term.go: replaced self receiver

Expr interface moved from ast.go to the new file expr.go

ast.go

@@ -8,11 +8,6 @@ import (
 	"strings"
 )
 
-type Expr interface {
-	Eval(ctx ExprContext) (result any, err error)
-	String() string
-}
-
 //-------- ast
 
 type ast struct {
@@ -24,65 +19,65 @@ func NewAst() *ast {
 	return &ast{}
 }
 
-func (self *ast) ToForest() {
-	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)
 		}
-		self.forest = append(self.forest, self.root)
-		self.root = nil
+		expr.forest = append(expr.forest, expr.root)
+		expr.root = nil
 	}
 }
 
-func (self *ast) String() string {
+func (expr *ast) String() string {
 	var sb strings.Builder
-	if self.root == nil {
+	if expr.root == nil {
 		sb.WriteString("(nil)")
 	} else {
-		self.root.toString(&sb)
+		expr.root.toString(&sb)
 	}
 	return sb.String()
 }
 
-func (self *ast) addTokens(tokens ...*Token) (err error) {
+func (expr *ast) addTokens(tokens ...*Token) (err error) {
 	for _, tk := range tokens {
-		if err = self.addToken(tk); err != nil {
+		if err = expr.addToken(tk); err != nil {
 			break
 		}
 	}
 	return
 }
 
-func (self *ast) addToken(tk *Token) (err error) {
-	_, err = self.addToken2(tk)
+func (expr *ast) addToken(tk *Token) (err error) {
+	_, err = expr.addToken2(tk)
 	return
 }
 
-func (self *ast) addToken2(tk *Token) (t *term, err error) {
+func (expr *ast) addToken2(tk *Token) (t *term, err error) {
 	if t = newTerm(tk); t != nil {
-		err = self.addTerm(t)
+		err = expr.addTerm(t)
 	} else {
 		err = tk.Errorf("unexpected token %q", tk.String())
 	}
 	return
 }
 
-func (self *ast) addTerm(node *term) (err error) {
-	if self.root == nil {
-		self.root = node
+func (expr *ast) addTerm(node *term) (err error) {
+	if expr.root == nil {
+		expr.root = node
 	} else {
-		self.root, err = self.insert(self.root, node)
+		expr.root, err = expr.insert(expr.root, node)
 	}
 	return
 }
 
-func (self *ast) insert(tree, node *term) (root *term, err error) {
+func (expr *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 = self.insert(last, node); err == nil {
+			if subRoot, err = expr.insert(last, node); err == nil {
 				subRoot.setParent(tree)
 			}
 		} else {
@@ -97,20 +92,20 @@ func (self *ast) insert(tree, node *term) (root *term, err error) {
 	return
 }
 
-func (self *ast) Finish() {
-	if self.root == nil && self.forest != nil && len(self.forest) >= 1 {
-		self.root = self.forest[len(self.forest)-1]
-		self.forest = self.forest[0 : len(self.forest)-1]
+func (expr *ast) Finish() {
+	if expr.root == nil && expr.forest != nil && len(expr.forest) >= 1 {
+		expr.root = expr.forest[len(expr.forest)-1]
+		expr.forest = expr.forest[0 : len(expr.forest)-1]
 	}
 }
 
-func (self *ast) Eval(ctx ExprContext) (result any, err error) {
-	self.Finish()
+func (expr *ast) Eval(ctx ExprContext) (result any, err error) {
+	expr.Finish()
 
-	if self.root != nil {
+	if expr.root != nil {
 		// initDefaultVars(ctx)
-		if self.forest != nil {
-			for _, root := range self.forest {
+		if expr.forest != nil {
+			for _, root := range expr.forest {
 				if result, err = root.compute(ctx); err == nil {
 					ctx.UnsafeSetVar(ControlLastResult, result)
 				} else {
@@ -120,7 +115,7 @@ func (self *ast) Eval(ctx ExprContext) (result any, err error) {
 			}
 		}
 		if err == nil {
-			if result, err = self.root.compute(ctx); err == nil {
+			if result, err = expr.root.compute(ctx); err == nil {
 				ctx.UnsafeSetVar(ControlLastResult, result)
 			}
 		}

builtin-base.go

@@ -180,9 +180,9 @@ func fractFunc(ctx ExprContext, name string, args []any) (result any, err error)
 	return
 }
 
-func iteratorFunc(ctx ExprContext, name string, args []any) (result any, err error) {
-	return
-}
+// func iteratorFunc(ctx ExprContext, name string, args []any) (result any, err error) {
+// 	return
+// }
 
 func ImportBuiltinsFuncs(ctx ExprContext) {
 	anyParams := []ExprFuncParam{

builtin-string.go

@@ -25,7 +25,7 @@ func doJoinStr(funcName string, sep string, it Iterator) (result any, err error)
 			return
 		}
 	}
-	if err == nil || err == io.EOF {
+	if err == io.EOF {
 		err = nil
 		result = sb.String()
 	}

byte-slider.go

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

expr-context.go

@@ -0,0 +1,23 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
+// expr-context.go
+package expr
+
+// ----Expression Context
+type ExprContext interface {
+	Clone() ExprContext
+	// Merge(ctx 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)
+	EnumFuncs(func(name string) (accept bool)) (funcNames []string)
+	GetFuncInfo(name string) (item ExprFunc, exists bool)
+	Call(name string, args []any) (result any, err error)
+	RegisterFuncInfo(info ExprFunc)
+	RegisterFunc(name string, f Functor, returnType string, param []ExprFuncParam) error
+}

expr-function.go

@@ -1,7 +1,7 @@
 // Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
 // All rights reserved.
 
-// context.go
+// expr-function.go
 package expr
 
 // ---- Functor interface
@@ -35,21 +35,3 @@ type ExprFunc interface {
 	PrepareCall(parentCtx ExprContext, name string, varParams *[]any) (ctx ExprContext, err error)
 	AllocContext(parentCtx ExprContext) (ctx ExprContext)
 }
-
-// ----Expression Context
-type ExprContext interface {
-	Clone() ExprContext
-	// Merge(ctx 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)
-	EnumFuncs(func(name string) (accept bool)) (funcNames []string)
-	GetFuncInfo(name string) (item ExprFunc, exists bool)
-	Call(name string, args []any) (result any, err error)
-	RegisterFuncInfo(info ExprFunc)
-	RegisterFunc(name string, f Functor, returnType string, param []ExprFuncParam) error
-}

expr.go

@@ -0,0 +1,11 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
+// expr.go
+package expr
+
+// ----Expression interface
+type Expr interface {
+	Eval(ctx ExprContext) (result any, err error)
+	String() string
+}

fraction-type.go

@@ -50,9 +50,10 @@ func makeGeneratingFraction(s string) (f *FractionType, err error) {
 	} else if s[0] == '+' {
 		s = s[1:]
 	}
-	if strings.HasSuffix(s, "()") {
-		s = s[0 : len(s)-2]
-	}
+//	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
@@ -311,7 +312,6 @@ func divAnyFract(af1, af2 any) (quot any, err error) {
 	if f2.num == 0 {
 		err = errors.New("division by zero")
 		return
-		return
 	}
 	if f1.num == 0 || f2.den == 0 {
 		quot = 0

function.go

@@ -112,25 +112,24 @@ type funcInfo struct {
 func newFuncInfo(name string, functor Functor, returnType string, params []ExprFuncParam) (info *funcInfo, err error) {
 	var minArgs = 0
 	var maxArgs = 0
-	if params != nil {
-		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
-			}
+	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,
 	}

import-utils.go

@@ -25,13 +25,13 @@ func checkStringParamExpected(funcName string, paramValue any, paramPos int) (er
 	return
 }
 
-func addSourceEnvImportDirs(varName string, dirList []string) []string {
-	return addEnvImportDirs(ENV_EXPR_SOURCE_PATH, dirList)
-}
+// 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 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 {

list-type.go

@@ -26,9 +26,10 @@ func newList(listAny []any) (list *ListType) {
 func NewList(listAny []any) (list *ListType) {
 	if listAny != nil {
 		ls := make(ListType, len(listAny))
-		for i, item := range listAny {
-			ls[i] = item
-		}
+//		for i, item := range listAny {
+//			ls[i] = item
+//		}
+		copy(ls, listAny)
 		list = &ls
 	}
 	return
@@ -105,16 +106,16 @@ 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 (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) {

operand-dict.go

@@ -18,8 +18,8 @@ func newDictTerm(args map[any]*term) *term {
 }
 
 // -------- dict func
-func evalDict(ctx ExprContext, self *term) (v any, err error) {
-	dict, _ := self.value().(map[any]*term)
+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

operand-expr.go

@@ -20,11 +20,11 @@ func newExprTerm(root *term) *term {
 }
 
 // -------- eval expr
-func evalExpr(ctx ExprContext, self *term) (v any, err error) {
-	if expr, ok := self.value().(*term); ok {
+func evalExpr(ctx ExprContext, opTerm *term) (v any, err error) {
+	if expr, ok := opTerm.value().(*term); ok {
 		v, err = expr.compute(ctx)
 	} else {
-		err = fmt.Errorf("expression expected, got %T", self.value())
+		err = fmt.Errorf("expression expected, got %T", opTerm.value())
 	}
 	return
 }

operand-func.go

@@ -21,10 +21,10 @@ func newFuncCallTerm(tk *Token, args []*term) *term {
 }
 
 // -------- eval func call
-func evalFuncCall(ctx ExprContext, self *term) (v any, err error) {
-	name, _ := self.tk.Value.(string)
-	params := make([]any, len(self.children), len(self.children)+5)
-	for i, tree := range self.children {
+func evalFuncCall(ctx ExprContext, opTerm *term) (v any, err error) {
+	name, _ := opTerm.tk.Value.(string)
+	params := make([]any, len(opTerm.children), len(opTerm.children)+5)
+	for i, tree := range opTerm.children {
 		var param any
 		if param, err = tree.compute(ctx); err != nil {
 			break
@@ -51,11 +51,11 @@ func newFuncDefTerm(tk *Token, args []*term) *term {
 }
 
 // -------- eval func def
-func evalFuncDef(ctx ExprContext, self *term) (v any, err error) {
-	bodySpec := self.value()
+func evalFuncDef(ctx ExprContext, opTerm *term) (v any, err error) {
+	bodySpec := opTerm.value()
 	if expr, ok := bodySpec.(*ast); ok {
-		paramList := make([]ExprFuncParam, 0, len(self.children))
-		for _, param := range self.children {
+		paramList := make([]ExprFuncParam, 0, len(opTerm.children))
+		for _, param := range opTerm.children {
 			var defValue any
 			flags := paramFlags(0)
 			if len(param.children) > 0 {

operand-iterator.go

@@ -5,28 +5,27 @@
 package expr
 
 import (
-	"fmt"
 	"slices"
 	"strings"
 )
 
 // -------- iterator term
 
-func newDsIteratorTerm(tk *Token, dsTerm *term, args []*term) *term {
-	tk.Sym = SymIterator
+// func newDsIteratorTerm(tk *Token, dsTerm *term, args []*term) *term {
+// 	tk.Sym = SymIterator
 
-	children := make([]*term, 0, 1+len(args))
-	children = append(children, dsTerm)
-	children = append(children, args...)
-	return &term{
-		tk:       *tk,
-		parent:   nil,
-		children: children,
-		position: posLeaf,
-		priority: priValue,
-		evalFunc: evalIterator,
-	}
-}
+// 	children := make([]*term, 0, 1+len(args))
+// 	children = append(children, dsTerm)
+// 	children = append(children, args...)
+// 	return &term{
+// 		tk:       *tk,
+// 		parent:   nil,
+// 		children: children,
+// 		position: posLeaf,
+// 		priority: priValue,
+// 		evalFunc: evalIterator,
+// 	}
+// }
 
 func newIteratorTerm(tk *Token, args []*term) *term {
 	tk.Sym = SymIterator
@@ -42,9 +41,9 @@ func newIteratorTerm(tk *Token, args []*term) *term {
 
 // -------- eval iterator
 
-func evalTermArray(ctx ExprContext, a []*term) (values []any, err error) {
-	values = make([]any, len(a))
-	for i, t := range a {
+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
@@ -55,18 +54,17 @@ func evalTermArray(ctx ExprContext, a []*term) (values []any, err error) {
 	return
 }
 
-func evalFirstChild(ctx ExprContext, self *term) (value any, err error) {
-	if len(self.children) < 1 || self.children[0] == nil {
-		err = self.Errorf("missing the data-source parameter")
+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 = self.children[0].compute(ctx)
+	value, err = iteratorTerm.children[0].compute(ctx)
 	return
 }
 
-func getDataSourceDict(ctx ExprContext, self *term, firstChildValue any) (ds map[string]Functor, err error) {
-	// if dictAny, ok := firstChildValue.(map[any]any); ok {
+func getDataSourceDict(iteratorTerm *term, firstChildValue any) (ds map[string]Functor, err error) {
 	if dictAny, ok := firstChildValue.(*DictType); ok {
 		requiredFields := []string{currentName, nextName}
 		fieldsMask := 0b11
@@ -74,7 +72,6 @@ func getDataSourceDict(ctx ExprContext, self *term, firstChildValue any) (ds map
 		ds = make(map[string]Functor)
 		for keyAny, item := range *dictAny {
 			if key, ok := keyAny.(string); ok {
-				//if functor, ok := item.(*funcDefFunctor); ok {
 				if functor, ok := item.(Functor); ok {
 					ds[key] = functor
 					if index := slices.Index(requiredFields, key); index >= 0 {
@@ -91,21 +88,22 @@ func getDataSourceDict(ctx ExprContext, self *term, firstChildValue any) (ds map
 					missingFields = append(missingFields, field)
 				}
 			}
-			err = fmt.Errorf("the data-source must provide a non-nil %q operator(s)", strings.Join(missingFields, ", "))
+//			err = fmt.Errorf("the data-source must provide a non-nil %q operator(s)", strings.Join(missingFields, ", "))
+			err = iteratorTerm.children[0].Errorf("the data-source must provide a non-nil %q operator(s)", strings.Join(missingFields, ", "))
 		}
 	}
 	return
 }
 
-func evalIterator(ctx ExprContext, self *term) (v any, err error) {
+func evalIterator(ctx ExprContext, opTerm *term) (v any, err error) {
 	var firstChildValue any
 	var ds map[string]Functor
 
-	if firstChildValue, err = evalFirstChild(ctx, self); err != nil {
+	if firstChildValue, err = evalFirstChild(ctx, opTerm); err != nil {
 		return
 	}
 
-	if ds, err = getDataSourceDict(ctx, self, firstChildValue); err != nil {
+	if ds, err = getDataSourceDict(opTerm, firstChildValue); err != nil {
 		return
 	}
 
@@ -113,8 +111,8 @@ func evalIterator(ctx ExprContext, self *term) (v any, err error) {
 		dc := newDataCursor(ctx, ds)
 		if initFunc, exists := ds[initName]; exists && initFunc != nil {
 			var args []any
-			if len(self.children) > 1 {
-				if args, err = evalTermArray(ctx, self.children[1:]); err != nil {
+			if len(opTerm.children) > 1 {
+				if args, err = evalTermArray(ctx, opTerm.children[1:]); err != nil {
 					return
 				}
 			} else {
@@ -128,20 +126,20 @@ func evalIterator(ctx ExprContext, self *term) (v any, err error) {
 			exportObjects(dc.ctx, initCtx)
 		}
 
-		dc.nextFunc, _ = ds[nextName]
-		dc.currentFunc, _ = ds[currentName]
-		dc.cleanFunc, _ = ds[cleanName]
-		dc.resetFunc, _ = ds[resetName]
+		dc.nextFunc = ds[nextName]
+		dc.currentFunc = ds[currentName]
+		dc.cleanFunc = ds[cleanName]
+		dc.resetFunc = ds[resetName]
 
 		v = dc
 	} else if list, ok := firstChildValue.(*ListType); ok {
 		var args []any
-		if args, err = evalSibling(ctx, self.children, nil); err == nil {
+		if args, err = evalSibling(ctx, opTerm.children, nil); err == nil {
 			v = NewListIterator(list, args)
 		}
 	} else {
 		var list []any
-		if list, err = evalSibling(ctx, self.children, firstChildValue); err == nil {
+		if list, err = evalSibling(ctx, opTerm.children, firstChildValue); err == nil {
 			v = NewArrayIterator(list)
 		}
 	}

operand-list.go

@@ -21,8 +21,8 @@ func newListTerm(row, col int, args []*term) *term {
 }
 
 // -------- list func
-func evalList(ctx ExprContext, self *term) (v any, err error) {
-	list, _ := self.value().([]*term)
+func evalList(ctx ExprContext, opTerm *term) (v any, err error) {
+	list, _ := opTerm.value().([]*term)
 	items := make(ListType, len(list))
 	for i, tree := range list {
 		var param any

operand-literal.go

@@ -17,8 +17,8 @@ func newLiteralTerm(tk *Token) *term {
 }
 
 // -------- eval func
-func evalLiteral(ctx ExprContext, self *term) (v any, err error) {
-	v = self.tk.Value
+func evalLiteral(ctx ExprContext, opTerm *term) (v any, err error) {
+	v = opTerm.tk.Value
 	return
 }
 

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, self *term) (v any, err error) {
+func evalSelectorCase(ctx ExprContext, opTerm *term) (v any, err error) {
 	var ok bool
-	if v, ok = self.value().(*selectorCase); !ok {
-		err = fmt.Errorf("selector-case expected, got %T", self.value())
+	if v, ok = opTerm.value().(*selectorCase); !ok {
+		err = fmt.Errorf("selector-case expected, got %T", opTerm.value())
 	}
 	return
 }

operand-var.go

@@ -21,9 +21,9 @@ func newVarTerm(tk *Token) *term {
 }
 
 // -------- eval func
-func evalVar(ctx ExprContext, self *term) (v any, err error) {
+func evalVar(ctx ExprContext, opTerm *term) (v any, err error) {
 	var exists bool
-	name := self.source()
+	name := opTerm.source()
 	if v, exists = GetVar(ctx, name); !exists {
 		if info, exists, _ := GetFuncInfo(ctx, name); exists {
 			v = info.Functor()

operator-assign.go

@@ -60,19 +60,19 @@ func assignValue(ctx ExprContext, leftTerm *term, v any) (err error) {
 	return
 }
 
-func evalAssign(ctx ExprContext, self *term) (v any, err error) {
-	if err = self.checkOperands(); err != nil {
+func evalAssign(ctx ExprContext, opTerm *term) (v any, err error) {
+	if err = opTerm.checkOperands(); err != nil {
 		return
 	}
 
-	leftTerm := self.children[0]
+	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", self.tk.source)
+		err = leftTerm.tk.Errorf("left operand of %q must be a variable or a collection's item", opTerm.tk.source)
 		return
 	}
 
-	rightChild := self.children[1]
+	rightChild := opTerm.children[1]
 
 	if v, err = rightChild.compute(ctx); err == nil {
 		if functor, ok := v.(Functor); ok {
@@ -83,7 +83,7 @@ func evalAssign(ctx ExprContext, self *term) (v any, err error) {
 
 				ctx.RegisterFunc(leftTerm.source(), functor, TypeAny, paramSpecs)
 			} else {
-				err = self.Errorf("unknown function %s()", rightChild.source())
+				err = opTerm.Errorf("unknown function %s()", rightChild.source())
 			}
 		} else {
 			err = assignValue(ctx, leftTerm, v)

operator-bool.go

@@ -18,17 +18,17 @@ func newNotTerm(tk *Token) (inst *term) {
 	}
 }
 
-func evalNot(ctx ExprContext, self *term) (v any, err error) {
+func evalNot(ctx ExprContext, opTerm *term) (v any, err error) {
 	var rightValue any
 
-	if rightValue, err = self.evalPrefix(ctx); err != nil {
+	if rightValue, err = opTerm.evalPrefix(ctx); err != nil {
 		return
 	}
 
 	if b, ok := ToBool(rightValue); ok {
 		v = !b
 	} else {
-		err = self.errIncompatibleType(rightValue)
+		err = opTerm.errIncompatibleType(rightValue)
 	}
 	return
 }

operator-builtin.go

@@ -18,10 +18,10 @@ func newBuiltinTerm(tk *Token) (inst *term) {
 	}
 }
 
-func evalBuiltin(ctx ExprContext, self *term) (v any, err error) {
+func evalBuiltin(ctx ExprContext, opTerm *term) (v any, err error) {
 	var childValue any
 
-	if childValue, err = self.evalPrefix(ctx); err != nil {
+	if childValue, err = opTerm.evalPrefix(ctx); err != nil {
 		return
 	}
 
@@ -37,11 +37,11 @@ func evalBuiltin(ctx ExprContext, self *term) (v any, err error) {
 				if ImportInContext(module) {
 					count++
 				} else {
-					err = self.Errorf("unknown builtin module %q", module)
+					err = opTerm.Errorf("unknown builtin module %q", module)
 					break
 				}
 			} else {
-				err = self.Errorf("expected string at item nr %d, got %s", it.Index()+1, TypeName(moduleSpec))
+				err = opTerm.Errorf("expected string at item nr %d, got %s", it.Index()+1, TypeName(moduleSpec))
 				break
 			}
 		}

operator-but.go

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

operator-context.go

@@ -16,15 +16,15 @@ func newContextTerm(tk *Token) (inst *term) {
 	}
 }
 
-func evalContextValue(ctx ExprContext, self *term) (v any, err error) {
+func evalContextValue(ctx ExprContext, opTerm *term) (v any, err error) {
 	var childValue any
 
 	var sourceCtx ExprContext
-	if self.children == nil || len(self.children) == 0 {
+	if opTerm.children == nil || len(opTerm.children) == 0 {
 		sourceCtx = ctx
-	} else if self.children[0].symbol() == SymVariable && self.children[0].source() == "global" {
+	} else if opTerm.children[0].symbol() == SymVariable && opTerm.children[0].source() == "global" {
 		sourceCtx = globalCtx
-	} else if childValue, err = self.evalPrefix(ctx); err == nil {
+	} else if childValue, err = opTerm.evalPrefix(ctx); err == nil {
 		if dc, ok := childValue.(*dataCursor); ok {
 			sourceCtx = dc.ctx
 		}
@@ -49,7 +49,7 @@ func evalContextValue(ctx ExprContext, self *term) (v any, err error) {
 			v = d
 		}
 	} else {
-		err = self.errIncompatibleType(childValue)
+		err = opTerm.errIncompatibleType(childValue)
 	}
 	return
 }

operator-ctrl.go

@@ -16,7 +16,7 @@ func newExportAllTerm(tk *Token) (inst *term) {
 	}
 }
 
-func evalExportAll(ctx ExprContext, self *term) (v any, err error) {
+func evalExportAll(ctx ExprContext, opTerm *term) (v any, err error) {
 	CtrlEnable(ctx, control_export_all)
 	return
 }

operator-default.go

@@ -16,23 +16,23 @@ func newDefaultTerm(tk *Token) (inst *term) {
 	}
 }
 
-func evalDefault(ctx ExprContext, self *term) (v any, err error) {
+func evalDefault(ctx ExprContext, opTerm *term) (v any, err error) {
 	var rightValue any
 
-	if err = self.checkOperands(); err != nil {
+	if err = opTerm.checkOperands(); err != nil {
 		return
 	}
 
-	leftTerm := self.children[0]
+	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, self)
+		err = ErrLeftOperandMustBeVariable(leftTerm, opTerm)
 		return
 	}
 
 	if leftValue, exists := ctx.GetVar(leftTerm.source()); exists {
 		v = leftValue
-	} else if rightValue, err = self.children[1].compute(ctx); err == nil {
+	} else if rightValue, err = opTerm.children[1].compute(ctx); err == nil {
 		v = rightValue
 	}
 	return
@@ -50,22 +50,22 @@ func newAlternateTerm(tk *Token) (inst *term) {
 	}
 }
 
-func evalAlternate(ctx ExprContext, self *term) (v any, err error) {
+func evalAlternate(ctx ExprContext, opTerm *term) (v any, err error) {
 	var rightValue any
 
-	if err = self.checkOperands(); err != nil {
+	if err = opTerm.checkOperands(); err != nil {
 		return
 	}
 
-	leftTerm := self.children[0]
+	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, self)
+		err = ErrLeftOperandMustBeVariable(leftTerm, opTerm)
 		return
 	}
 
 	if leftValue, exists := ctx.GetVar(leftTerm.source()); exists && leftValue != nil {
-		if rightValue, err = self.children[1].compute(ctx); err == nil {
+		if rightValue, err = opTerm.children[1].compute(ctx); err == nil {
 			v = rightValue
 		}
 	} else {
@@ -86,23 +86,23 @@ func newDefaultAssignTerm(tk *Token) (inst *term) {
 	}
 }
 
-func evalAssignDefault(ctx ExprContext, self *term) (v any, err error) {
+func evalAssignDefault(ctx ExprContext, opTerm *term) (v any, err error) {
 	var rightValue any
 
-	if err = self.checkOperands(); err != nil {
+	if err = opTerm.checkOperands(); err != nil {
 		return
 	}
 
-	leftTerm := self.children[0]
+	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, self)
+		err = ErrLeftOperandMustBeVariable(leftTerm, opTerm)
 		return
 	}
 
 	if leftValue, exists := ctx.GetVar(leftTerm.source()); exists {
 		v = leftValue
-	} else if rightValue, err = self.children[1].compute(ctx); err == nil {
+	} 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{

operator-dot.go

@@ -15,17 +15,17 @@ func newDotTerm(tk *Token) (inst *term) {
 	}
 }
 
-func evalDot(ctx ExprContext, self *term) (v any, err error) {
+func evalDot(ctx ExprContext, opTerm *term) (v any, err error) {
 	var leftValue, rightValue any
 
-	if err = self.checkOperands(); err != nil {
+	if err = opTerm.checkOperands(); err != nil {
 		return
 	}
-	if leftValue, err = self.children[0].compute(ctx); err != nil {
+	if leftValue, err = opTerm.children[0].compute(ctx); err != nil {
 		return
 	}
 
-	indexTerm := self.children[1]
+	indexTerm := opTerm.children[1]
 
 	switch unboxedValue := leftValue.(type) {
 	case ExtIterator:
@@ -41,8 +41,8 @@ func evalDot(ctx ExprContext, self *term) (v any, err error) {
 			err = indexTerm.tk.ErrorExpectedGot("identifier")
 		}
 	default:
-		if rightValue, err = self.children[1].compute(ctx); err == nil {
-			err = self.errIncompatibleTypes(leftValue, rightValue)
+		if rightValue, err = opTerm.children[1].compute(ctx); err == nil {
+			err = opTerm.errIncompatibleTypes(leftValue, rightValue)
 		}
 	}
 	return

operator-fact.go

@@ -18,10 +18,10 @@ func newFactTerm(tk *Token) (inst *term) {
 	}
 }
 
-func evalFact(ctx ExprContext, self *term) (v any, err error) {
+func evalFact(ctx ExprContext, opTerm *term) (v any, err error) {
 	var leftValue any
 
-	if leftValue, err = self.evalPrefix(ctx); err != nil {
+	if leftValue, err = opTerm.evalPrefix(ctx); err != nil {
 		return
 	}
 
@@ -36,7 +36,7 @@ func evalFact(ctx ExprContext, self *term) (v any, err error) {
 			err = fmt.Errorf("factorial of a negative integer (%d) is not allowed", i)
 		}
 	} else {
-		err = self.errIncompatibleType(leftValue)
+		err = opTerm.errIncompatibleType(leftValue)
 	}
 	return
 }

operator-fraction.go

@@ -24,12 +24,12 @@ func newFractionTerm(tk *Token) *term {
 }
 
 // -------- eval func
-func evalFraction(ctx ExprContext, self *term) (v any, err error) {
+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 = self.evalInfix(ctx); err != nil {
+	if numValue, denValue, err = opTerm.evalInfix(ctx); err != nil {
 		return
 	}
 	if num, ok = numValue.(int64); !ok {

operator-in.go

@@ -21,10 +21,10 @@ func newInTerm(tk *Token) (inst *term) {
 // 	return
 // }
 
-func evalIn(ctx ExprContext, self *term) (v any, err error) {
+func evalIn(ctx ExprContext, opTerm *term) (v any, err error) {
 	var leftValue, rightValue any
 
-	if leftValue, rightValue, err = self.evalInfix(ctx); err != nil {
+	if leftValue, rightValue, err = opTerm.evalInfix(ctx); err != nil {
 		return
 	}
 
@@ -35,7 +35,7 @@ func evalIn(ctx ExprContext, self *term) (v any, err error) {
 		dict, _ := rightValue.(*DictType)
 		v = dict.hasKey(leftValue)
 	} else {
-		err = self.errIncompatibleTypes(leftValue, rightValue)
+		err = opTerm.errIncompatibleTypes(leftValue, rightValue)
 	}
 	return
 }

operator-include.go

@@ -16,10 +16,10 @@ func newIncludeTerm(tk *Token) (inst *term) {
 	}
 }
 
-func evalInclude(ctx ExprContext, self *term) (v any, err error) {
+func evalInclude(ctx ExprContext, opTerm *term) (v any, err error) {
 	var childValue any
 
-	if childValue, err = self.evalPrefix(ctx); err != nil {
+	if childValue, err = opTerm.evalPrefix(ctx); err != nil {
 		return
 	}
 
@@ -31,11 +31,11 @@ func evalInclude(ctx ExprContext, self *term) (v any, err error) {
 				if v, err = EvalFile(ctx, filePath); err == nil {
 					count++
 				} else {
-					err = self.Errorf("can't load file %q", filePath)
+					err = opTerm.Errorf("can't load file %q", filePath)
 					break
 				}
 			} else {
-				err = self.Errorf("expected string at item nr %d, got %T", i+1, filePathSpec)
+				err = opTerm.Errorf("expected string at item nr %d, got %T", i+1, filePathSpec)
 				break
 			}
 		}
@@ -45,7 +45,7 @@ func evalInclude(ctx ExprContext, self *term) (v any, err error) {
 			count++
 		}
 	} else {
-		err = self.errIncompatibleType(childValue)
+		err = opTerm.errIncompatibleType(childValue)
 	}
 	if err == nil {
 		v = count

operator-index.go

@@ -15,7 +15,7 @@ func newIndexTerm(tk *Token) (inst *term) {
 	}
 }
 
-func verifyKey(indexTerm *term, indexList *ListType) (index any, err error) {
+func verifyKey(indexList *ListType) (index any, err error) {
 	index = (*indexList)[0]
 	return
 }
@@ -59,18 +59,18 @@ func verifyRange(indexTerm *term, indexList *ListType, maxValue int) (startIndex
 	return
 }
 
-func evalIndex(ctx ExprContext, self *term) (v any, err error) {
+func evalIndex(ctx ExprContext, opTerm *term) (v any, err error) {
 	var leftValue, rightValue any
 	var indexList *ListType
 	var ok bool
 
-	if leftValue, rightValue, err = self.evalInfix(ctx); err != nil {
+	if leftValue, rightValue, err = opTerm.evalInfix(ctx); err != nil {
 		return
 	}
 
-	indexTerm := self.children[1]
+	indexTerm := opTerm.children[1]
 	if indexList, ok = rightValue.(*ListType); !ok {
-		err = self.Errorf("invalid index expression")
+		err = opTerm.Errorf("invalid index expression")
 		return
 	} else if len(*indexList) != 1 {
 		err = indexTerm.Errorf("one index only is allowed")
@@ -90,16 +90,9 @@ func evalIndex(ctx ExprContext, self *term) (v any, err error) {
 				v = string(unboxedValue[index])
 			}
 		case *DictType:
-/* 			var ok bool
-			var indexValue any
-			if indexValue, err = verifyKey(indexTerm, indexList); err == nil {
-				if v, ok = (*unboxedValue)[indexValue]; !ok {
-					err = indexTerm.Errorf("key %v does not belong to the dictionary", rightValue)
-				}
-			} */
 			v, err = getDictItem(unboxedValue, indexTerm, indexList, rightValue)
 		default:
-			err = self.errIncompatibleTypes(leftValue, rightValue)
+			err = opTerm.errIncompatibleTypes(leftValue, rightValue)
 		}
 	} else if isIntPair((*indexList)[0]) {
 		switch unboxedValue := leftValue.(type) {
@@ -115,18 +108,10 @@ func evalIndex(ctx ExprContext, self *term) (v any, err error) {
 				v = unboxedValue[start:end]
 			}
 		default:
-			err = self.errIncompatibleTypes(leftValue, rightValue)
+			err = opTerm.errIncompatibleTypes(leftValue, rightValue)
 		}
 	} else if IsDict(leftValue) {
 		d := leftValue.(*DictType)
-
-		/* 		var ok bool
-		   		var indexValue any
-		   		if indexValue, err = verifyKey(indexTerm, indexList); err == nil {
-		   			if v, ok = (*d)[indexValue]; !ok {
-		   				err = indexTerm.Errorf("key %v does not belong to the dictionary", rightValue)
-		   			}
-		   		}*/
 		v, err = getDictItem(d, indexTerm, indexList, rightValue)
 	}
 	return
@@ -136,7 +121,7 @@ func getDictItem(d *DictType, indexTerm *term, indexList *ListType, rightValue a
 	var ok bool
 	var indexValue any
 
-	if indexValue, err = verifyKey(indexTerm, indexList); err == nil {
+	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)
 		}

operator-insert.go

@@ -26,10 +26,10 @@ func newAppendTerm(tk *Token) (inst *term) {
 	}
 }
 
-func evalInsert(ctx ExprContext, self *term) (v any, err error) {
+func evalInsert(ctx ExprContext, opTerm *term) (v any, err error) {
 	var leftValue, rightValue any
 
-	if leftValue, rightValue, err = self.evalInfix(ctx); err != nil {
+	if leftValue, rightValue, err = opTerm.evalInfix(ctx); err != nil {
 		return
 	}
 
@@ -37,19 +37,19 @@ func evalInsert(ctx ExprContext, self *term) (v any, err error) {
 		list, _ := rightValue.(*ListType)
 		newList := append(ListType{leftValue}, *list...)
 		v = &newList
-		if self.children[1].symbol() == SymVariable {
-			ctx.UnsafeSetVar(self.children[1].source(), v)
+		if opTerm.children[1].symbol() == SymVariable {
+			ctx.UnsafeSetVar(opTerm.children[1].source(), v)
 		}
 	} else {
-		err = self.errIncompatibleTypes(leftValue, rightValue)
+		err = opTerm.errIncompatibleTypes(leftValue, rightValue)
 	}
 	return
 }
 
-func evalAppend(ctx ExprContext, self *term) (v any, err error) {
+func evalAppend(ctx ExprContext, opTerm *term) (v any, err error) {
 	var leftValue, rightValue any
 
-	if leftValue, rightValue, err = self.evalInfix(ctx); err != nil {
+	if leftValue, rightValue, err = opTerm.evalInfix(ctx); err != nil {
 		return
 	}
 
@@ -57,11 +57,11 @@ func evalAppend(ctx ExprContext, self *term) (v any, err error) {
 		list, _ := leftValue.(*ListType)
 		newList := append(*list, rightValue)
 		v = &newList
-		if self.children[0].symbol() == SymVariable {
-			ctx.UnsafeSetVar(self.children[0].source(), v)
+		if opTerm.children[0].symbol() == SymVariable {
+			ctx.UnsafeSetVar(opTerm.children[0].source(), v)
 		}
 	} else {
-		err = self.errIncompatibleTypes(leftValue, rightValue)
+		err = opTerm.errIncompatibleTypes(leftValue, rightValue)
 	}
 	return
 }

operator-iter-value.go

@@ -16,17 +16,17 @@ func newIterValueTerm(tk *Token) (inst *term) {
 	}
 }
 
-func evalIterValue(ctx ExprContext, self *term) (v any, err error) {
+func evalIterValue(ctx ExprContext, opTerm *term) (v any, err error) {
 	var childValue any
 
-	if childValue, err = self.evalPrefix(ctx); err != nil {
+	if childValue, err = opTerm.evalPrefix(ctx); err != nil {
 		return
 	}
 
 	if it, ok := childValue.(Iterator); ok {
 		v, err = it.Current()
 	} else {
-		err = self.errIncompatibleType(childValue)
+		err = opTerm.errIncompatibleType(childValue)
 	}
 	return
 }

operator-length.go

@@ -16,10 +16,10 @@ func newLengthTerm(tk *Token) (inst *term) {
 	}
 }
 
-func evalLength(ctx ExprContext, self *term) (v any, err error) {
+func evalLength(ctx ExprContext, opTerm *term) (v any, err error) {
 	var childValue any
 
-	if childValue, err = self.evalPrefix(ctx); err != nil {
+	if childValue, err = opTerm.evalPrefix(ctx); err != nil {
 		return
 	}
 
@@ -41,7 +41,7 @@ func evalLength(ctx ExprContext, self *term) (v any, err error) {
 			v = int64(it.Index() + 1)
 		}
 	} else {
-		err = self.errIncompatibleType(childValue)
+		err = opTerm.errIncompatibleType(childValue)
 	}
 	return
 }

operator-plugin.go

@@ -20,11 +20,11 @@ func newPluginTerm(tk *Token) (inst *term) {
 	}
 }
 
-func evalPlugin(ctx ExprContext, self *term) (v any, err error) {
+func evalPlugin(ctx ExprContext, opTerm *term) (v any, err error) {
 	var childValue any
 	var moduleSpec any
 
-	if childValue, err = self.evalPrefix(ctx); err != nil {
+	if childValue, err = opTerm.evalPrefix(ctx); err != nil {
 		return
 	}
 
@@ -38,7 +38,7 @@ func evalPlugin(ctx ExprContext, self *term) (v any, err error) {
 			}
 			count++
 		} else {
-			err = self.Errorf("expected string as item nr %d, got %s", it.Index()+1, TypeName(moduleSpec))
+			err = opTerm.Errorf("expected string as item nr %d, got %s", it.Index()+1, TypeName(moduleSpec))
 			break
 		}
 	}

operator-post-inc.go

@@ -17,20 +17,20 @@ func newPostIncTerm(tk *Token) *term {
 	}
 }
 
-func evalPostInc(ctx ExprContext, self *term) (v any, err error) {
+func evalPostInc(ctx ExprContext, opTerm *term) (v any, err error) {
 	var childValue any
-	if childValue, err = self.evalPrefix(ctx); err != nil {
+	if childValue, err = opTerm.evalPrefix(ctx); err != nil {
 		return
 	}
 
 	if it, ok := childValue.(Iterator); ok {
 		v, err = it.Next()
-	} else if IsInteger(childValue) && self.children[0].symbol() == SymVariable {
+	} else if IsInteger(childValue) && opTerm.children[0].symbol() == SymVariable {
 		v = childValue
 		i, _ := childValue.(int64)
-		ctx.SetVar(self.children[0].source(), i+1)
+		ctx.SetVar(opTerm.children[0].source(), i+1)
 	} else {
-		err = self.errIncompatibleType(childValue)
+		err = opTerm.errIncompatibleType(childValue)
 	}
 	return
 }

operator-prod.go

@@ -14,8 +14,6 @@ import (
 func newMultiplyTerm(tk *Token) (inst *term) {
 	return &term{
 		tk: *tk,
-		// class:    classOperator,
-		// kind:     kindUnknown,
 		children: make([]*term, 0, 2),
 		position: posInfix,
 		priority: priProduct,
@@ -23,10 +21,10 @@ func newMultiplyTerm(tk *Token) (inst *term) {
 	}
 }
 
-func evalMultiply(ctx ExprContext, self *term) (v any, err error) {
+func evalMultiply(ctx ExprContext, prodTerm *term) (v any, err error) {
 	var leftValue, rightValue any
 
-	if leftValue, rightValue, err = self.evalInfix(ctx); err != nil {
+	if leftValue, rightValue, err = prodTerm.evalInfix(ctx); err != nil {
 		return
 	}
 
@@ -45,7 +43,7 @@ func evalMultiply(ctx ExprContext, self *term) (v any, err error) {
 			v = leftInt * rightInt
 		}
 	} else {
-		err = self.errIncompatibleTypes(leftValue, rightValue)
+		err = prodTerm.errIncompatibleTypes(leftValue, rightValue)
 	}
 	return
 }
@@ -55,8 +53,6 @@ func evalMultiply(ctx ExprContext, self *term) (v any, err error) {
 func newDivideTerm(tk *Token) (inst *term) {
 	return &term{
 		tk: *tk,
-		// class:    classOperator,
-		// kind:     kindUnknown,
 		children: make([]*term, 0, 2),
 		position: posInfix,
 		priority: priProduct,
@@ -64,10 +60,10 @@ func newDivideTerm(tk *Token) (inst *term) {
 	}
 }
 
-func evalDivide(ctx ExprContext, self *term) (v any, err error) {
+func evalDivide(ctx ExprContext, opTerm *term) (v any, err error) {
 	var leftValue, rightValue any
 
-	if leftValue, rightValue, err = self.evalInfix(ctx); err != nil {
+	if leftValue, rightValue, err = opTerm.evalInfix(ctx); err != nil {
 		return
 	}
 
@@ -90,7 +86,7 @@ func evalDivide(ctx ExprContext, self *term) (v any, err error) {
 			}
 		}
 	} else {
-		err = self.errIncompatibleTypes(leftValue, rightValue)
+		err = opTerm.errIncompatibleTypes(leftValue, rightValue)
 	}
 	return
 }
@@ -107,10 +103,10 @@ func newDivideAsFloatTerm(tk *Token) (inst *term) {
 	}
 }
 
-func evalDivideAsFloat(ctx ExprContext, self *term) (v any, err error) {
+func evalDivideAsFloat(ctx ExprContext, floatDivTerm *term) (v any, err error) {
 	var leftValue, rightValue any
 
-	if leftValue, rightValue, err = self.evalInfix(ctx); err != nil {
+	if leftValue, rightValue, err = floatDivTerm.evalInfix(ctx); err != nil {
 		return
 	}
 
@@ -122,18 +118,16 @@ func evalDivideAsFloat(ctx ExprContext, self *term) (v any, err error) {
 			v = numAsFloat(leftValue) / d
 		}
 	} else {
-		err = self.errIncompatibleTypes(leftValue, rightValue)
+		err = floatDivTerm.errIncompatibleTypes(leftValue, rightValue)
 	}
 	return
 }
 
 //-------- reminder term
 
-func newReminderTerm(tk *Token) (inst *term) {
+func newRemainderTerm(tk *Token) (inst *term) {
 	return &term{
 		tk: *tk,
-		// class:    classOperator,
-		// kind:     kindUnknown,
 		children: make([]*term, 0, 2),
 		position: posInfix,
 		priority: priProduct,
@@ -141,10 +135,10 @@ func newReminderTerm(tk *Token) (inst *term) {
 	}
 }
 
-func evalReminder(ctx ExprContext, self *term) (v any, err error) {
+func evalReminder(ctx ExprContext, ramainderTerm *term) (v any, err error) {
 	var leftValue, rightValue any
 
-	if leftValue, rightValue, err = self.evalInfix(ctx); err != nil {
+	if leftValue, rightValue, err = ramainderTerm.evalInfix(ctx); err != nil {
 		return
 	}
 
@@ -157,7 +151,7 @@ func evalReminder(ctx ExprContext, self *term) (v any, err error) {
 			v = leftInt % rightInt
 		}
 	} else {
-		err = self.errIncompatibleTypes(leftValue, rightValue)
+		err = ramainderTerm.errIncompatibleTypes(leftValue, rightValue)
 	}
 	return
 }
@@ -167,5 +161,5 @@ func init() {
 	registerTermConstructor(SymStar, newMultiplyTerm)
 	registerTermConstructor(SymSlash, newDivideTerm)
 	registerTermConstructor(SymDotSlash, newDivideAsFloatTerm)
-	registerTermConstructor(SymPercent, newReminderTerm)
+	registerTermConstructor(SymPercent, newRemainderTerm)
 }

operator-range.go

@@ -34,25 +34,25 @@ func newRangeTerm(tk *Token) (inst *term) {
 	}
 }
 
-func evalRange(ctx ExprContext, self *term) (v any, err error) {
+func evalRange(ctx ExprContext, opTerm *term) (v any, err error) {
 	var leftValue, rightValue any
 
 	// if err = self.checkOperands(); err != nil {
 	// 	return
 	// }
-	if len(self.children) == 0 {
+	if len(opTerm.children) == 0 {
 		leftValue = int64(0)
 		rightValue = int64(-1)
-	} else if len(self.children) == 1 {
-		if leftValue, err = self.children[0].compute(ctx); err != nil {
+	} 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 = self.evalInfix(ctx); err != nil {
+	} else if leftValue, rightValue, err = opTerm.evalInfix(ctx); err != nil {
 		return
 	}
 	if !(IsInteger(leftValue) && IsInteger(rightValue)) {
-		err = self.errIncompatibleTypes(leftValue, rightValue)
+		err = opTerm.errIncompatibleTypes(leftValue, rightValue)
 		return
 	}
 

operator-rel.go

@@ -45,10 +45,10 @@ func equals(a, b any, deepCmp deepFuncTemplate) (eq bool, err error) {
 	return
 }
 
-func evalEqual(ctx ExprContext, self *term) (v any, err error) {
+func evalEqual(ctx ExprContext, opTerm *term) (v any, err error) {
 	var leftValue, rightValue any
 
-	if leftValue, rightValue, err = self.evalInfix(ctx); err != nil {
+	if leftValue, rightValue, err = opTerm.evalInfix(ctx); err != nil {
 		return
 	}
 
@@ -68,8 +68,8 @@ func newNotEqualTerm(tk *Token) (inst *term) {
 	}
 }
 
-func evalNotEqual(ctx ExprContext, self *term) (v any, err error) {
-	if v, err = evalEqual(ctx, self); err == nil {
+func evalNotEqual(ctx ExprContext, opTerm *term) (v any, err error) {
+	if v, err = evalEqual(ctx, opTerm); err == nil {
 		b, _ := ToBool(v)
 		v = !b
 	}
@@ -119,13 +119,13 @@ func lessThan(self *term, a, b any) (isLess bool, err error) {
 	return
 }
 
-func evalLess(ctx ExprContext, self *term) (v any, err error) {
+func evalLess(ctx ExprContext, opTerm *term) (v any, err error) {
 	var leftValue, rightValue any
 
-	if leftValue, rightValue, err = self.evalInfix(ctx); err != nil {
+	if leftValue, rightValue, err = opTerm.evalInfix(ctx); err != nil {
 		return
 	}
-	v, err = lessThan(self, leftValue, rightValue)
+	v, err = lessThan(opTerm, leftValue, rightValue)
 	return
 }
 
@@ -154,14 +154,14 @@ func lessThanOrEqual(self *term, a, b any) (isLessEq bool, err error) {
 	return
 }
 
-func evalLessEqual(ctx ExprContext, self *term) (v any, err error) {
+func evalLessEqual(ctx ExprContext, opTerm *term) (v any, err error) {
 	var leftValue, rightValue any
 
-	if leftValue, rightValue, err = self.evalInfix(ctx); err != nil {
+	if leftValue, rightValue, err = opTerm.evalInfix(ctx); err != nil {
 		return
 	}
 
-	v, err = lessThanOrEqual(self, leftValue, rightValue)
+	v, err = lessThanOrEqual(opTerm, leftValue, rightValue)
 
 	return
 }
@@ -178,14 +178,14 @@ func newGreaterTerm(tk *Token) (inst *term) {
 	}
 }
 
-func evalGreater(ctx ExprContext, self *term) (v any, err error) {
+func evalGreater(ctx ExprContext, opTerm *term) (v any, err error) {
 	var leftValue, rightValue any
 
-	if leftValue, rightValue, err = self.evalInfix(ctx); err != nil {
+	if leftValue, rightValue, err = opTerm.evalInfix(ctx); err != nil {
 		return
 	}
 
-	v, err = lessThan(self, rightValue, leftValue)
+	v, err = lessThan(opTerm, rightValue, leftValue)
 	return
 }
 
@@ -201,14 +201,14 @@ func newGreaterEqualTerm(tk *Token) (inst *term) {
 	}
 }
 
-func evalGreaterEqual(ctx ExprContext, self *term) (v any, err error) {
+func evalGreaterEqual(ctx ExprContext, opTerm *term) (v any, err error) {
 	var leftValue, rightValue any
 
-	if leftValue, rightValue, err = self.evalInfix(ctx); err != nil {
+	if leftValue, rightValue, err = opTerm.evalInfix(ctx); err != nil {
 		return
 	}
 
-	v, err = lessThanOrEqual(self, rightValue, leftValue)
+	v, err = lessThanOrEqual(opTerm, rightValue, leftValue)
 	return
 }
 

operator-selector.go

@@ -39,19 +39,19 @@ func trySelectorCase(ctx ExprContext, exprValue, caseSel any, caseIndex int) (ma
 	return
 }
 
-func evalSelector(ctx ExprContext, self *term) (v any, err error) {
+func evalSelector(ctx ExprContext, opTerm *term) (v any, err error) {
 	var exprValue any
 	var match bool
 
-	if err = self.checkOperands(); err != nil {
+	if err = opTerm.checkOperands(); err != nil {
 		return
 	}
-	exprTerm := self.children[0]
+	exprTerm := opTerm.children[0]
 	if exprValue, err = exprTerm.compute(ctx); err != nil {
 		return
 	}
 
-	caseListTerm := self.children[1]
+	caseListTerm := opTerm.children[1]
 	caseList, _ := caseListTerm.value().([]*term)
 	for i, caseTerm := range caseList {
 		caseSel := caseTerm.value()

operator-sign.go

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

operator-sum.go

@@ -21,10 +21,10 @@ func newPlusTerm(tk *Token) (inst *term) {
 	}
 }
 
-func evalPlus(ctx ExprContext, self *term) (v any, err error) {
+func evalPlus(ctx ExprContext, plusTerm *term) (v any, err error) {
 	var leftValue, rightValue any
 
-	if leftValue, rightValue, err = self.evalInfix(ctx); err != nil {
+	if leftValue, rightValue, err = plusTerm.evalInfix(ctx); err != nil {
 		return
 	}
 
@@ -44,12 +44,8 @@ func evalPlus(ctx ExprContext, self *term) (v any, err error) {
 		rightList, _ = rightValue.(*ListType)
 
 		sumList := make(ListType, 0, len(*leftList)+len(*rightList))
-		for _, item := range *leftList {
-			sumList = append(sumList, item)
-		}
-		for _, item := range *rightList {
-			sumList = append(sumList, item)
-		}
+		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) {
@@ -64,7 +60,7 @@ func evalPlus(ctx ExprContext, self *term) (v any, err error) {
 		c.merge(rightDict)
 		v = c
 	} else {
-		err = self.errIncompatibleTypes(leftValue, rightValue)
+		err = plusTerm.errIncompatibleTypes(leftValue, rightValue)
 	}
 	return
 }
@@ -81,10 +77,10 @@ func newMinusTerm(tk *Token) (inst *term) {
 	}
 }
 
-func evalMinus(ctx ExprContext, self *term) (v any, err error) {
+func evalMinus(ctx ExprContext, minusTerm *term) (v any, err error) {
 	var leftValue, rightValue any
 
-	if leftValue, rightValue, err = self.evalInfix(ctx); err != nil {
+	if leftValue, rightValue, err = minusTerm.evalInfix(ctx); err != nil {
 		return
 	}
 
@@ -109,7 +105,7 @@ func evalMinus(ctx ExprContext, self *term) (v any, err error) {
 		}
 		v = &diffList
 	} else {
-		err = self.errIncompatibleTypes(leftValue, rightValue)
+		err = minusTerm.errIncompatibleTypes(leftValue, rightValue)
 	}
 	return
 }

parser.go

@@ -18,13 +18,13 @@ func NewParser() (p *parser) {
 	return p
 }
 
-func (self *parser) parseFuncCall(scanner *scanner, allowVarRef bool, tk *Token) (tree *term, err error) {
+func (parser *parser) parseFuncCall(scanner *scanner, allowVarRef bool, tk *Token) (tree *term, err error) {
 	args := make([]*term, 0, 10)
 	itemExpected := false
 	lastSym := SymUnknown
 	for lastSym != SymClosedRound && lastSym != SymEos {
 		var subTree *ast
-		if subTree, err = self.parseItem(scanner, allowVarRef, SymComma, SymClosedRound); err != nil {
+		if subTree, err = parser.parseItem(scanner, allowVarRef, SymComma, SymClosedRound); err != nil {
 			break
 		}
 		prev := scanner.Previous()
@@ -48,7 +48,7 @@ func (self *parser) parseFuncCall(scanner *scanner, allowVarRef bool, tk *Token)
 	return
 }
 
-func (self *parser) parseFuncDef(scanner *scanner) (tree *term, err error) {
+func (parser *parser) parseFuncDef(scanner *scanner) (tree *term, err error) {
 	// Example: "add = func(x,y) {x+y}
 	var body *ast
 	args := make([]*term, 0)
@@ -65,7 +65,7 @@ func (self *parser) parseFuncDef(scanner *scanner) (tree *term, err error) {
 			if tk.Sym == SymEqual {
 				var paramExpr *ast
 				defaultParamsStarted = true
-				if paramExpr, err = self.parseItem(scanner, false, SymComma, SymClosedRound); err != nil {
+				if paramExpr, err = parser.parseItem(scanner, false, SymComma, SymClosedRound); err != nil {
 					break
 				}
 				param.forceChild(paramExpr.root)
@@ -88,7 +88,7 @@ func (self *parser) parseFuncDef(scanner *scanner) (tree *term, err error) {
 	if err == nil {
 		tk = scanner.Next()
 		if tk.IsSymbol(SymOpenBrace) {
-			body, err = self.parseGeneral(scanner, true, true, SymClosedBrace)
+			body, err = parser.parseGeneral(scanner, true, true, SymClosedBrace)
 		} else {
 			err = tk.ErrorExpectedGot("{")
 		}
@@ -104,7 +104,7 @@ func (self *parser) parseFuncDef(scanner *scanner) (tree *term, err error) {
 	return
 }
 
-func (self *parser) parseList(scanner *scanner, parsingIndeces bool, allowVarRef bool) (subtree *term, err error) {
+func (parser *parser) parseList(scanner *scanner, parsingIndeces bool, allowVarRef bool) (subtree *term, err error) {
 	r, c := scanner.lastPos()
 	args := make([]*term, 0)
 	lastSym := SymUnknown
@@ -112,7 +112,7 @@ func (self *parser) parseList(scanner *scanner, parsingIndeces bool, allowVarRef
 	for lastSym != SymClosedSquare && lastSym != SymEos {
 		var subTree *ast
 		zeroRequired := scanner.current.Sym == SymColon
-		if subTree, err = self.parseItem(scanner, allowVarRef, SymComma, SymClosedSquare); err == nil {
+		if subTree, err = parser.parseItem(scanner, allowVarRef, SymComma, SymClosedSquare); err == nil {
 			root := subTree.root
 			if root != nil {
 				if !parsingIndeces && root.symbol() == SymColon {
@@ -153,14 +153,14 @@ func (self *parser) parseList(scanner *scanner, parsingIndeces bool, allowVarRef
 	return
 }
 
-func (self *parser) parseIterDef(scanner *scanner, allowVarRef bool) (subtree *term, err error) {
+func (parser *parser) parseIterDef(scanner *scanner, allowVarRef bool) (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 = self.parseItem(scanner, allowVarRef, SymComma, SymClosedRound); err == nil {
+		if subTree, err = parser.parseItem(scanner, allowVarRef, SymComma, SymClosedRound); err == nil {
 			if subTree.root != nil {
 				args = append(args, subTree.root)
 			} else if itemExpected {
@@ -184,7 +184,7 @@ func (self *parser) parseIterDef(scanner *scanner, allowVarRef bool) (subtree *t
 	return
 }
 
-func (self *parser) parseDictKey(scanner *scanner, allowVarRef bool) (key any, err error) {
+func (parser *parser) parseDictKey(scanner *scanner, allowVarRef bool) (key any, err error) {
 	tk := scanner.Next()
 	if tk.Sym == SymError {
 		err = tk.Error()
@@ -206,14 +206,14 @@ func (self *parser) parseDictKey(scanner *scanner, allowVarRef bool) (key any, e
 	return
 }
 
-func (self *parser) parseDictionary(scanner *scanner, allowVarRef bool) (subtree *term, err error) {
+func (parser *parser) parseDictionary(scanner *scanner, allowVarRef bool) (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 = self.parseDictKey(scanner, allowVarRef); err != nil {
+		if key, err = parser.parseDictKey(scanner, allowVarRef); err != nil {
 			break
 		} else if key == nil {
 			tk := scanner.Previous()
@@ -223,10 +223,10 @@ func (self *parser) parseDictionary(scanner *scanner, allowVarRef bool) (subtree
 			}
 			break
 		}
-		if subTree, err = self.parseItem(scanner, allowVarRef, SymComma, SymClosedBrace); err == nil {
+		if subTree, err = parser.parseItem(scanner, allowVarRef, SymComma, SymClosedBrace); err == nil {
 			if subTree.root != nil {
 				args[key] = subTree.root
-			} else if key != nil {
+			} else /*if key != nil*/ {
 				prev := scanner.Previous()
 				err = prev.ErrorExpectedGot("dictionary-value")
 				break
@@ -248,7 +248,7 @@ func (self *parser) parseDictionary(scanner *scanner, allowVarRef bool) (subtree
 	return
 }
 
-func (self *parser) parseSelectorCase(scanner *scanner, allowVarRef bool, defaultCase bool) (caseTerm *term, err error) {
+func (parser *parser) parseSelectorCase(scanner *scanner, allowVarRef bool, defaultCase bool) (caseTerm *term, err error) {
 	var filterList *term
 	var caseExpr *ast
 	tk := scanner.Next()
@@ -259,7 +259,7 @@ func (self *parser) parseSelectorCase(scanner *scanner, allowVarRef bool, defaul
 			err = tk.Errorf("case list in default clause")
 			return
 		}
-		if filterList, err = self.parseList(scanner, false, allowVarRef); err != nil {
+		if filterList, err = parser.parseList(scanner, false, allowVarRef); err != nil {
 			return
 		}
 		tk = scanner.Next()
@@ -270,7 +270,7 @@ func (self *parser) parseSelectorCase(scanner *scanner, allowVarRef bool, defaul
 	}
 
 	if tk.Sym == SymOpenBrace {
-		if caseExpr, err = self.parseGeneral(scanner, true, allowVarRef, SymClosedBrace); err != nil {
+		if caseExpr, err = parser.parseGeneral(scanner, true, allowVarRef, SymClosedBrace); err != nil {
 			return
 		}
 	} else {
@@ -296,25 +296,25 @@ func addSelectorCase(selectorTerm, caseTerm *term) {
 	caseTerm.parent = selectorTerm
 }
 
-func (self *parser) parseSelector(scanner *scanner, tree *ast, allowVarRef bool) (selectorTerm *term, err error) {
+func (parser *parser) parseSelector(scanner *scanner, tree *ast, allowVarRef bool) (selectorTerm *term, err error) {
 	var caseTerm *term
 	tk := scanner.makeToken(SymSelector, '?')
 	if selectorTerm, err = tree.addToken2(tk); err != nil {
 		return
 	}
 
-	if caseTerm, err = self.parseSelectorCase(scanner, allowVarRef, false); err == nil {
+	if caseTerm, err = parser.parseSelectorCase(scanner, allowVarRef, false); err == nil {
 		addSelectorCase(selectorTerm, caseTerm)
 	}
 	return
 }
 
-func (self *parser) parseItem(scanner *scanner, allowVarRef bool, termSymbols ...Symbol) (tree *ast, err error) {
-	return self.parseGeneral(scanner, false, allowVarRef, termSymbols...)
+func (parser *parser) parseItem(scanner *scanner, allowVarRef bool, termSymbols ...Symbol) (tree *ast, err error) {
+	return parser.parseGeneral(scanner, false, allowVarRef, termSymbols...)
 }
 
-func (self *parser) Parse(scanner *scanner, termSymbols ...Symbol) (tree *ast, err error) {
-	return self.parseGeneral(scanner, true, false, termSymbols...)
+func (parser *parser) Parse(scanner *scanner, termSymbols ...Symbol) (tree *ast, err error) {
+	return parser.parseGeneral(scanner, true, false, termSymbols...)
 }
 
 func couldBeACollection(t *term) bool {
@@ -333,7 +333,7 @@ func couldBeACollection(t *term) bool {
 // 	return areOut
 // }
 
-func (self *parser) parseGeneral(scanner *scanner, allowForest bool, allowVarRef bool, termSymbols ...Symbol) (tree *ast, err error) {
+func (parser *parser) parseGeneral(scanner *scanner, allowForest bool, allowVarRef bool, termSymbols ...Symbol) (tree *ast, err error) {
 	var selectorTerm *term = nil
 	var currentTerm *term = nil
 	var tk *Token
@@ -371,21 +371,21 @@ func (self *parser) parseGeneral(scanner *scanner, allowForest bool, allowVarRef
 		switch tk.Sym {
 		case SymOpenRound:
 			var subTree *ast
-			if subTree, err = self.parseGeneral(scanner, false, allowVarRef, SymClosedRound); err == nil {
+			if subTree, err = parser.parseGeneral(scanner, false, allowVarRef, SymClosedRound); err == nil {
 				subTree.root.priority = priValue
 				err = tree.addTerm(newExprTerm(subTree.root))
 				currentTerm = subTree.root
 			}
 		case SymFuncCall:
 			var funcCallTerm *term
-			if funcCallTerm, err = self.parseFuncCall(scanner, allowVarRef, tk); err == nil {
+			if funcCallTerm, err = parser.parseFuncCall(scanner, allowVarRef, tk); err == nil {
 				err = tree.addTerm(funcCallTerm)
 				currentTerm = funcCallTerm
 			}
 		case SymOpenSquare:
 			var listTerm *term
 			parsingIndeces := couldBeACollection(currentTerm)
-			if listTerm, err = self.parseList(scanner, parsingIndeces, allowVarRef); err == nil {
+			if listTerm, err = parser.parseList(scanner, parsingIndeces, allowVarRef); err == nil {
 				if parsingIndeces {
 					indexTk := NewToken(listTerm.tk.row, listTerm.tk.col, SymIndex, listTerm.source())
 					indexTerm := newTerm(indexTk)
@@ -402,7 +402,7 @@ func (self *parser) parseGeneral(scanner *scanner, allowForest bool, allowVarRef
 				err = currentTerm.Errorf(`selector-case outside of a selector context`)
 			} else {
 				var mapTerm *term
-				if mapTerm, err = self.parseDictionary(scanner, allowVarRef); err == nil {
+				if mapTerm, err = parser.parseDictionary(scanner, allowVarRef); err == nil {
 					err = tree.addTerm(mapTerm)
 					currentTerm = mapTerm
 				}
@@ -413,13 +413,13 @@ func (self *parser) parseGeneral(scanner *scanner, allowForest bool, allowVarRef
 			// }
 		case SymFuncDef:
 			var funcDefTerm *term
-			if funcDefTerm, err = self.parseFuncDef(scanner); err == nil {
+			if funcDefTerm, err = parser.parseFuncDef(scanner); err == nil {
 				err = tree.addTerm(funcDefTerm)
 				currentTerm = funcDefTerm
 			}
 		case SymDollarRound:
 			var iterDefTerm *term
-			if iterDefTerm, err = self.parseIterDef(scanner, allowVarRef); err == nil {
+			if iterDefTerm, err = parser.parseIterDef(scanner, allowVarRef); err == nil {
 				err = tree.addTerm(iterDefTerm)
 				currentTerm = iterDefTerm
 			}
@@ -430,13 +430,13 @@ func (self *parser) parseGeneral(scanner *scanner, allowForest bool, allowVarRef
 				currentTerm, err = tree.addToken2(tk)
 			}
 		case SymQuestion:
-			if selectorTerm, err = self.parseSelector(scanner, tree, allowVarRef); err == nil {
+			if selectorTerm, err = parser.parseSelector(scanner, tree, allowVarRef); err == nil {
 				currentTerm = selectorTerm
 			}
 		case SymColon, SymDoubleColon:
 			var caseTerm *term
 			if selectorTerm != nil {
-				if caseTerm, err = self.parseSelectorCase(scanner, allowVarRef, tk.Sym == SymDoubleColon); err == nil {
+				if caseTerm, err = parser.parseSelectorCase(scanner, allowVarRef, tk.Sym == SymDoubleColon); err == nil {
 					addSelectorCase(selectorTerm, caseTerm)
 					currentTerm = caseTerm
 					if tk.Sym == SymDoubleColon {

plugins.go

@@ -29,7 +29,7 @@ func pluginExists(name string) (exists bool) {
 
 func makePluginName(name string) (decorated string) {
 	var template string
-	if execName, err := os.Executable(); err != nil || strings.Index(execName, "debug") < 0 {
+	if execName, err := os.Executable(); err != nil || !strings.Contains(execName, "debug") {
 		template = "expr-%s-plugin.so"
 	} else {
 		template = "expr-%s-plugin.so.debug"

scanner.go

@@ -49,257 +49,257 @@ func DefaultTranslations() map[Symbol]Symbol {
 // 	return self.current
 // }
 
-func (self *scanner) readChar() (ch byte, err error) {
-	if ch, err = self.stream.ReadByte(); err == nil {
+func (scanner *scanner) readChar() (ch byte, err error) {
+	if ch, err = scanner.stream.ReadByte(); err == nil {
 		if ch == '\n' {
-			self.row++
-			self.column = 0
+			scanner.row++
+			scanner.column = 0
 		} else {
-			self.column++
+			scanner.column++
 		}
 	}
 	return
 }
 
-func (self *scanner) unreadChar() (err error) {
-	if err = self.stream.UnreadByte(); err == nil {
-		if self.column--; self.column == 0 {
-			if self.row--; self.row == 0 {
+func (scanner *scanner) unreadChar() (err error) {
+	if err = scanner.stream.UnreadByte(); err == nil {
+		if scanner.column--; scanner.column == 0 {
+			if scanner.row--; scanner.row == 0 {
 				err = errors.New("unread beyond the stream boundary")
 			} else {
-				self.column = 1
+				scanner.column = 1
 			}
 		}
 	}
 	return
 }
 
-func (self *scanner) lastPos() (r, c int) {
-	if self.prev != nil {
-		r = self.prev.row
-		c = self.prev.col
+func (scanner *scanner) lastPos() (r, c int) {
+	if scanner.prev != nil {
+		r = scanner.prev.row
+		c = scanner.prev.col
 	}
 	return
 }
 
-func (self *scanner) Previous() *Token {
-	return self.prev
+func (scanner *scanner) Previous() *Token {
+	return scanner.prev
 }
 
-func (self *scanner) Next() (tk *Token) {
-	self.prev = self.current
-	tk = self.current
-	self.current = self.fetchNextToken()
+func (scanner *scanner) Next() (tk *Token) {
+	scanner.prev = scanner.current
+	tk = scanner.current
+	scanner.current = scanner.fetchNextToken()
 	return tk
 }
 
-func (self *scanner) fetchNextToken() (tk *Token) {
+func (scanner *scanner) fetchNextToken() (tk *Token) {
 	var ch byte
-	if err := self.skipBlanks(); err != nil {
-		return self.makeErrorToken(err)
+	if err := scanner.skipBlanks(); err != nil {
+		return scanner.makeErrorToken(err)
 	}
 
 	escape := false
 	for {
-		ch, _ = self.readChar()
+		ch, _ = scanner.readChar()
 		switch ch {
 		case '+':
-			if next, _ := self.peek(); next == '+' {
-				tk = self.moveOn(SymDoublePlus, ch, next)
+			if next, _ := scanner.peek(); next == '+' {
+				tk = scanner.moveOn(SymDoublePlus, ch, next)
 			} else if next == '=' {
-				tk = self.moveOn(SymPlusEqual, ch, next)
+				tk = scanner.moveOn(SymPlusEqual, ch, next)
 			} else {
-				tk = self.makeToken(SymPlus, ch)
+				tk = scanner.makeToken(SymPlus, ch)
 			}
 		case '-':
-			if next, _ := self.peek(); next == '-' {
-				tk = self.moveOn(SymDoubleMinus, ch, next)
+			if next, _ := scanner.peek(); next == '-' {
+				tk = scanner.moveOn(SymDoubleMinus, ch, next)
 			} else if next == '=' {
-				tk = self.moveOn(SymMinusEqual, ch, next)
+				tk = scanner.moveOn(SymMinusEqual, ch, next)
 			} else {
-				tk = self.makeToken(SymMinus, ch)
+				tk = scanner.makeToken(SymMinus, ch)
 			}
 		case '*':
-			if next, _ := self.peek(); next == '*' {
-				tk = self.moveOn(SymDoubleStar, ch, next)
+			if next, _ := scanner.peek(); next == '*' {
+				tk = scanner.moveOn(SymDoubleStar, ch, next)
 				// } else if next == '/' {
 				// 	tk = self.moveOn(SymClosedComment, ch, next)
 			} else {
-				tk = self.makeToken(SymStar, ch)
+				tk = scanner.makeToken(SymStar, ch)
 			}
 		case '/':
-			if next, _ := self.peek(); next == '*' {
-				self.readChar()
-				tk = self.fetchBlockComment()
+			if next, _ := scanner.peek(); next == '*' {
+				scanner.readChar()
+				tk = scanner.fetchBlockComment()
 			} else if next == '/' {
-				self.readChar()
-				tk = self.fetchOnLineComment()
+				scanner.readChar()
+				tk = scanner.fetchOnLineComment()
 			} else {
-				tk = self.makeToken(SymSlash, ch)
+				tk = scanner.makeToken(SymSlash, ch)
 			}
 		case '\\':
 			if escape {
-				tk = self.makeToken(SymBackSlash, ch)
+				tk = scanner.makeToken(SymBackSlash, ch)
 				escape = false
 			} else {
 				escape = true
 			}
 		case '|':
-			if next, _ := self.peek(); next == '|' {
-				tk = self.moveOn(SymDoubleVertBar, ch, next)
+			if next, _ := scanner.peek(); next == '|' {
+				tk = scanner.moveOn(SymDoubleVertBar, ch, next)
 			} else {
-				tk = self.makeToken(SymVertBar, ch)
+				tk = scanner.makeToken(SymVertBar, ch)
 			}
 		case ',':
-			tk = self.makeToken(SymComma, ch)
+			tk = scanner.makeToken(SymComma, ch)
 		case '^':
-			tk = self.makeToken(SymCaret, ch)
+			tk = scanner.makeToken(SymCaret, ch)
 		case ':':
-			if next, _ := self.peek(); next == ':' {
-				tk = self.moveOn(SymDoubleColon, ch, next)
+			if next, _ := scanner.peek(); next == ':' {
+				tk = scanner.moveOn(SymDoubleColon, ch, next)
 			} else {
-				tk = self.makeToken(SymColon, ch)
+				tk = scanner.makeToken(SymColon, ch)
 			}
 		case ';':
-			tk = self.makeToken(SymSemiColon, ch)
+			tk = scanner.makeToken(SymSemiColon, ch)
 		case '.':
 			//if next, _ := self.peek(); next >= '0' && next <= '9' {
 			//	tk = self.parseNumber(ch)
 			//} else if next == '/' {
-			if next, _ := self.peek(); next == '/' {
-				tk = self.moveOn(SymDotSlash, ch, next)
+			if next, _ := scanner.peek(); next == '/' {
+				tk = scanner.moveOn(SymDotSlash, ch, next)
 			} else if next == '.' {
-				if next1, _ := self.peek(); next1 == '.' {
-					tk = self.moveOn(SymTripleDot, ch, next, next1)
+				if next1, _ := scanner.peek(); next1 == '.' {
+					tk = scanner.moveOn(SymTripleDot, ch, next, next1)
 				} else {
-					tk = self.moveOn(SymDoubleDot, ch, next)
+					tk = scanner.moveOn(SymDoubleDot, ch, next)
 				}
 			} else {
-				tk = self.makeToken(SymDot, ch)
+				tk = scanner.makeToken(SymDot, ch)
 			}
 		case '\'':
 			if escape {
-				tk = self.makeToken(SymQuote, ch)
+				tk = scanner.makeToken(SymQuote, ch)
 				escape = false
 			} else {
-				tk = self.fetchString(ch)
+				tk = scanner.fetchString(ch)
 			}
 		case '"':
 			if escape {
-				tk = self.makeToken(SymDoubleQuote, ch)
+				tk = scanner.makeToken(SymDoubleQuote, ch)
 				escape = false
 			} else {
-				tk = self.fetchString(ch)
+				tk = scanner.fetchString(ch)
 			}
 		case '`':
-			tk = self.makeToken(SymBackTick, ch)
+			tk = scanner.makeToken(SymBackTick, ch)
 		case '!':
-			if next, _ := self.peek(); next == '=' {
-				tk = self.moveOn(SymNotEqual, ch, next)
+			if next, _ := scanner.peek(); next == '=' {
+				tk = scanner.moveOn(SymNotEqual, ch, next)
 			} else {
-				tk = self.makeToken(SymExclamation, ch)
+				tk = scanner.makeToken(SymExclamation, ch)
 			}
 		case '?':
-			if next, _ := self.peek(); next == '?' {
-				tk = self.moveOn(SymDoubleQuestion, ch, next)
+			if next, _ := scanner.peek(); next == '?' {
+				tk = scanner.moveOn(SymDoubleQuestion, ch, next)
 			} else if next == '=' {
-				tk = self.moveOn(SymQuestionEqual, ch, next)
+				tk = scanner.moveOn(SymQuestionEqual, ch, next)
 			} else if next == '!' {
-				tk = self.moveOn(SymQuestionExclam, ch, next)
+				tk = scanner.moveOn(SymQuestionExclam, ch, next)
 			} else {
-				tk = self.makeToken(SymQuestion, ch)
+				tk = scanner.makeToken(SymQuestion, ch)
 			}
 		case '&':
-			if next, _ := self.peek(); next == '&' {
-				tk = self.moveOn(SymDoubleAmpersand, ch, next)
+			if next, _ := scanner.peek(); next == '&' {
+				tk = scanner.moveOn(SymDoubleAmpersand, ch, next)
 			} else {
-				tk = self.makeToken(SymAmpersand, ch)
+				tk = scanner.makeToken(SymAmpersand, ch)
 			}
 		case '%':
-			tk = self.makeToken(SymPercent, ch)
+			tk = scanner.makeToken(SymPercent, ch)
 		case '#':
-			tk = self.makeToken(SymHash, ch)
+			tk = scanner.makeToken(SymHash, ch)
 		case '@':
-			if next, _ := self.peek(); (next >= 'a' && next <= 'z') || (next >= 'A' && next <= 'Z') {
-				self.readChar()
-				if tk = self.fetchIdentifier(next); tk.Sym == SymIdentifier {
+			if next, _ := scanner.peek(); (next >= 'a' && next <= 'z') || (next >= 'A' && next <= 'Z') {
+				scanner.readChar()
+				if tk = scanner.fetchIdentifier(next); tk.Sym == SymIdentifier {
 					//tk.Sym = SymIdRef
 					tk.source = "@" + tk.source
 				} else {
-					tk = self.makeErrorToken(fmt.Errorf("invalid variable reference %q", tk.source))
+					tk = scanner.makeErrorToken(fmt.Errorf("invalid variable reference %q", tk.source))
 				}
 			} else if next == '@' {
-				tk = self.moveOn(SymDoubleAt, ch, next)
+				tk = scanner.moveOn(SymDoubleAt, ch, next)
 			} else {
-				tk = self.makeToken(SymAt, ch)
+				tk = scanner.makeToken(SymAt, ch)
 			}
 		case '_':
-			tk = self.makeToken(SymUndescore, ch)
+			tk = scanner.makeToken(SymUndescore, ch)
 		case '=':
-			if next, _ := self.peek(); next == '=' {
-				tk = self.moveOn(SymDoubleEqual, ch, next)
+			if next, _ := scanner.peek(); next == '=' {
+				tk = scanner.moveOn(SymDoubleEqual, ch, next)
 			} else {
-				tk = self.makeToken(SymEqual, ch)
+				tk = scanner.makeToken(SymEqual, ch)
 			}
 		case '<':
-			if next, _ := self.peek(); next == '=' {
-				tk = self.moveOn(SymLessOrEqual, ch, next)
+			if next, _ := scanner.peek(); next == '=' {
+				tk = scanner.moveOn(SymLessOrEqual, ch, next)
 			} else if next == '<' {
-				tk = self.moveOn(SymAppend, ch, next)
+				tk = scanner.moveOn(SymAppend, ch, next)
 			} else if next == '>' {
-				tk = self.moveOn(SymLessGreater, ch, next)
+				tk = scanner.moveOn(SymLessGreater, ch, next)
 			} else {
-				tk = self.makeToken(SymLess, ch)
+				tk = scanner.makeToken(SymLess, ch)
 			}
 		case '>':
-			if next, _ := self.peek(); next == '=' {
-				tk = self.moveOn(SymGreaterOrEqual, ch, next)
+			if next, _ := scanner.peek(); next == '=' {
+				tk = scanner.moveOn(SymGreaterOrEqual, ch, next)
 			} else if next == '>' {
-				tk = self.moveOn(SymInsert, ch, next)
+				tk = scanner.moveOn(SymInsert, ch, next)
 			} else {
-				tk = self.makeToken(SymGreater, ch)
+				tk = scanner.makeToken(SymGreater, ch)
 			}
 		case '$':
-			if next, _ := self.peek(); next == '(' {
-				tk = self.moveOn(SymDollarRound, ch, next)
+			if next, _ := scanner.peek(); next == '(' {
+				tk = scanner.moveOn(SymDollarRound, ch, next)
 				tk.source += ")"
 			} else if next == '$' {
-				tk = self.moveOn(SymDoubleDollar, ch, next)
+				tk = scanner.moveOn(SymDoubleDollar, ch, next)
 			} else {
-				tk = self.makeToken(SymDollar, ch)
+				tk = scanner.makeToken(SymDollar, ch)
 			}
 		case '(':
-			if next, _ := self.peek(); next == ')' {
-				tk = self.moveOn(SymOpenClosedRound, ch, next)
+			if next, _ := scanner.peek(); next == ')' {
+				tk = scanner.moveOn(SymOpenClosedRound, ch, next)
 			} else {
-				tk = self.makeToken(SymOpenRound, ch)
+				tk = scanner.makeToken(SymOpenRound, ch)
 			}
 		case ')':
-			tk = self.makeToken(SymClosedRound, ch)
+			tk = scanner.makeToken(SymClosedRound, ch)
 		case '[':
-			tk = self.makeToken(SymOpenSquare, ch)
+			tk = scanner.makeToken(SymOpenSquare, ch)
 		case ']':
-			tk = self.makeToken(SymClosedSquare, ch)
+			tk = scanner.makeToken(SymClosedSquare, ch)
 		case '{':
-			tk = self.makeToken(SymOpenBrace, ch)
+			tk = scanner.makeToken(SymOpenBrace, ch)
 		case '}':
-			tk = self.makeToken(SymClosedBrace, ch)
+			tk = scanner.makeToken(SymClosedBrace, ch)
 		case '~':
-			tk = self.makeToken(SymTilde, ch)
+			tk = scanner.makeToken(SymTilde, ch)
 		case 0:
 			if escape {
-				tk = self.makeErrorToken(errors.New("incomplete escape sequence"))
+				tk = scanner.makeErrorToken(errors.New("incomplete escape sequence"))
 			}
 			escape = false
 		default:
 			if /*ch == '_' ||*/ (ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z') {
-				if tk = self.fetchIdentifier(ch); tk.Sym == SymKwFunc {
-					if next, _ := self.peek(); next == '(' {
-						tk = self.moveOn(SymFuncDef, ch, next)
+				if tk = scanner.fetchIdentifier(ch); tk.Sym == SymKwFunc {
+					if next, _ := scanner.peek(); next == '(' {
+						tk = scanner.moveOn(SymFuncDef, ch, next)
 					}
 				}
 			} else if ch >= '0' && ch <= '9' {
-				tk = self.parseNumber(ch)
+				tk = scanner.parseNumber(ch)
 			}
 		}
 		if !escape {
@@ -307,14 +307,14 @@ func (self *scanner) fetchNextToken() (tk *Token) {
 		}
 	}
 	if tk == nil {
-		tk = NewErrorToken(self.row, self.column, fmt.Errorf("unknown symbol '%c'", ch))
+		tk = NewErrorToken(scanner.row, scanner.column, fmt.Errorf("unknown symbol '%c'", ch))
 	}
 	return
 }
 
-func (self *scanner) sync(err error) error {
+func (scanner *scanner) sync(err error) error {
 	if err == nil {
-		err = self.unreadChar()
+		err = scanner.unreadChar()
 	}
 	return err
 }
@@ -335,32 +335,32 @@ func isHexDigit(ch byte) bool {
 	return (ch >= '0' && ch <= '9') || (ch >= 'a' && ch <= 'f') || (ch >= 'A' && ch <= 'F')
 }
 
-func (self *scanner) initBase(sb *strings.Builder, currentFirstCh byte) (firstCh byte, numBase int, digitFunc func(byte) bool, err error) {
+func (scanner *scanner) initBase(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 = self.peek(); err == nil {
+	if ch, err = scanner.peek(); err == nil {
 		if ch == 'b' || ch == 'B' {
 			numBase = 2
 			digitType = "binary"
-			self.readChar()
+			scanner.readChar()
 			digitFunc = isBinaryDigit
-			firstCh, err = self.readChar()
+			firstCh, err = scanner.readChar()
 		} else if ch == 'o' || ch == 'O' {
 			numBase = 8
 			digitType = "octal"
-			self.readChar()
+			scanner.readChar()
 			digitFunc = isOctalDigit
-			firstCh, err = self.readChar()
+			firstCh, err = scanner.readChar()
 		} else if ch == 'x' || ch == 'X' {
 			numBase = 16
 			digitType = "hex"
-			self.readChar()
+			scanner.readChar()
 			digitFunc = isHexDigit
-			firstCh, err = self.readChar()
+			firstCh, err = scanner.readChar()
 		}
 		if err == nil && !digitFunc(firstCh) {
 			if len(digitType) == 0 {
@@ -374,7 +374,7 @@ func (self *scanner) initBase(sb *strings.Builder, currentFirstCh byte) (firstCh
 	return
 }
 
-func (self *scanner) parseNumber(firstCh byte) (tk *Token) {
+func (scanner *scanner) parseNumber(firstCh byte) (tk *Token) {
 	var err error
 	var ch byte
 	var sym Symbol = SymInteger
@@ -383,9 +383,9 @@ func (self *scanner) parseNumber(firstCh byte) (tk *Token) {
 	var numBase = 10
 
 	if firstCh == '0' {
-		firstCh, numBase, isDigit, err = self.initBase(&sb, firstCh)
+		firstCh, numBase, isDigit, err = scanner.initBase(firstCh)
 	}
-	for ch = firstCh; err == nil && isDigit(ch); ch, err = self.readChar() {
+	for ch = firstCh; err == nil && isDigit(ch); ch, err = scanner.readChar() {
 		sb.WriteByte(ch)
 	}
 
@@ -393,9 +393,9 @@ func (self *scanner) parseNumber(firstCh byte) (tk *Token) {
 		if err == nil && ch == '.' {
 			sym = SymFloat
 			sb.WriteByte(ch)
-			ch, err = self.readChar()
+			ch, err = scanner.readChar()
 			if ch >= '0' && ch <= '9' {
-				for ; err == nil && (ch >= '0' && ch <= '9'); ch, err = self.readChar() {
+				for ; err == nil && (ch >= '0' && ch <= '9'); ch, err = scanner.readChar() {
 					sb.WriteByte(ch)
 				}
 			}
@@ -404,32 +404,32 @@ func (self *scanner) parseNumber(firstCh byte) (tk *Token) {
 			if ch == 'e' || ch == 'E' {
 				sym = SymFloat
 				sb.WriteByte(ch)
-				if ch, err = self.readChar(); err == nil {
+				if ch, err = scanner.readChar(); err == nil {
 					if ch == '+' || ch == '-' {
 						sb.WriteByte(ch)
-						ch, err = self.readChar()
+						ch, err = scanner.readChar()
 					}
 					if ch >= '0' && ch <= '9' {
-						for ; err == nil && (ch >= '0' && ch <= '9'); ch, err = self.readChar() {
+						for ; err == nil && (ch >= '0' && ch <= '9'); ch, err = scanner.readChar() {
 							sb.WriteByte(ch)
 						}
 					} else {
-						err = fmt.Errorf("[%d:%d] expected integer exponent, got %c", self.row, self.column, ch)
+						err = fmt.Errorf("[%d:%d] expected integer exponent, got %c", scanner.row, scanner.column, ch)
 					}
 				}
 			} else if ch == '(' {
 				sym = SymFraction
 				sb.WriteByte(ch)
-				ch, err = self.readChar()
-				for ; err == nil && (ch >= '0' && ch <= '9'); ch, err = self.readChar() {
+				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'", self.row, self.column, ch)
+						err = fmt.Errorf("[%d:%d] expected ')', got '%c'", scanner.row, scanner.column, ch)
 					} else {
 						sb.WriteByte(ch)
-						_, err = self.readChar()
+						_, err = scanner.readChar()
 					}
 				}
 			}
@@ -437,10 +437,10 @@ func (self *scanner) parseNumber(firstCh byte) (tk *Token) {
 	}
 
 	if err != nil && err != io.EOF {
-		tk = self.makeErrorToken(err)
+		tk = scanner.makeErrorToken(err)
 	} else {
 		var value any
-		err = self.sync(err)
+		err = scanner.sync(err)	// TODO: Check this function
 		txt := sb.String()
 		if sym == SymFloat {
 			value, err = strconv.ParseFloat(txt, 64)
@@ -450,39 +450,39 @@ func (self *scanner) parseNumber(firstCh byte) (tk *Token) {
 			value, err = strconv.ParseInt(txt, numBase, 64)
 		}
 		if err == nil {
-			tk = self.makeValueToken(sym, txt, value)
+			tk = scanner.makeValueToken(sym, txt, value)
 		} else {
-			tk = self.makeErrorToken(err)
+			tk = scanner.makeErrorToken(err)
 		}
 	}
 	return
 }
 
-func (self *scanner) fetchIdentifier(firstCh byte) (tk *Token) {
+func (scanner *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 = self.readChar() {
+	for ch := firstCh; err == nil && (ch == '_' || (ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z') || (ch >= '0' && ch <= '9')); ch, err = scanner.readChar() {
 		sb.WriteByte(ch)
 	}
 
 	if err != nil && err != io.EOF {
-		tk = self.makeErrorToken(err)
-	} else if err = self.sync(err); err != nil && err != io.EOF {
-		tk = self.makeErrorToken(err)
+		tk = scanner.makeErrorToken(err)
+	} else if err = scanner.sync(err); err != nil && err != io.EOF {
+		tk = scanner.makeErrorToken(err)
 	} else {
 		txt := sb.String()
 		uptxt := strings.ToUpper(txt)
 		if sym, ok := keywords[uptxt]; ok {
-			tk = self.makeKeywordToken(sym, uptxt)
+			tk = scanner.makeKeywordToken(sym, uptxt)
 		} else if uptxt == `TRUE` {
-			tk = self.makeValueToken(SymBool, txt, true)
+			tk = scanner.makeValueToken(SymBool, txt, true)
 		} else if uptxt == `FALSE` {
-			tk = self.makeValueToken(SymBool, txt, false)
-		} else if ch, _ := self.peek(); ch == '(' {
-			self.readChar()
-			tk = self.makeValueToken(SymFuncCall, txt+"(", txt)
+			tk = scanner.makeValueToken(SymBool, txt, false)
+		} else if ch, _ := scanner.peek(); ch == '(' {
+			scanner.readChar()
+			tk = scanner.makeValueToken(SymFuncCall, txt+"(", txt)
 		} else {
-			tk = self.makeValueToken(SymIdentifier, txt, txt)
+			tk = scanner.makeValueToken(SymIdentifier, txt, txt)
 		}
 	}
 
@@ -502,29 +502,29 @@ func (self *scanner) fetchIdentifier(firstCh byte) (tk *Token) {
 	return
 }
 
-func (self *scanner) fetchBlockComment() *Token {
-	return self.fetchUntil(SymComment, false, '*', '/')
+func (scanner *scanner) fetchBlockComment() *Token {
+	return scanner.fetchUntil(SymComment, false, '*', '/')
 }
 
-func (self *scanner) fetchOnLineComment() *Token {
-	return self.fetchUntil(SymComment, true, '\n')
+func (scanner *scanner) fetchOnLineComment() *Token {
+	return scanner.fetchUntil(SymComment, true, '\n')
 }
 
-func (self *scanner) fetchUntil(sym Symbol, allowEos bool, endings ...byte) (tk *Token) {
+func (scanner *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 = self.readChar(); err == nil && !endReached; {
+	for ch, err = scanner.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 = self.readChar()
+			ch, err = scanner.readChar()
 		}
 	}
 	if !endReached && allowEos {
@@ -533,18 +533,18 @@ func (self *scanner) fetchUntil(sym Symbol, allowEos bool, endings ...byte) (tk
 	}
 
 	if endReached {
-		tk = self.makeValueToken(sym, "", value)
+		tk = scanner.makeValueToken(sym, "", value)
 	} else {
-		tk = self.makeErrorToken(err)
+		tk = scanner.makeErrorToken(err)
 	}
 	return
 }
 
-func (self *scanner) fetchString(termCh byte) (tk *Token) {
+func (scanner *scanner) fetchString(termCh byte) (tk *Token) {
 	var err error
 	var ch, prev byte
 	var sb strings.Builder
-	for ch, err = self.readChar(); err == nil; ch, err = self.readChar() {
+	for ch, err = scanner.readChar(); err == nil; ch, err = scanner.readChar() {
 		if prev == '\\' {
 			switch ch {
 			case '"':
@@ -572,65 +572,65 @@ func (self *scanner) fetchString(termCh byte) (tk *Token) {
 	}
 	if err != nil {
 		if err == io.EOF {
-			tk = self.makeErrorToken(errors.New("missing string termination \""))
+			tk = scanner.makeErrorToken(errors.New("missing string termination \""))
 		} else {
-			tk = self.makeErrorToken(err)
+			tk = scanner.makeErrorToken(err)
 		}
 	} else {
 		txt := sb.String()
-		tk = self.makeValueToken(SymString, `"`+txt+`"`, txt)
+		tk = scanner.makeValueToken(SymString, `"`+txt+`"`, txt)
 	}
 	return
 }
 
-func (self *scanner) peek() (next byte, err error) {
+func (scanner *scanner) peek() (next byte, err error) {
 	var one []byte
-	if one, err = self.stream.Peek(1); err == nil {
+	if one, err = scanner.stream.Peek(1); err == nil {
 		next = one[0]
 	}
 	return
 }
 
-func (self *scanner) skipBlanks() (err error) {
+func (scanner *scanner) skipBlanks() (err error) {
 	var one []byte
-	for one, err = self.stream.Peek(1); err == nil && one[0] <= 32; one, err = self.stream.Peek(1) {
-		self.readChar()
+	for one, err = scanner.stream.Peek(1); err == nil && one[0] <= 32; one, err = scanner.stream.Peek(1) {
+		scanner.readChar()
 	}
 	return
 }
 
-func (self *scanner) translate(sym Symbol) Symbol {
-	if self.translations != nil {
-		if translatedSym, ok := self.translations[sym]; ok {
+func (scanner *scanner) translate(sym Symbol) Symbol {
+	if scanner.translations != nil {
+		if translatedSym, ok := scanner.translations[sym]; ok {
 			return translatedSym
 		}
 	}
 	return sym
 }
 
-func (self *scanner) moveOn(sym Symbol, chars ...byte) (tk *Token) {
-	tk = NewToken(self.row, self.column, self.translate(sym), string(chars))
+func (scanner *scanner) moveOn(sym Symbol, chars ...byte) (tk *Token) {
+	tk = NewToken(scanner.row, scanner.column, scanner.translate(sym), string(chars))
 	for i := 1; i < len(chars); i++ {
-		self.readChar()
+		scanner.readChar()
 	}
 	return
 }
 
-func (self *scanner) makeToken(sym Symbol, chars ...byte) (tk *Token) {
-	tk = NewToken(self.row, self.column, self.translate(sym), string(chars))
+func (scanner *scanner) makeToken(sym Symbol, chars ...byte) (tk *Token) {
+	tk = NewToken(scanner.row, scanner.column, scanner.translate(sym), string(chars))
 	return
 }
 
-func (self *scanner) makeKeywordToken(sym Symbol, upperCaseKeyword string) (tk *Token) {
-	tk = NewToken(self.row, self.column, self.translate(sym), upperCaseKeyword)
+func (scanner *scanner) makeKeywordToken(sym Symbol, upperCaseKeyword string) (tk *Token) {
+	tk = NewToken(scanner.row, scanner.column, scanner.translate(sym), upperCaseKeyword)
 	return
 }
 
-func (self *scanner) makeValueToken(sym Symbol, source string, value any) (tk *Token) {
-	tk = NewValueToken(self.row, self.column, self.translate(sym), source, value)
+func (scanner *scanner) makeValueToken(sym Symbol, source string, value any) (tk *Token) {
+	tk = NewValueToken(scanner.row, scanner.column, scanner.translate(sym), source, value)
 	return
 }
 
-func (self *scanner) makeErrorToken(err error) *Token {
-	return NewErrorToken(self.row, self.column, err)
+func (scanner *scanner) makeErrorToken(err error) *Token {
+	return NewErrorToken(scanner.row, scanner.column, err)
 }

simple-store.go

@@ -25,7 +25,7 @@ func NewSimpleStore() *SimpleStore {
 }
 
 func filterRefName(name string) bool  { return name[0] != '@' }
-func filterPrivName(name string) bool { return name[0] != '_' }
+//func filterPrivName(name string) bool { return name[0] != '_' }
 
 func (ctx *SimpleStore) SetParent(parentCtx ExprContext) {
 	ctx.parent = parentCtx

t_scanner_test.go

@@ -6,7 +6,6 @@ package expr
 
 import (
 	"errors"
-	"fmt"
 	"reflect"
 	"strings"
 	"testing"
@@ -69,9 +68,9 @@ func TestScanner(t *testing.T) {
 		// 	continue
 		// }
 		if input.wantErr == nil {
-			t.Log(fmt.Sprintf("[+]Test nr %2d -- %q", i+1, input.source))
+			t.Logf("[+]Test nr %2d -- %q", i+1, input.source)
 		} else {
-			t.Log(fmt.Sprintf("[-]Test nr %2d -- %q", i+1, input.source))
+			t.Logf("[-]Test nr %2d -- %q", i+1, input.source)
 		}
 
 		r := strings.NewReader(input.source)

term.go

@@ -53,21 +53,21 @@ type term struct {
 	evalFunc evalFuncType
 }
 
-func (self *term) String() string {
+func (term *term) String() string {
 	var sb strings.Builder
-	self.toString(&sb)
+	term.toString(&sb)
 	return sb.String()
 }
 
-func (self *term) toString(sb *strings.Builder) {
-	if self.position == posLeaf {
-		sb.WriteString(self.tk.String())
+func (term *term) toString(sb *strings.Builder) {
+	if term.position == posLeaf {
+		sb.WriteString(term.tk.String())
 	} else {
 		sb.WriteByte('[')
-		sb.WriteString(self.tk.String())
-		if self.children != nil {
+		sb.WriteString(term.tk.String())
+		if term.children != nil {
 			sb.WriteByte('(')
-			for i, c := range self.children {
+			for i, c := range term.children {
 				if i > 0 {
 					sb.WriteByte(' ')
 				}
@@ -79,17 +79,17 @@ func (self *term) toString(sb *strings.Builder) {
 	}
 }
 
-func (self *term) getChildrenCount() (count int) {
-	if self.position == posLeaf || self.children == nil {
+func (term *term) getChildrenCount() (count int) {
+	if term.position == posLeaf || term.children == nil {
 		count = 0
 	} else {
-		count = len(self.children)
+		count = len(term.children)
 	}
 	return
 }
 
-func (self *term) getRoom() (room int) {
-	switch self.position {
+func (term *term) getRoom() (room int) {
+	switch term.position {
 	case posLeaf:
 		room = 0
 	case posInfix:
@@ -102,139 +102,139 @@ func (self *term) getRoom() (room int) {
 	return
 }
 
-func (self *term) isComplete() bool {
-	return self.getChildrenCount() == self.getRoom()
+func (term *term) isComplete() bool {
+	return term.getChildrenCount() == term.getRoom()
 }
 
-func (self *term) removeLastChild() (child *term) {
-	if self.children != nil {
-		child = self.children[len(self.children)-1]
-		self.children = self.children[0 : len(self.children)-1]
+func (term *term) removeLastChild() (child *term) {
+	if term.children != nil {
+		child = term.children[len(term.children)-1]
+		term.children = term.children[0 : len(term.children)-1]
 	} else {
 		panic("Can't get last child")
 	}
 	return
 }
 
-func (self *term) isLeaf() bool {
-	return self.position == posLeaf
+func (term *term) isLeaf() bool {
+	return term.position == posLeaf
 }
 
-func (self *term) getPriority() termPriority {
-	return self.priority
+func (term *term) getPriority() termPriority {
+	return term.priority
 }
 
-func (self *term) setParent(parent *term) {
-	self.parent = parent
+func (term *term) setParent(parent *term) {
+	term.parent = parent
 	if parent != nil && len(parent.children) < cap(parent.children) {
-		parent.children = append(parent.children, self)
+		parent.children = append(parent.children, term)
 	}
 }
 
-func (self *term) symbol() Symbol {
-	return self.tk.Sym
+func (term *term) symbol() Symbol {
+	return term.tk.Sym
 }
 
-func (self *term) source() string {
-	return self.tk.source
+func (term *term) source() string {
+	return term.tk.source
 }
 
-func (self *term) value() any {
-	return self.tk.Value
+func (term *term) value() any {
+	return term.tk.Value
 }
 
-func (self *term) compute(ctx ExprContext) (v any, err error) {
-	if self.evalFunc == nil {
-		err = self.tk.Errorf("undefined eval-func for %q term", self.source())
+func (term *term) compute(ctx ExprContext) (v any, err error) {
+	if term.evalFunc == nil {
+		err = term.tk.Errorf("undefined eval-func for %q term", term.source())
 	} else {
-		v, err = self.evalFunc(ctx, self)
+		v, err = term.evalFunc(ctx, term)
 	}
 	return
 }
 
-func (self *term) toInt(computedValue any, valueDescription string) (i int, err error) {
-	if index64, ok := computedValue.(int64); ok {
-		i = int(index64)
-	} else {
-		err = self.Errorf("%s, got %s (%v)", valueDescription, TypeName(computedValue), computedValue)
-	}
-	return
-}
+// func (term *term) toInt(computedValue any, valueDescription string) (i int, err error) {
+// 	if index64, ok := computedValue.(int64); ok {
+// 		i = int(index64)
+// 	} else {
+// 		err = term.Errorf("%s, got %s (%v)", valueDescription, TypeName(computedValue), computedValue)
+// 	}
+// 	return
+// }
 
-func (self *term) errIncompatibleTypes(leftValue, rightValue any) error {
+func (term *term) errIncompatibleTypes(leftValue, rightValue any) error {
 	leftType := TypeName(leftValue)
 	leftText := getFormatted(leftValue, Truncate)
 	rightType := TypeName(rightValue)
 	rightText := getFormatted(rightValue, Truncate)
-	return self.tk.Errorf(
+	return term.tk.Errorf(
 		"left operand '%s' [%s] and right operand '%s' [%s] are not compatible with operator %q",
 		leftText, leftType,
 		rightText, rightType,
-		self.source())
+		term.source())
 }
 
-func (self *term) errIncompatibleType(value any) error {
-	return self.tk.Errorf(
+func (term *term) errIncompatibleType(value any) error {
+	return term.tk.Errorf(
 		"prefix/postfix operator %q do not support operand '%v' [%s]",
-		self.source(), value, TypeName(value))
+		term.source(), value, TypeName(value))
 }
 
-func (self *term) Errorf(template string, args ...any) (err error) {
-	err = self.tk.Errorf(template, args...)
+func (term *term) Errorf(template string, args ...any) (err error) {
+	err = term.tk.Errorf(template, args...)
 	return
 }
 
-func (self *term) checkOperands() (err error) {
-	switch self.position {
+func (term *term) checkOperands() (err error) {
+	switch term.position {
 	case posInfix:
-		if self.children == nil || len(self.children) != 2 || self.anyChildrenNil() {
-			err = self.tk.Errorf("infix operator %q requires two non-nil operands, got %d", self.source(), self.getChildrenCount())
+		if term.children == nil || len(term.children) != 2 || term.anyChildrenNil() {
+			err = term.tk.Errorf("infix operator %q requires two non-nil operands, got %d", term.source(), term.getChildrenCount())
 		}
 	case posPrefix:
-		if self.children == nil || len(self.children) != 1 || self.children[0] == nil {
-			err = self.tk.Errorf("prefix operator %q requires one not nil operand", self.tk.String())
+		if term.children == nil || len(term.children) != 1 || term.children[0] == nil {
+			err = term.tk.Errorf("prefix operator %q requires one not nil operand", term.tk.String())
 		}
 	case posPostfix:
-		if self.children == nil || len(self.children) != 1 || self.anyChildrenNil() {
-			err = self.tk.Errorf("postfix operator %q requires one not nil operand", self.tk.String())
+		if term.children == nil || len(term.children) != 1 || term.anyChildrenNil() {
+			err = term.tk.Errorf("postfix operator %q requires one not nil operand", term.tk.String())
 		}
 	case posMultifix:
-		if self.children == nil || len(self.children) < 3 || self.anyChildrenNil() {
-			err = self.tk.Errorf("infix operator %q requires at least three not operands, got %d", self.source(), self.getChildrenCount())
+		if term.children == nil || len(term.children) < 3 || term.anyChildrenNil() {
+			err = term.tk.Errorf("infix operator %q requires at least three not operands, got %d", term.source(), term.getChildrenCount())
 		}
 	}
 	return
 }
 
-func (self *term) anyChildrenNil() bool {
-	for _, child := range self.children {
+func (term *term) anyChildrenNil() bool {
+	for _, child := range term.children {
 		if child == nil {
 			return true
 		}
 	}
 	return false
 }
-func (self *term) evalInfix(ctx ExprContext) (leftValue, rightValue any, err error) {
-	if err = self.checkOperands(); err == nil {
-		if leftValue, err = self.children[0].compute(ctx); err == nil {
-			rightValue, err = self.children[1].compute(ctx)
+func (term *term) evalInfix(ctx ExprContext) (leftValue, rightValue any, err error) {
+	if err = term.checkOperands(); err == nil {
+		if leftValue, err = term.children[0].compute(ctx); err == nil {
+			rightValue, err = term.children[1].compute(ctx)
 		}
 	}
 	return
 }
 
-func (self *term) evalPrefix(ctx ExprContext) (childValue any, err error) {
-	if err = self.checkOperands(); err == nil {
-		childValue, err = self.children[0].compute(ctx)
+func (term *term) evalPrefix(ctx ExprContext) (childValue any, err error) {
+	if err = term.checkOperands(); err == nil {
+		childValue, err = term.children[0].compute(ctx)
 	}
 	return
 }
 
 // NOTE Temporary solution to support function parameters with default value
 
-func (self *term) forceChild(c *term) {
-	if self.children == nil {
-		self.children = make([]*term, 0, 1)
+func (t *term) forceChild(c *term) {
+	if t.children == nil {
+		t.children = make([]*term, 0, 1)
 	}
-	self.children = append(self.children, c)
+	t.children = append(t.children, c)
 }

token.go

@@ -33,7 +33,7 @@ func (tk *Token) String() string {
 			return fmt.Sprintf("%v", tk.Value)
 		}
 	}
-	return fmt.Sprintf("%s", tk.source)
+	return tk.source
 }
 
 func NewToken(row, col int, sym Symbol, source string) *Token {
@@ -71,31 +71,31 @@ func (tk *Token) IsSymbol(sym Symbol) bool {
 	return tk.Sym == sym
 }
 
-func (self *Token) Errorf(template string, args ...any) (err error) {
-	err = fmt.Errorf(fmt.Sprintf("[%d:%d] ", self.row, self.col)+template, args...)
+func (tk *Token) Errorf(template string, args ...any) (err error) {
+	err = fmt.Errorf(fmt.Sprintf("[%d:%d] ", tk.row, tk.col)+template, args...)
 	return
 }
 
-func (self *Token) Error() (err error) {
-	if self.Sym == SymError {
-		if msg, ok := self.Value.(error); ok {
-			err = fmt.Errorf("[%d:%d] %v", self.row, self.col, msg)
+func (tk *Token) Error() (err error) {
+	if tk.Sym == SymError {
+		if msg, ok := tk.Value.(error); ok {
+			err = fmt.Errorf("[%d:%d] %v", tk.row, tk.col, msg)
 		}
 	}
 	return
 }
 
-func (self *Token) Errors(msg string) (err error) {
-	err = fmt.Errorf("[%d:%d] %v", self.row, self.col, msg)
+func (tk *Token) Errors(msg string) (err error) {
+	err = fmt.Errorf("[%d:%d] %v", tk.row, tk.col, msg)
 	return
 }
 
-func (self *Token) ErrorExpectedGot(symbol string) (err error) {
-	err = fmt.Errorf("[%d:%d] expected %q, got %q", self.row, self.col, symbol, self)
+func (tk *Token) ErrorExpectedGot(symbol string) (err error) {
+	err = fmt.Errorf("[%d:%d] expected %q, got %q", tk.row, tk.col, symbol, tk)
 	return
 }
 
-func (self *Token) ErrorExpectedGotString(symbol, got string) (err error) {
-	err = fmt.Errorf("[%d:%d] expected %q, got %q", self.row, self.col, symbol, got)
+func (tk *Token) ErrorExpectedGotString(symbol, got string) (err error) {
+	err = fmt.Errorf("[%d:%d] expected %q, got %q", tk.row, tk.col, symbol, got)
 	return
 }