List"
 
-	type inputType struct {
-		source     string
-		wantResult any
-		wantErr    error
-	}
-
+	/*	type inputType struct {
+			source     string
+			wantResult any
+			wantErr    error
+		}
+	*/
 	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},
+		/*   1 */ {`[]`, newListA(), nil},
+		/*   2 */ {`[1,2,3]`, newListA(int64(1), int64(2), int64(3)), nil},
+		/*   3 */ {`[1,2,"hello"]`, newListA(int64(1), int64(2), "hello"), nil},
+		/*   4 */ {`[1+2, not true, "hello"]`, newListA(int64(3), false, "hello"), nil},
+		/*   5 */ {`[1,2]+[3]`, newListA(int64(1), int64(2), int64(3)), nil},
+		/*   6 */ {`[1,4,3,2]-[3]`, newListA(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 (2 in 1) has wrong type string, number expected`)},
 		/*  11 */ {`[a=1,b=2,c=3] but a+b+c`, int64(6), nil},
-		/*  12 */ {`[1,2,3] << 2+2`, []any{int64(1), int64(2), int64(3), int64(4)}, nil},
-		/*  13 */ {`2-1 >> [2,3]`, []any{int64(1), int64(2), int64(3)}, nil},
+		/*  12 */ {`[1,2,3] << 2+2`, newListA(int64(1), int64(2), int64(3), int64(4)), nil},
+		/*  13 */ {`2-1 >> [2,3]`, newListA(int64(1), int64(2), int64(3)), nil},
 		/*  14 */ {`[1,2,3][1]`, int64(2), nil},
 		/*  15 */ {`ls=[1,2,3] but ls[1]`, int64(2), nil},
 		/*  16 */ {`ls=[1,2,3] but ls[-1]`, int64(3), nil},
@@ -41,22 +41,30 @@ func TestListParser(t *testing.T) {
 		/*  19 */ {`["a", "b", "c"]`, newList([]any{"a", "b", "c"}), nil},
 		/*  20 */ {`#["a", "b", "c"]`, int64(3), nil},
 		/*  21 */ {`"b" in ["a", "b", "c"]`, true, nil},
-		/*  22 */ {`a=[1,2]; (a)<<3`, []any{1, 2, 3}, nil},
-		/*  23 */ {`a=[1,2]; (a)<<3; 1`, []any{1, 2}, nil},
+		/*  22 */ {`a=[1,2]; (a)<<3`, newListA(int64(1), int64(2), int64(3)), nil},
+		/*  23 */ {`a=[1,2]; (a)<<3; a`, newListA(int64(1), int64(2)), nil},
 		/*  24 */ {`["a","b","c","d"][1]`, "b", nil},
 		/*  25 */ {`["a","b","c","d"][1,1]`, nil, errors.New(`[1:19] one index only is allowed`)},
-		/*  26 */ {`[0,1,2,3,4][:]`, ListType{int64(0), int64(1), int64(2), int64(3), int64(4)}, nil},
+		/*  26 */ {`[0,1,2,3,4][:]`, newListA(int64(0), int64(1), int64(2), int64(3), int64(4)), nil},
 		/*  27 */ {`["a", "b", "c"] << ;`, nil, errors.New(`[1:18] infix operator "<<" requires two non-nil operands, got 1`)},
 		/*  28 */ {`2 << 3;`, nil, errors.New(`[1:4] left operand '2' [integer] and right operand '3' [integer] are not compatible with operator "<<"`)},
 		/*  29 */ {`but >> ["a", "b", "c"]`, nil, errors.New(`[1:6] infix operator ">>" requires two non-nil operands, got 0`)},
 		/*  30 */ {`2 >> 3;`, nil, errors.New(`[1:4] left operand '2' [integer] and right operand '3' [integer] are not compatible with operator ">>"`)},
-		/*  31 */ {`a=[1,2]; a<<3`, []any{1, 2, 3}, nil},
-		/*  33 */ {`a=[1,2]; 5>>a`, []any{5, 1, 2}, nil},
-
+		/*  31 */ {`a=[1,2]; a<<3`, newListA(int64(1), int64(2), int64(3)), nil},
+		/*  33 */ {`a=[1,2]; 5>>a`, newListA(int64(5), int64(1), int64(2)), nil},
+		/*  34 */ {`L=[1,2]; L[0]=9; L`, newListA(int64(9), int64(2)), nil},
+		/*  35 */ {`L=[1,2]; L[5]=9; L`, nil, errors.New(`index 5 out of bounds (0, 1)`)},
+		/*  36 */ {`L=[1,2]; L[]=9; L`, nil, errors.New(`[1:12] index/key specification expected, got [] [list]`)},
+		/*  37 */ {`L=[1,2]; L[nil]=9;`, nil, errors.New(`[1:12] index/key is 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},
 	}
 
+	// t.Setenv("EXPR_PATH", ".")
+
+	// parserTestSpec(t, section, inputs, 17)
+	parserTest(t, section, inputs)
+	return
 	succeeded := 0
 	failed := 0
 

t_parser_test.go

@@ -18,6 +18,8 @@ type inputType struct {
 }
 
 func TestGeneralParser(t *testing.T) {
+	section := "Parser"
+
 	inputs := []inputType{
 		/*   1 */ {`1+/*5*/2`, int64(3), nil},
 		/*   2 */ {`3 == 4`, false, nil},
@@ -115,8 +117,8 @@ func TestGeneralParser(t *testing.T) {
 		/*  94 */ {`false or true`, true, nil},
 		/*  95 */ {`false or (x==2)`, nil, errors.New(`undefined variable or function "x"`)},
 		/*  96 */ {`a=5; a`, int64(5), nil},
-		/*  97 */ {`2=5`, nil, errors.New(`assign operator ("=") must be preceded by a variable`)},
-		/*  98 */ {`2+a=5`, nil, errors.New(`[1:3] left operand of "=" must be a variable`)},
+		/*  97 */ {`2=5`, nil, errors.New(`[1:2] left operand of "=" must be a variable or a collection's item`)},
+		/*  98 */ {`2+a=5`, nil, errors.New(`[1:3] left operand of "=" must be a variable or a collection's item`)},
 		/*  99 */ {`2+(a=5)`, int64(7), nil},
 		/* 100 */ {`x ?? "default"`, "default", nil},
 		/* 101 */ {`x="hello"; x ?? "default"`, "hello", nil},
@@ -145,8 +147,8 @@ func TestGeneralParser(t *testing.T) {
 	}
 
 	// t.Setenv("EXPR_PATH", ".")
-	// parserTestSpec(t, "General", inputs, 102)
-	parserTest(t, "General", inputs)
+	// parserTestSpec(t, section, inputs, 102)
+	parserTest(t, section, inputs)
 }
 
 func parserTestSpec(t *testing.T, section string, inputs []inputType, spec ...int) {
@@ -201,7 +203,7 @@ func doTest(t *testing.T, section string, input *inputType, count int) (good boo
 	eq := reflect.DeepEqual(gotResult, input.wantResult)
 
 	if !eq /*gotResult != input.wantResult*/ {
-		t.Errorf("%d: %q -> result = %v [%T], want = %v [%T]", count, input.source, gotResult, gotResult, input.wantResult, input.wantResult)
+		t.Errorf("%d: %q -> result = %v [%s], want = %v [%s]", count, input.source, gotResult, typeName(gotResult), input.wantResult, typeName(input.wantResult))
 		good = false
 	}
 

term.go

@@ -156,15 +156,15 @@ func (self *term) toInt(computedValue any, valueDescription string) (i int, err
 	if index64, ok := computedValue.(int64); ok {
 		i = int(index64)
 	} else {
-		err = self.Errorf("%s, got %T (%v)", valueDescription, computedValue, computedValue)
+		err = self.Errorf("%s, got %s (%v)", valueDescription, typeName(computedValue), computedValue)
 	}
 	return
 }
 
 func (self *term) errIncompatibleTypes(leftValue, rightValue any) error {
-	leftType := getTypeName(leftValue)
+	leftType := typeName(leftValue)
 	leftText := getFormatted(leftValue, Truncate)
-	rightType := getTypeName(rightValue)
+	rightType := typeName(rightValue)
 	rightText := getFormatted(rightValue, Truncate)
 	return self.tk.Errorf(
 		"left operand '%s' [%s] and right operand '%s' [%s] are not compatible with operator %q",
@@ -175,8 +175,8 @@ func (self *term) errIncompatibleTypes(leftValue, rightValue any) error {
 
 func (self *term) errIncompatibleType(value any) error {
 	return self.tk.Errorf(
-		"prefix/postfix operator %q do not support operand '%v' [%T]",
-		self.source(), value, value)
+		"prefix/postfix operator %q do not support operand '%v' [%s]",
+		self.source(), value, typeName(value))
 }
 
 func (self *term) Errorf(template string, args ...any) (err error) {

utils.go

@@ -204,8 +204,10 @@ func CloneFilteredMap[K comparable, V any](source map[K]V, filter func(key K) (a
 func toInt(value any, description string) (i int, err error) {
 	if valueInt64, ok := value.(int64); ok {
 		i = int(valueInt64)
+	} else if valueInt, ok := value.(int); ok {
+		i = valueInt
 	} else {
-		err = fmt.Errorf("%s expected integer, got %T (%v)", description, value, value)
+		err = fmt.Errorf("%s expected integer, got %s (%v)", description, typeName(value), value)
 	}
 	return
 }