new operator 'map' ans general variable access by ${}

Also made a litle change to scanner function moveOn(): now it moves on
the last char passed and only if there are more than one chars.

README.adoc

@@ -144,4 +144,4 @@ Variables and functions can be added to a context both programmatically and ad a
 
 == Expressions syntax
 
-See #TODO link to doc/Expr.html#
+See https://cdn.paas.portale-stac.it/howto/go-pkg/expr/doc/Expr.html[Expr documentation] for a complete reference of the expression syntax and available functions.

builtin-base.go

@@ -72,6 +72,10 @@ func boolFunc(ctx ExprContext, name string, args map[string]any) (result any, er
 		result = v
 	case string:
 		result = len(v) > 0
+	case *ListType:
+		result = len(*v) > 0
+	case *DictType:
+		result = len(*v) > 0
 	default:
 		err = ErrCantConvert(name, v, "bool")
 	}
@@ -95,6 +99,8 @@ func intFunc(ctx ExprContext, name string, args map[string]any) (result any, err
 		if i, err = strconv.Atoi(v); err == nil {
 			result = int64(i)
 		}
+	case *FractionType:
+		result = int64(v.num / v.den)
 	default:
 		err = ErrCantConvert(name, v, "int")
 	}
@@ -211,6 +217,54 @@ func evalFunc(ctx ExprContext, name string, args map[string]any) (result any, er
 	return
 }
 
+func varFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
+	var varName string
+	var ok bool
+
+	if varName, ok = args[ParamName].(string); !ok {
+		return nil, ErrWrongParamType(name, ParamName, TypeString, args[ParamName])
+	}
+
+	if result, ok = args[ParamValue]; ok && result != nil {
+		ctx.GetParent().UnsafeSetVar(varName, result)
+		// } else {
+		// 	err = ErrWrongParamType(name, ParamSource, TypeString, args[ParamSource])
+		// }
+	} else if result, ok = ctx.GetVar(varName); !ok {
+		err = ErrUnknownVar(name, varName)
+	}
+	return
+}
+
+func setFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
+	var varName string
+	var ok bool
+
+	if varName, ok = args[ParamName].(string); !ok {
+		return nil, ErrWrongParamType(name, ParamName, TypeString, args[ParamName])
+	}
+
+	if result, ok = args[ParamValue]; ok {
+		ctx.GetParent().UnsafeSetVar(varName, result)
+	} else {
+		err = ErrWrongParamType(name, ParamValue, TypeAny, args[ParamValue])
+	}
+	return
+}
+
+func unsetFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
+	var varName string
+	var ok bool
+
+	if varName, ok = args[ParamName].(string); !ok {
+		return nil, ErrWrongParamType(name, ParamName, TypeString, args[ParamName])
+	} else {
+		ctx.GetParent().DeleteVar(varName)
+		result = nil
+	}
+	return
+}
+
 //// import
 
 func ImportBuiltinsFuncs(ctx ExprContext) {
@@ -240,6 +294,21 @@ func ImportBuiltinsFuncs(ctx ExprContext) {
 	ctx.RegisterFunc("eval", NewGolangFunctor(evalFunc), TypeAny, []ExprFuncParam{
 		NewFuncParam(ParamSource),
 	})
+
+	ctx.RegisterFunc("var", NewGolangFunctor(varFunc), TypeAny, []ExprFuncParam{
+		NewFuncParam(ParamName),
+		NewFuncParamFlagDef(ParamValue, PfDefault, nil),
+	})
+
+	ctx.RegisterFunc("set", NewGolangFunctor(setFunc), TypeAny, []ExprFuncParam{
+		NewFuncParam(ParamName),
+		NewFuncParam(ParamValue),
+	})
+
+	ctx.RegisterFunc("unset", NewGolangFunctor(unsetFunc), TypeAny, []ExprFuncParam{
+		NewFuncParam(ParamName),
+		NewFuncParam(ParamValue),
+	})
 }
 
 func init() {

builtin-iterator.go

@@ -23,9 +23,11 @@ func parseRunArgs(localCtx ExprContext, args map[string]any) (it Iterator, op Fu
 		return
 	}
 
-	if op, ok = args[iterParamOperator].(Functor); !ok && args[iterParamOperator] != nil {
-		err = fmt.Errorf("paramter %q must be a function, passed %v [%s]", iterParamOperator, args[iterParamOperator], TypeName(args[iterParamOperator]))
-		return
+	if args[iterParamOperator] != nil {
+		if op, ok = args[iterParamOperator].(Functor); !ok || op == nil {
+			err = fmt.Errorf("paramter %q must be a function, passed %v [%s]", iterParamOperator, args[iterParamOperator], TypeName(args[iterParamOperator]))
+			return
+		}
 	}
 
 	var vars *DictType
@@ -51,7 +53,7 @@ func runFunc(ctx ExprContext, name string, args map[string]any) (result any, err
 	var ok bool
 	var op Functor
 	var v any
-	var usingDefaultOp = false
+	// var usingDefaultOp = false
 	var params map[string]any
 	var item any
 
@@ -60,24 +62,27 @@ func runFunc(ctx ExprContext, name string, args map[string]any) (result any, err
 
 	if it, op, err = parseRunArgs(localCtx, args); err != nil {
 		return
-	} else if op == nil {
-		op = NewGolangFunctor(printLnFunc)
-		usingDefaultOp = true
+		// } else if op == nil {
+		// 	op = NewGolangFunctor(printLnFunc)
+		// 	usingDefaultOp = true
 	}
 
 	for item, err = it.Next(); err == nil; item, err = it.Next() {
-		if usingDefaultOp {
-			params = map[string]any{ParamItem: []any{item}}
-		} else {
-			params = map[string]any{ParamIndex: it.Index(), ParamItem: item}
-		}
+		// if usingDefaultOp {
+		// 	params = map[string]any{ParamItem: []any{item}}
+		// } else {
+		// params = map[string]any{ParamIndex: it.Index(), ParamItem: item}
+		// }
 
-		if v, err = op.InvokeNamed(localCtx, iterParamOperator, params); err != nil {
-			break
-		} else {
-			var success bool
-			if success, ok = ToBool(v); !success || !ok {
+		if op != nil {
+			params = map[string]any{ParamIndex: it.Index(), ParamItem: item}
+			if v, err = op.InvokeNamed(localCtx, iterParamOperator, params); err != nil {
 				break
+			} else {
+				var success bool
+				if success, ok = ToBool(v); !success || !ok {
+					break
+				}
 			}
 		}
 	}
@@ -86,6 +91,9 @@ func runFunc(ctx ExprContext, name string, args map[string]any) (result any, err
 		err = nil
 	}
 	if err == nil {
+		if op == nil {
+			ctx.UnsafeSetVar(iterVarStatus, it.Count())
+		}
 		result, _ = localCtx.GetVar(iterVarStatus)
 	}
 	return

builtin-os-file-iter.go

@@ -0,0 +1,149 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
+// builtin-os-file.go
+package expr
+
+import (
+	"fmt"
+	"io"
+	"slices"
+)
+
+const paramHandleOrPath = "handle-or-path"
+const fileReadTextIteratorType = "fileReadTextIterator"
+
+type fileReadTextIterator struct {
+	osReader  *osReader
+	index     int
+	count     int
+	line      string
+	autoClose bool
+}
+
+func newReadTextIterator(r *osReader, autoClose bool) *fileReadTextIterator {
+	return &fileReadTextIterator{osReader: r, index: -1, autoClose: autoClose}
+}
+
+func (it *fileReadTextIterator) TypeName() string {
+	return fileReadTextIteratorType
+}
+
+func (it *fileReadTextIterator) String() string {
+	if it.osReader != nil && it.osReader.fh != nil {
+		return fmt.Sprintf("$(%s@%q)", fileReadTextIteratorType, it.osReader.fh.Name())
+	}
+	return fmt.Sprintf("$(%s@<nil>)", fileReadTextIteratorType)
+}
+
+func (it *fileReadTextIterator) Count() int {
+	return it.count
+}
+
+func (it *fileReadTextIterator) Next() (item any, err error) { // must return io.EOF after the last item
+	if it.osReader.fh != nil {
+		if it.line, err = it.osReader.reader.ReadString('\n'); err == nil {
+			it.index++
+			it.count++
+			item = it.line[0 : len(it.line)-1]
+		} else if it.autoClose {
+			it.Clean()
+		}
+	}
+	return
+}
+
+func (it *fileReadTextIterator) Current() (item any, err error) {
+	if len(it.line) > 0 {
+		item = it.line[0 : len(it.line)-1]
+	}
+	return
+}
+
+func (it *fileReadTextIterator) Index() int {
+	return it.index
+}
+
+func (it *fileReadTextIterator) Reset() (err error) {
+	if _, err = it.osReader.fh.Seek(0, io.SeekStart); err == nil {
+		it.index = -1
+		it.count = 0
+		it.line = ""
+	}
+	return
+}
+
+func (it *fileReadTextIterator) HasOperation(name string) bool {
+	return slices.Contains([]string{NextName, ResetName, IndexName, CountName, CurrentName, CleanName}, name)
+}
+
+func (it *fileReadTextIterator) Clean() (err error) {
+	if it.osReader.fh != nil {
+		if err = it.osReader.fh.Close(); err == nil {
+			it.osReader = nil
+		}
+	}
+	return nil
+}
+
+func (it *fileReadTextIterator) CallOperation(name string, args map[string]any) (v any, err error) {
+	switch name {
+	case NextName:
+		v, err = it.Next()
+	case ResetName:
+		err = it.Reset()
+	case CleanName:
+		err = it.Clean()
+	case IndexName:
+		v = int64(it.Index())
+	case CurrentName:
+		v, err = it.Current()
+	case CountName:
+		v = it.count
+	default:
+		err = errNoOperation(name)
+	}
+	return
+}
+
+func fileReadIteratorFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
+	var handle *osReader
+	var invalidFileHandle any
+	var ok, autoClose bool
+
+	result = nil
+	if handle, ok = args[paramHandleOrPath].(*osReader); !ok {
+		if fileName, ok := args[paramHandleOrPath].(string); ok && len(fileName) > 0 {
+			var handleAny any
+			if handleAny, err = openFileFunc(ctx, name, map[string]any{ParamFilepath: fileName}); err != nil {
+				return
+			}
+			if handleAny != nil {
+				handle = handleAny.(*osReader)
+				autoClose = true
+			}
+		} else {
+			invalidFileHandle = args[paramHandleOrPath]
+		}
+	}
+
+	if handle != nil {
+		result = newReadTextIterator(handle, autoClose)
+
+	}
+
+	if err == nil && (handle == nil || invalidFileHandle != nil) {
+		err = errInvalidFileHandle(name, invalidFileHandle)
+	}
+	return
+}
+
+// func ImportOsIterFuncs(ctx ExprContext) {
+// 	ctx.RegisterFunc("fileReadIterator", NewGolangFunctor(fileReadIteratorFunc), TypeIterator, []ExprFuncParam{
+// 		NewFuncParam(paramHandleOrPath),
+// 	})
+// }
+
+// func init() {
+// 	RegisterBuiltinModule("os.file", ImportOsIterFuncs, "Operating system file iterator functions")
+// }

builtin-os-file.go

@@ -250,6 +250,10 @@ func ImportOsFuncs(ctx ExprContext) {
 	ctx.RegisterFunc("fileReadTextAll", NewGolangFunctor(fileReadTextAllFunc), TypeString, []ExprFuncParam{
 		NewFuncParam(ParamHandle),
 	})
+
+	ctx.RegisterFunc("fileReadIterator", NewGolangFunctor(fileReadIteratorFunc), TypeIterator, []ExprFuncParam{
+		NewFuncParam(paramHandleOrPath),
+	})
 }
 
 func init() {

builtin-string.go

@@ -200,6 +200,24 @@ func splitStrFunc(ctx ExprContext, name string, args map[string]any) (result any
 	return
 }
 
+func upperStrFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
+	if source, ok := args[ParamSource].(string); ok {
+		result = strings.ToUpper(source)
+	} else {
+		err = ErrWrongParamType(name, ParamSource, TypeString, args[ParamSource])
+	}
+	return
+}
+
+func lowerStrFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
+	if source, ok := args[ParamSource].(string); ok {
+		result = strings.ToLower(source)
+	} else {
+		err = ErrWrongParamType(name, ParamSource, TypeString, args[ParamSource])
+	}
+	return
+}
+
 // --- End of function definitions
 
 // Import above functions in the context
@@ -236,6 +254,14 @@ func ImportStringFuncs(ctx ExprContext) {
 		NewFuncParam(ParamSuffix),
 		NewFuncParamFlag(strParamOther, PfRepeat),
 	})
+
+	ctx.RegisterFunc("strUpper", NewGolangFunctor(upperStrFunc), TypeString, []ExprFuncParam{
+		NewFuncParam(ParamSource),
+	})
+
+	ctx.RegisterFunc("strLower", NewGolangFunctor(lowerStrFunc), TypeString, []ExprFuncParam{
+		NewFuncParam(ParamSource),
+	})
 }
 
 // Register the import function in the import-register.

common-errors.go

@@ -80,6 +80,10 @@ func ErrUnknownParam(funcName, paramName string) error {
 	return fmt.Errorf("%s(): unknown parameter %q", funcName, paramName)
 }
 
+func ErrUnknownVar(funcName, varName string) error {
+	return fmt.Errorf("%s(): unknown variable %q", funcName, varName)
+}
+
 // --- Operator errors
 
 func ErrLeftOperandMustBeVariable(leftTerm, opTerm *term) error {

common-type-names.go

@@ -13,6 +13,7 @@ const (
 	TypeFileHandle    = "file-handle"
 	TypeInt           = "integer"
 	TypeItem          = "item"
+	TypeIterator      = "iterator"
 	TypeNumber        = "number"
 	TypePair          = "pair"
 	TypeString        = "string"

dict-iterator.go

@@ -0,0 +1,221 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
+// dict-iterator.go
+package expr
+
+import (
+	"fmt"
+	"io"
+	"slices"
+	"strings"
+)
+
+type dictIterMode int
+
+const (
+	dictIterModeKeys dictIterMode = iota
+	dictIterModeValues
+	dictIterModeItems
+)
+
+type DictIterator struct {
+	a        *DictType
+	count    int
+	index    int
+	keys     []any
+	iterMode dictIterMode
+}
+
+type sortType int
+
+const (
+	sortTypeNone sortType = iota
+	sortTypeAsc
+	sortTypeDesc
+	sortTypeDefault = sortTypeAsc
+)
+
+func (it *DictIterator) makeKeys(m map[any]any, sort sortType) {
+	it.keys = make([]any, 0, len(m))
+
+	if sort == sortTypeNone {
+		for keyAny := range m {
+			it.keys = append(it.keys, keyAny)
+		}
+	} else {
+		scalarMap := make(map[string]any, len(m))
+		scalerKeys := make([]string, 0, len(m))
+		for keyAny := range m {
+			keyStr := fmt.Sprint(keyAny)
+			scalarMap[keyStr] = keyAny
+			scalerKeys = append(scalerKeys, keyStr)
+		}
+
+		switch sort {
+		case sortTypeAsc:
+			slices.Sort(scalerKeys)
+		case sortTypeDesc:
+			slices.Sort(scalerKeys)
+			slices.Reverse(scalerKeys)
+		}
+		for _, keyStr := range scalerKeys {
+			it.keys = append(it.keys, scalarMap[keyStr])
+		}
+	}
+}
+
+func NewDictIterator(dict *DictType, args []any) (it *DictIterator, err error) {
+	var sortType = sortTypeNone
+	var s string
+	var argAny any
+
+	dictIt := &DictIterator{a: dict, count: 0, index: -1, keys: nil, iterMode: dictIterModeKeys}
+	if len(args) > 0 {
+		argAny = args[0]
+	} else {
+		argAny = "default"
+	}
+	if s, err = ToGoString(argAny, "sort type"); err == nil {
+		switch strings.ToLower(s) {
+		case "a", "asc":
+			sortType = sortTypeAsc
+		case "d", "desc":
+			sortType = sortTypeDesc
+		case "n", "none", "nosort", "no-sort":
+			sortType = sortTypeNone
+		case "", "default":
+			sortType = sortTypeDefault
+		default:
+			err = fmt.Errorf("invalid sort type %q", s)
+		}
+
+		if err == nil {
+			if len(args) > 1 {
+				argAny = args[1]
+			} else {
+				argAny = "default"
+			}
+
+			if s, err = ToGoString(argAny, "iteration mode"); err == nil {
+				switch strings.ToLower(s) {
+				case "k", "key", "keys":
+					dictIt.iterMode = dictIterModeKeys
+				case "v", "value", "values":
+					dictIt.iterMode = dictIterModeValues
+				case "i", "item", "items":
+					dictIt.iterMode = dictIterModeItems
+				case "", "default":
+					dictIt.iterMode = dictIterModeKeys
+				default:
+					err = fmt.Errorf("invalid iteration mode %q", s)
+				}
+			}
+		}
+	}
+
+	dictIt.makeKeys(*dict, sortType)
+	return dictIt, err
+}
+
+func NewMapIterator(m map[any]any) (it *DictIterator) {
+	it = &DictIterator{a: (*DictType)(&m), count: 0, index: -1, keys: nil}
+	it.makeKeys(m, sortTypeNone)
+	return
+}
+
+func (it *DictIterator) String() string {
+	var l = 0
+	if it.a != nil {
+		l = len(*it.a)
+	}
+	return fmt.Sprintf("$({#%d})", l)
+}
+
+func (it *DictIterator) TypeName() string {
+	return "DictIterator"
+}
+
+func (it *DictIterator) HasOperation(name string) bool {
+	// yes := name == NextName || name == ResetName || name == IndexName || name == CountName || name == CurrentName
+	yes := slices.Contains([]string{NextName, ResetName, IndexName, CountName, CurrentName, CleanName, KeyName, ValueName}, name)
+	return yes
+}
+
+func (it *DictIterator) CallOperation(name string, args map[string]any) (v any, err error) {
+	switch name {
+	case NextName:
+		v, err = it.Next()
+	case ResetName:
+		err = it.Reset()
+	case CleanName:
+		err = it.Clean()
+	case IndexName:
+		v = int64(it.Index())
+	case CurrentName:
+		v, err = it.Current()
+	case CountName:
+		v = it.count
+	case KeyName:
+		if it.index >= 0 && it.index < len(it.keys) {
+			v = it.keys[it.index]
+		} else {
+			err = io.EOF
+		}
+	case ValueName:
+		if it.index >= 0 && it.index < len(it.keys) {
+			a := *(it.a)
+			v = a[it.keys[it.index]]
+		} else {
+			err = io.EOF
+		}
+	default:
+		err = errNoOperation(name)
+	}
+	return
+}
+
+func (it *DictIterator) Current() (item any, err error) {
+	if it.index >= 0 && it.index < len(it.keys) {
+		switch it.iterMode {
+		case dictIterModeKeys:
+			item = it.keys[it.index]
+		case dictIterModeValues:
+			a := *(it.a)
+			item = a[it.keys[it.index]]
+		case dictIterModeItems:
+			a := *(it.a)
+			pair := []any{it.keys[it.index], a[it.keys[it.index]]}
+			item = newList(pair)
+		}
+	} else {
+		err = io.EOF
+	}
+	return
+}
+
+func (it *DictIterator) Next() (item any, err error) {
+	it.index++
+	if item, err = it.Current(); err != io.EOF {
+		it.count++
+	}
+	return
+}
+
+func (it *DictIterator) Index() int {
+	return it.index
+}
+
+func (it *DictIterator) Count() int {
+	return it.count
+}
+
+func (it *DictIterator) Reset() error {
+	it.index = -1
+	it.count = 0
+	return nil
+}
+
+func (it *DictIterator) Clean() error {
+	return nil
+}

dict-type.go

@@ -33,7 +33,7 @@ func NewDict(dictAny map[any]any) (dict *DictType) {
 }
 
 func newDict(dictAny map[any]*term) (dict *DictType) {
-	// TODO Change wi a call to NewDict()
+	// TODO Change with a call to NewDict()
 	var d DictType
 	if dictAny != nil {
 		d = make(DictType, len(dictAny))

import-utils.go

@@ -76,6 +76,12 @@ func isFile(filePath string) bool {
 
 func searchAmongPath(filename string, dirList []string) (filePath string) {
 	var err error
+
+	suffix := SHAREDLIBRARY_EXTENSION
+	if strings.HasSuffix(filename, ".debug") {
+		suffix += ".debug"
+	}
+
 	for _, dir := range dirList {
 		if dir, err = ExpandPath(dir); err != nil {
 			continue
@@ -84,6 +90,12 @@ func searchAmongPath(filename string, dirList []string) (filePath string) {
 			filePath = fullPath
 			break
 		}
+
+		subdir := strings.TrimSuffix(filename, suffix)
+		if fullPath := path.Join(dir, subdir, filename); isFile(fullPath) {
+			filePath = fullPath
+			break
+		}
 	}
 	return
 }

iter-factory.go

@@ -0,0 +1,25 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
+// iter-factory.go
+package expr
+
+func NewIterator(value any) (it Iterator, err error) {
+	if value == nil {
+		return NewArrayIterator([]any{}), nil
+	}
+
+	switch v := value.(type) {
+	case *ListType:
+		it = NewListIterator(v, nil)
+	case *DictType:
+		it, err = NewDictIterator(v, nil)
+	case []any:
+		it = NewArrayIterator(v)
+	case Iterator:
+		it = v
+	default:
+		it = NewArrayIterator([]any{value})
+	}
+	return
+}

iterator.go

@@ -21,22 +21,25 @@ const (
 	CountName   = "count"
 	FilterName  = "filter"
 	MapName     = "map"
+	KeyName     = "key"
+	ValueName   = "value"
 )
 
 type Iterator interface {
 	Typer
+	fmt.Stringer
 	Next() (item any, err error) // must return io.EOF after the last item
 	Current() (item any, err error)
 	Index() int
 	Count() int
+	HasOperation(name string) bool
+	CallOperation(name string, args map[string]any) (value any, err error)
 }
 
 type ExtIterator interface {
 	Iterator
 	Reset() error
 	Clean() error
-	HasOperation(name string) bool
-	CallOperation(name string, args map[string]any) (value any, err error)
 }
 
 func errNoOperation(name string) error {

lib-ext-darwin.go

@@ -0,0 +1,9 @@
+//go:build darwin
+
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
+// lib-ext-darwin.go
+package expr
+
+const SHAREDLIBRARY_EXTENSION = ".dylib"

lib-ext-linux.go

@@ -0,0 +1,9 @@
+//go:build linux
+
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
+// lib-ext-linux.go
+package expr
+
+const SHAREDLIBRARY_EXTENSION = ".so"

lib-ext-windows.go

@@ -0,0 +1,9 @@
+//go:build windows
+
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
+// lib-ext-windows.go
+package expr
+
+const SHAREDLIBRARY_EXTENSION = ".dll"

list-iterator.go

@@ -62,27 +62,12 @@ func NewArrayIterator(array []any) (it *ListIterator) {
 	return
 }
 
-func NewAnyIterator(value any) (it *ListIterator) {
-	if value == nil {
-		it = NewArrayIterator([]any{})
-	} else if list, ok := value.(*ListType); ok {
-		it = NewListIterator(list, nil)
-	} else if array, ok := value.([]any); ok {
-		it = NewArrayIterator(array)
-	} else if it1, ok := value.(*ListIterator); ok {
-		it = it1
-	} else {
-		it = NewArrayIterator([]any{value})
-	}
-	return
-}
-
 func (it *ListIterator) String() string {
 	var l = 0
 	if it.a != nil {
 		l = len(*it.a)
 	}
-	return fmt.Sprintf("$(#%d)", l)
+	return fmt.Sprintf("$([#%d])", l)
 }
 
 func (it *ListIterator) TypeName() string {
@@ -149,12 +134,12 @@ func (it *ListIterator) Count() int {
 	return it.count
 }
 
-func (it *ListIterator) Reset() (error) {
+func (it *ListIterator) Reset() error {
 	it.index = it.start - it.step
 	it.count = 0
 	return nil
 }
 
-func (it *ListIterator) Clean() (error) {
+func (it *ListIterator) Clean() error {
 	return nil
 }

list-type.go

@@ -26,9 +26,9 @@ 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
 	}
@@ -53,14 +53,14 @@ func ListFromStrings(stringList []string) (list *ListType) {
 }
 
 func (ls *ListType) ToString(opt FmtOpt) (s string) {
-        indent := GetFormatIndent(opt)
-        flags := GetFormatFlags(opt)
+	indent := GetFormatIndent(opt)
+	flags := GetFormatFlags(opt)
 
 	var sb strings.Builder
 	sb.WriteByte('[')
 	if len(*ls) > 0 {
-                innerOpt := MakeFormatOptions(flags, indent+1)
-                nest := strings.Repeat("  ", indent+1)
+		innerOpt := MakeFormatOptions(flags, indent+1)
+		nest := strings.Repeat("  ", indent+1)
 
 		if flags&MultiLine != 0 {
 			sb.WriteByte('\n')
@@ -129,6 +129,20 @@ func (ls *ListType) contains(t *ListType) (answer bool) {
 	return
 }
 
+func (ls1 *ListType) Equals(ls2 ListType) (answer bool) {
+	if ls2 != nil && len(*ls1) == len(ls2) {
+		answer = true
+		for index, i1 := range *ls1 {
+			// if i1 != (ls2)[index] {
+			if reflect.DeepEqual(i1, ls2[index]) {
+				answer = false
+				break
+			}
+		}
+	}
+	return
+}
+
 func (list *ListType) indexDeepSameCmp(target any) (index int) {
 	var eq bool
 	var err error
@@ -193,3 +207,6 @@ func (list *ListType) setItem(index int64, value any) (err error) {
 	return
 }
 
+func (list *ListType) appendItem(value any) {
+	*list = append(*list, value)
+}

operand-iterator.go

@@ -86,37 +86,49 @@ func evalIterator(ctx ExprContext, opTerm *term) (v any, err error) {
 		return
 	}
 
-	if ds, err = getDataSourceDict(opTerm, firstChildValue); err != nil {
+	if ds, err = getDataSourceDict(opTerm, firstChildValue); err != nil && ds == nil {
 		return
 	}
+	err = nil
 
 	if ds != nil {
-		var dc *dataCursor
-		dcCtx := ctx.Clone()
-		if initFunc, exists := ds[InitName]; exists && initFunc != nil {
-			var args []any
-			var resource any
-			if len(opTerm.children) > 1 {
-				if args, err = evalTermArray(ctx, opTerm.children[1:]); err != nil {
+		if len(ds) > 0 {
+			var dc *dataCursor
+			dcCtx := ctx.Clone()
+			if initFunc, exists := ds[InitName]; exists && initFunc != nil {
+				var args []any
+				var resource any
+				if len(opTerm.children) > 1 {
+					if args, err = evalTermArray(ctx, opTerm.children[1:]); err != nil {
+						return
+					}
+				} else {
+					args = []any{}
+				}
+
+				actualParams := bindActualParams(initFunc, args)
+
+				initCtx := ctx.Clone()
+				if resource, err = initFunc.InvokeNamed(initCtx, InitName, actualParams); err != nil {
 					return
 				}
+				exportObjects(dcCtx, initCtx)
+				dc = NewDataCursor(dcCtx, ds, resource)
 			} else {
-				args = []any{}
+				dc = NewDataCursor(dcCtx, ds, nil)
 			}
 
-			actualParams := bindActualParams(initFunc, args)
-
-			initCtx := ctx.Clone()
-			if resource, err = initFunc.InvokeNamed(initCtx, InitName, actualParams); err != nil {
-				return
-			}
-			exportObjects(dcCtx, initCtx)
-			dc = NewDataCursor(dcCtx, ds, resource)
+			v = dc
 		} else {
-			dc = NewDataCursor(dcCtx, ds, nil)
+			if dictIt, ok := firstChildValue.(*DictType); ok {
+				var args []any
+				if args, err = evalSibling(ctx, opTerm.children, nil); err == nil {
+					v, err = NewDictIterator(dictIt, args)
+				}
+			} else {
+				err = opTerm.children[0].Errorf("the data-source must be a dictionary")
+			}
 		}
-
-		v = dc
 	} else if list, ok := firstChildValue.(*ListType); ok {
 		var args []any
 		if args, err = evalSibling(ctx, opTerm.children, nil); err == nil {

operator-assign.go

@@ -183,6 +183,16 @@ func evalOpAssign(ctx ExprContext, opTerm *term) (v any, err error) {
 				v, err = divValues(opTerm, leftValue, rightValue)
 			case SymPercEqual:
 				v, err = remainderValues(opTerm, leftValue, rightValue)
+			case SymAmpersandEqual:
+				v, err = bitwiseAnd(opTerm, leftValue, rightValue)
+			case SymVertBarEqual:
+				v, err = bitwiseOr(opTerm, leftValue, rightValue)
+			case SymCaretEqual:
+				v, err = bitwiseXor(opTerm, leftValue, rightValue)
+			case SymDoubleLessEqual:
+				v, err = bitLeftShift(opTerm, leftValue, rightValue)
+			case SymDoubleGreaterEqual:
+				v, err = bitRightShift(opTerm, leftValue, rightValue)
 			default:
 				err = opTerm.Errorf("unsupported assign operator %q", opTerm.source())
 			}
@@ -201,4 +211,10 @@ func init() {
 	registerTermConstructor(SymMinusEqual, newOpAssignTerm)
 	registerTermConstructor(SymStarEqual, newOpAssignTerm)
 	registerTermConstructor(SymSlashEqual, newOpAssignTerm)
+	registerTermConstructor(SymPercEqual, newOpAssignTerm)
+	registerTermConstructor(SymDoubleLessEqual, newOpAssignTerm)
+	registerTermConstructor(SymDoubleGreaterEqual, newOpAssignTerm)
+	registerTermConstructor(SymAmpersandEqual, newOpAssignTerm)
+	registerTermConstructor(SymVertBarEqual, newOpAssignTerm)
+	registerTermConstructor(SymCaretEqual, newOpAssignTerm)
 }

operator-binary.go

@@ -1,104 +0,0 @@
-// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
-
-// operator-binary.go
-package expr
-
-//-------- NOT term
-
-func newBinNotTerm(tk *Token) (inst *term) {
-	return &term{
-		tk:       *tk,
-		children: make([]*term, 0, 1),
-		position: posPrefix,
-		priority: priBinary,
-		evalFunc: evalBinaryNot,
-	}
-}
-
-func evalBinaryNot(ctx ExprContext, opTerm *term) (v any, err error) {
-	var value any
-
-	if value, err = opTerm.evalPrefix(ctx); err != nil {
-		return
-	}
-
-	if IsInteger(value) {
-		i, _ := value.(int64)
-		v = ^i
-	} else {
-		err = opTerm.errIncompatibleType(value)
-	}
-	return
-}
-
-//-------- Binary AND term
-
-func newBinAndTerm(tk *Token) (inst *term) {
-	return &term{
-		tk:       *tk,
-		children: make([]*term, 0, 2),
-		position: posInfix,
-		priority: priBinary,
-		evalFunc: evalBinaryAnd,
-	}
-}
-
-func evalBinaryAnd(ctx ExprContext, self *term) (v any, err error) {
-	var leftValue, rightValue any
-	var leftInt, rightInt int64
-	var lok, rok bool
-
-	if leftValue, rightValue, err = self.evalInfix(ctx); err != nil {
-		return
-	}
-
-	leftInt, lok = leftValue.(int64)
-	rightInt, rok = rightValue.(int64)
-
-	if lok && rok {
-		v = leftInt & rightInt
-	} else {
-		err = self.errIncompatibleTypes(leftValue, rightValue)
-	}
-	return
-}
-
-//-------- Binary OR term
-
-func newBinOrTerm(tk *Token) (inst *term) {
-	return &term{
-		tk:       *tk,
-		children: make([]*term, 0, 2),
-		position: posInfix,
-		priority: priBinary,
-		evalFunc: evalBinaryOr,
-	}
-}
-
-func evalBinaryOr(ctx ExprContext, self *term) (v any, err error) {
-	var leftValue, rightValue any
-	var leftInt, rightInt int64
-	var lok, rok bool
-
-	if leftValue, rightValue, err = self.evalInfix(ctx); err != nil {
-		return
-	}
-
-	leftInt, lok = leftValue.(int64)
-	rightInt, rok = rightValue.(int64)
-
-	if lok && rok {
-		v = leftInt | rightInt
-	} else {
-		err = self.errIncompatibleTypes(leftValue, rightValue)
-	}
-	return
-}
-
-// init
-func init() {
-	registerTermConstructor(SymTilde, newBinNotTerm)
-	registerTermConstructor(SymAmpersand, newBinAndTerm)
-	registerTermConstructor(SymVertBar, newBinOrTerm)
-}

operator-bitwise.go

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

operator-builtin.go

@@ -31,7 +31,10 @@ func evalBuiltin(ctx ExprContext, opTerm *term) (v any, err error) {
 		count, err = ImportInContextByGlobPattern(module)
 	} else {
 		var moduleSpec any
-		it := NewAnyIterator(childValue)
+		var it Iterator
+		if it, err = NewIterator(childValue); err != nil {
+			return
+		}
 		for moduleSpec, err = it.Next(); err == nil; moduleSpec, err = it.Next() {
 			if module, ok := moduleSpec.(string); ok {
 				if ImportInContext(module) {

operator-fraction.go

@@ -7,7 +7,6 @@ package expr
 //https://www.youmath.it/lezioni/algebra-elementare/lezioni-di-algebra-e-aritmetica-per-scuole-medie/553-dalle-frazioni-a-numeri-decimali.html
 
 import (
-	"errors"
 	"fmt"
 )
 
@@ -41,7 +40,7 @@ func evalFraction(ctx ExprContext, opTerm *term) (v any, err error) {
 		return
 	}
 	if den == 0 {
-		err = errors.New("division by zero")
+		err = opTerm.errDivisionByZero()
 		return
 	}
 

operator-insert.go

@@ -4,15 +4,15 @@
 // operator-insert.go
 package expr
 
-//-------- insert term
+//-------- prepend term
 
-func newInsertTerm(tk *Token) (inst *term) {
+func newPrependTerm(tk *Token) (inst *term) {
 	return &term{
 		tk:       *tk,
 		children: make([]*term, 0, 2),
 		position: posInfix,
-		priority: priAssign,
-		evalFunc: evalInsert,
+		priority: priInsert,
+		evalFunc: evalPrepend,
 	}
 }
 
@@ -21,12 +21,12 @@ func newAppendTerm(tk *Token) (inst *term) {
 		tk:       *tk,
 		children: make([]*term, 0, 2),
 		position: posInfix,
-		priority: priAssign,
+		priority: priInsert,
 		evalFunc: evalAppend,
 	}
 }
 
-func evalInsert(ctx ExprContext, opTerm *term) (v any, err error) {
+func evalPrepend(ctx ExprContext, opTerm *term) (v any, err error) {
 	var leftValue, rightValue any
 
 	if leftValue, rightValue, err = opTerm.evalInfix(ctx); err != nil {
@@ -40,10 +40,6 @@ func evalInsert(ctx ExprContext, opTerm *term) (v any, err error) {
 		if opTerm.children[1].symbol() == SymVariable {
 			ctx.UnsafeSetVar(opTerm.children[1].source(), v)
 		}
-	} else if IsInteger(leftValue) && IsInteger(rightValue) {
-		leftInt := leftValue.(int64)
-		rightInt := rightValue.(int64)
-		v = leftInt >> rightInt
 	} else {
 		err = opTerm.errIncompatibleTypes(leftValue, rightValue)
 	}
@@ -64,10 +60,6 @@ func evalAppend(ctx ExprContext, opTerm *term) (v any, err error) {
 		if opTerm.children[0].symbol() == SymVariable {
 			ctx.UnsafeSetVar(opTerm.children[0].source(), v)
 		}
-	} else if IsInteger(leftValue) && IsInteger(rightValue) {
-		leftInt := leftValue.(int64)
-		rightInt := rightValue.(int64)
-		v = leftInt << rightInt
 	} else {
 		err = opTerm.errIncompatibleTypes(leftValue, rightValue)
 	}
@@ -94,6 +86,6 @@ func evalAppend(ctx ExprContext, opTerm *term) (v any, err error) {
 
 // init
 func init() {
-	registerTermConstructor(SymInsert, newInsertTerm)
-	registerTermConstructor(SymAppend, newAppendTerm)
+	registerTermConstructor(SymPlusGreater, newPrependTerm)
+	registerTermConstructor(SymLessPlus, newAppendTerm)
 }

operator-iter-value.go

@@ -11,7 +11,7 @@ func newIterValueTerm(tk *Token) (inst *term) {
 		tk:       *tk,
 		children: make([]*term, 0, 1),
 		position: posPrefix,
-		priority: priIterValue,
+		priority: priDereference,
 		evalFunc: evalIterValue,
 	}
 }
@@ -33,6 +33,6 @@ func evalIterValue(ctx ExprContext, opTerm *term) (v any, err error) {
 
 // init
 func init() {
-//	registerTermConstructor(SymOpenClosedRound, newIterValueTerm)
-	registerTermConstructor(SymCaret, newIterValueTerm)
+	//	registerTermConstructor(SymOpenClosedRound, newIterValueTerm)
+	registerTermConstructor(SymDereference, newIterValueTerm)
 }

operator-map.go

@@ -0,0 +1,64 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
+// operator-map.go
+package expr
+
+import (
+	"fmt"
+	"io"
+)
+
+//-------- map term
+
+func newMapTerm(tk *Token) (inst *term) {
+	return &term{
+		tk:       *tk,
+		children: make([]*term, 0, 2),
+		position: posInfix,
+		priority: priIterOp,
+		evalFunc: evalMap,
+	}
+}
+
+func evalMap(ctx ExprContext, opTerm *term) (v any, err error) {
+	var leftValue, rightValue any
+	var it Iterator
+	var item any
+
+	if err = opTerm.checkOperands(); err != nil {
+		return
+	}
+
+	if leftValue, err = opTerm.children[0].compute(ctx); err != nil {
+		return
+	}
+
+	if it, err = NewIterator(leftValue); err != nil {
+		return nil, fmt.Errorf("left operand of MAP must be an iterable data-source; got %s", TypeName(leftValue))
+	}
+
+	values := newListA()
+	for item, err = it.Next(); err == nil; item, err = it.Next() {
+		ctx.SetVar("_", item)
+		ctx.SetVar("_index", it.Index())
+		ctx.SetVar("_count", it.Count())
+		if rightValue, err = opTerm.children[1].compute(ctx); err == nil {
+			values.appendItem(rightValue)
+		}
+		ctx.DeleteVar("_")
+		if err != nil {
+			break
+		}
+	}
+	if err == io.EOF {
+		err = nil
+	}
+	v = values
+	return
+}
+
+// init
+func init() {
+	registerTermConstructor(SymKwMap, newMapTerm)
+}

operator-post-inc-dec.go

@@ -1,7 +1,7 @@
 // Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
 // All rights reserved.
 
-// operator-post-inc.go
+// operator-post-inc-dec.go
 package expr
 
 // -------- post increment term
@@ -24,7 +24,27 @@ func evalPostInc(ctx ExprContext, opTerm *term) (v any, err error) {
 	}
 
 	if it, ok := childValue.(Iterator); ok {
+		var namePrefix string
 		v, err = it.Next()
+
+		if opTerm.children[0].symbol() == SymVariable {
+			namePrefix = opTerm.children[0].source()
+		}
+		ctx.UnsafeSetVar(namePrefix+"_index", it.Index())
+		if c, err1 := it.Current(); err1 == nil {
+			ctx.UnsafeSetVar(namePrefix+"_current", c)
+		}
+
+		if it.HasOperation(KeyName) {
+			if k, err1 := it.CallOperation(KeyName, nil); err1 == nil {
+				ctx.UnsafeSetVar(namePrefix+"_key", k)
+			}
+		}
+		if it.HasOperation(ValueName) {
+			if v1, err1 := it.CallOperation(ValueName, nil); err1 == nil {
+				ctx.UnsafeSetVar(namePrefix+"_value", v1)
+			}
+		}
 	} else if IsInteger(childValue) && opTerm.children[0].symbol() == SymVariable {
 		v = childValue
 		i, _ := childValue.(int64)

operator-pre-inc-dec.go

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

operator-prod.go

@@ -5,7 +5,6 @@
 package expr
 
 import (
-	"errors"
 	"strings"
 )
 
@@ -69,7 +68,7 @@ func divValues(opTerm *term, leftValue, rightValue any) (v any, err error) {
 		if IsFloat(leftValue) || IsFloat(rightValue) {
 			d := numAsFloat(rightValue)
 			if d == 0.0 {
-				err = errors.New("division by zero")
+				err = opTerm.errDivisionByZero()
 			} else {
 				v = numAsFloat(leftValue) / d
 			}
@@ -78,11 +77,36 @@ func divValues(opTerm *term, leftValue, rightValue any) (v any, err error) {
 		} else {
 			leftInt, _ := leftValue.(int64)
 			if rightInt, _ := rightValue.(int64); rightInt == 0 {
-				err = errors.New("division by zero")
+				err = opTerm.errDivisionByZero()
 			} else {
 				v = leftInt / rightInt
 			}
 		}
+	} else if IsString(leftValue) && IsString(rightValue) {
+		source := leftValue.(string)
+		sep := rightValue.(string)
+		v = ListFromStrings(strings.Split(source, sep))
+	} else if IsString(leftValue) && IsInteger(rightValue) {
+		source := leftValue.(string)
+		partSize := int(rightValue.(int64))
+		if partSize == 0 {
+			err = opTerm.errDivisionByZero()
+		} else {
+			partCount := len(source) / partSize
+			remainder := len(source) % partSize
+			listSize := partCount
+			if remainder > 0 {
+				listSize++
+			}
+			parts := make([]any, 0, listSize)
+			for i := 0; i < partCount; i++ {
+				parts = append(parts, source[i*partSize:(i+1)*partSize])
+			}
+			if remainder > 0 {
+				parts = append(parts, source[len(source)-remainder:])
+			}
+			v = newList(parts)
+		}
 	} else {
 		err = opTerm.errIncompatibleTypes(leftValue, rightValue)
 	}
@@ -121,7 +145,7 @@ func evalDivideAsFloat(ctx ExprContext, floatDivTerm *term) (v any, err error) {
 	if isNumOrFract(leftValue) && isNumOrFract(rightValue) {
 		d := numAsFloat(rightValue)
 		if d == 0.0 {
-			err = errors.New("division by zero")
+			err = floatDivTerm.errDivisionByZero()
 		} else {
 			v = numAsFloat(leftValue) / d
 		}
@@ -146,7 +170,7 @@ func remainderValues(opTerm *term, leftValue, rightValue any) (v any, err error)
 	if IsInteger(leftValue) && IsInteger(rightValue) {
 		rightInt, _ := rightValue.(int64)
 		if rightInt == 0 {
-			err = errors.New("division by zero")
+			err = opTerm.errDivisionByZero()
 		} else {
 			leftInt, _ := leftValue.(int64)
 			v = leftInt % rightInt

operator-shift.go

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

parser.go

@@ -409,6 +409,23 @@ func listSubTree(tree *ast, listTerm *term, allowIndeces bool) (root *term, err
 	return
 }
 
+func changePrefix(tk *Token) {
+	switch tk.Sym {
+	case SymMinus:
+		tk.SetSymbol(SymChangeSign)
+	case SymPlus:
+		tk.SetSymbol(SymUnchangeSign)
+	case SymStar:
+		tk.SetSymbol(SymDereference)
+	case SymExclamation:
+		tk.SetSymbol(SymNot)
+	case SymDoublePlus:
+		tk.SetSymbol(SymPreInc)
+	case SymDoubleMinus:
+		tk.SetSymbol(SymPreDec)
+	}
+}
+
 func (parser *parser) parseGeneral(scanner *scanner, ctx parserContext, termSymbols ...Symbol) (tree *ast, err error) {
 	var selectorTerm *term = nil
 	var currentTerm *term = nil
@@ -437,14 +454,16 @@ func (parser *parser) parseGeneral(scanner *scanner, ctx parserContext, termSymb
 
 		//fmt.Println("Token:", tk)
 		if firstToken {
-			if tk.Sym == SymMinus {
-				tk.Sym = SymChangeSign
-			} else if tk.Sym == SymPlus {
-				tk.Sym = SymUnchangeSign
-			} else if tk.IsSymbol(SymExclamation) {
-				err = tk.Errorf("postfix opertor %q requires an operand on its left", tk)
-				break
-			}
+			changePrefix(tk)
+			// if tk.Sym == SymMinus {
+			// 	tk.Sym = SymChangeSign
+			// } else if tk.Sym == SymPlus {
+			// 	tk.Sym = SymUnchangeSign
+			// } else if tk.IsSymbol(SymStar) {
+			// 	tk.SetSymbol(SymDereference)
+			// } else if tk.IsSymbol(SymExclamation) {
+			// 	tk.SetSymbol(SymNot)
+			// }
 			firstToken = false
 		}
 
@@ -452,9 +471,12 @@ func (parser *parser) parseGeneral(scanner *scanner, ctx parserContext, termSymb
 		case SymOpenRound:
 			var subTree *ast
 			if subTree, err = parser.parseGeneral(scanner, ctx, SymClosedRound); err == nil {
-				subTree.root.priority = priValue
-				err = tree.addTerm(newExprTerm(subTree.root))
-				currentTerm = subTree.root
+				exprTerm := newExprTerm(subTree.root)
+				err = tree.addTerm(exprTerm)
+				currentTerm = exprTerm
+				// subTree.root.priority = priValue
+				// err = tree.addTerm(newExprTerm(subTree.root))
+				// currentTerm = subTree.root
 			}
 		case SymFuncCall:
 			var funcCallTerm *term
@@ -478,7 +500,7 @@ func (parser *parser) parseGeneral(scanner *scanner, ctx parserContext, termSymb
 					currentTerm = mapTerm
 				}
 			}
-		case SymEqual, SymPlusEqual, SymMinusEqual, SymStarEqual, SymSlashEqual, SymPercEqual:
+		case SymEqual, SymPlusEqual, SymMinusEqual, SymStarEqual, SymSlashEqual, SymPercEqual, SymAmpersandEqual, SymVertBarEqual, SymDoubleLessEqual, SymDoubleGreaterEqual, SymCaretEqual:
 			currentTerm, err = tree.addToken(tk)
 			firstToken = true
 		case SymFuncDef:
@@ -515,14 +537,11 @@ func (parser *parser) parseGeneral(scanner *scanner, ctx parserContext, termSymb
 					}
 				}
 			} else {
-				// if hasFlag(ctx, allowIndex) {
-				// 	tk.Sym = SymRange
-				// }
 				currentTerm, err = tree.addToken(tk)
-			}
-			if tk.IsOneOfA(SymColon, SymRange) {
-				// Colon outside a selector term acts like a separator
-				firstToken = true
+				if tk.IsOneOfA(SymColon, SymRange) {
+					// Colon outside a selector term acts like a separator
+					firstToken = true
+				}
 			}
 		default:
 			currentTerm, err = tree.addToken(tk)

plugins.go

@@ -31,11 +31,11 @@ func pluginExists(name string) (exists bool) {
 func makePluginName(name string) (decorated string) {
 	var template string
 	if execName, err := os.Executable(); err != nil || !strings.Contains(execName, "debug") {
-		template = "expr-%s-plugin.so"
+		template = "expr-%s-plugin%s"
 	} else {
-		template = "expr-%s-plugin.so.debug"
+		template = "expr-%s-plugin%s.debug"
 	}
-	decorated = fmt.Sprintf(template, name)
+	decorated = fmt.Sprintf(template, name, SHAREDLIBRARY_EXTENSION)
 	return
 }
 
@@ -93,10 +93,12 @@ func importPlugin( /*ctx ExprContext,*/ dirList []string, name string) (err erro
 
 func importPluginFromSearchPath(name any) (count int, err error) {
 	var moduleSpec any
-
+	var it Iterator
 	dirList := buildSearchDirList("plugin", ENV_EXPR_PLUGIN_PATH)
 	count = 0
-	it := NewAnyIterator(name)
+	if it, err = NewIterator(name); err != nil {
+		return
+	}
 	for moduleSpec, err = it.Next(); err == nil; moduleSpec, err = it.Next() {
 		if module, ok := moduleSpec.(string); ok {
 			if err = importPlugin(dirList, module); err != nil {

scanner.go

@@ -124,6 +124,8 @@ func (scanner *scanner) fetchNextToken() (tk *Token) {
 				tk = scanner.moveOn(SymDoublePlus, ch, next)
 			} else if next == '=' {
 				tk = scanner.moveOn(SymPlusEqual, ch, next)
+			} else if next == '>' {
+				tk = scanner.moveOn(SymPlusGreater, ch, next)
 			} else {
 				tk = scanner.makeToken(SymPlus, ch)
 			}
@@ -167,13 +169,19 @@ func (scanner *scanner) fetchNextToken() (tk *Token) {
 		case '|':
 			if next, _ := scanner.peek(); next == '|' {
 				tk = scanner.moveOn(SymDoubleVertBar, ch, next)
+			} else if next, _ = scanner.peek(); next == '=' {
+				tk = scanner.moveOn(SymVertBarEqual, ch, next)
 			} else {
 				tk = scanner.makeToken(SymVertBar, ch)
 			}
 		case ',':
 			tk = scanner.makeToken(SymComma, ch)
 		case '^':
-			tk = scanner.makeToken(SymCaret, ch)
+			if next, _ := scanner.peek(); next == '=' {
+				tk = scanner.moveOn(SymCaretEqual, ch, next)
+			} else {
+				tk = scanner.makeToken(SymCaret, ch)
+			}
 		case ':':
 			if next, _ := scanner.peek(); next == ':' {
 				tk = scanner.moveOn(SymDoubleColon, ch, next)
@@ -202,14 +210,14 @@ func (scanner *scanner) fetchNextToken() (tk *Token) {
 				tk = scanner.makeToken(SymQuote, ch)
 				escape = false
 			} else {
-				tk = scanner.fetchString(ch)
+				tk = scanner.fetchString(ch, true)
 			}
 		case '"':
 			if escape {
 				tk = scanner.makeToken(SymDoubleQuote, ch)
 				escape = false
 			} else {
-				tk = scanner.fetchString(ch)
+				tk = scanner.fetchString(ch, true)
 			}
 		case '`':
 			tk = scanner.makeToken(SymBackTick, ch)
@@ -232,11 +240,17 @@ func (scanner *scanner) fetchNextToken() (tk *Token) {
 		case '&':
 			if next, _ := scanner.peek(); next == '&' {
 				tk = scanner.moveOn(SymDoubleAmpersand, ch, next)
+			} else if next, _ = scanner.peek(); next == '=' {
+				tk = scanner.moveOn(SymAmpersandEqual, ch, next)
 			} else {
 				tk = scanner.makeToken(SymAmpersand, ch)
 			}
 		case '%':
-			tk = scanner.makeToken(SymPercent, ch)
+			if next, _ := scanner.peek(); next == '=' {
+				tk = scanner.moveOn(SymPercEqual, ch, next)
+			} else {
+				tk = scanner.makeToken(SymPercent, ch)
+			}
 		case '#':
 			tk = scanner.makeToken(SymHash, ch)
 		case '@':
@@ -265,9 +279,18 @@ func (scanner *scanner) fetchNextToken() (tk *Token) {
 			if next, _ := scanner.peek(); next == '=' {
 				tk = scanner.moveOn(SymLessOrEqual, ch, next)
 			} else if next == '<' {
-				tk = scanner.moveOn(SymAppend, ch, next)
+				scanner.readChar()
+				next2, _ := scanner.readChar()
+				scanner.unreadChar()
+				if next2 == '=' {
+					tk = scanner.moveOn(SymDoubleLessEqual, ch, next, next2)
+				} else {
+					tk = scanner.accept(SymDoubleLess, ch, next)
+				}
 			} else if next == '>' {
 				tk = scanner.moveOn(SymLessGreater, ch, next)
+			} else if next == '+' {
+				tk = scanner.moveOn(SymLessPlus, ch, next)
 			} else {
 				tk = scanner.makeToken(SymLess, ch)
 			}
@@ -275,7 +298,14 @@ func (scanner *scanner) fetchNextToken() (tk *Token) {
 			if next, _ := scanner.peek(); next == '=' {
 				tk = scanner.moveOn(SymGreaterOrEqual, ch, next)
 			} else if next == '>' {
-				tk = scanner.moveOn(SymInsert, ch, next)
+				scanner.readChar()
+				next2, _ := scanner.readChar()
+				scanner.unreadChar()
+				if next2 == '=' {
+					tk = scanner.moveOn(SymDoubleGreaterEqual, ch, next, next2)
+				} else {
+					tk = scanner.accept(SymDoubleGreater, ch, next)
+				}
 			} else {
 				tk = scanner.makeToken(SymGreater, ch)
 			}
@@ -285,6 +315,14 @@ func (scanner *scanner) fetchNextToken() (tk *Token) {
 				tk.source += ")"
 			} else if next == '$' {
 				tk = scanner.moveOn(SymDoubleDollar, ch, next)
+			} else if next == '{' {
+				scanner.readChar()
+				if tk = scanner.fetchString('}', false); tk != nil {
+					tk.Sym = SymIdentifier
+				}
+			} else if next == '_' || (next >= 'a' && next <= 'z') || (next >= 'A' && next <= 'Z') {
+				scanner.readChar()
+				tk = scanner.fetchIdentifier(next)
 			} else {
 				tk = scanner.makeToken(SymDollar, ch)
 			}
@@ -560,7 +598,7 @@ func (scanner *scanner) fetchUntil(sym Symbol, allowEos bool, endings ...byte) (
 	return
 }
 
-func (scanner *scanner) fetchString(termCh byte) (tk *Token) {
+func (scanner *scanner) fetchString(termCh byte, addQuote bool) (tk *Token) {
 	var err error
 	var ch, prev byte
 	var sb strings.Builder
@@ -598,7 +636,11 @@ func (scanner *scanner) fetchString(termCh byte) (tk *Token) {
 		}
 	} else {
 		txt := sb.String()
-		tk = scanner.makeValueToken(SymString, `"`+txt+`"`, txt)
+		if addQuote {
+			tk = scanner.makeValueToken(SymString, `"`+txt+`"`, txt)
+		} else {
+			tk = scanner.makeValueToken(SymString, txt, txt)
+		}
 	}
 	return
 }
@@ -630,9 +672,16 @@ func (scanner *scanner) translate(sym Symbol) Symbol {
 
 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++ {
+	// for i := 1; i < len(chars); i++ {
+	if len(chars) > 1 {
 		scanner.readChar()
 	}
+	// }
+	return
+}
+
+func (scanner *scanner) accept(sym Symbol, chars ...byte) (tk *Token) {
+	tk = NewToken(scanner.row, scanner.column, scanner.translate(sym), string(chars))
 	return
 }
 

simple-store.go

@@ -24,6 +24,11 @@ func NewSimpleStore() *SimpleStore {
 	return ctx
 }
 
+func (ss *SimpleStore) Init() {
+	ss.varStore = make(map[string]any)
+	ss.funcStore = make(map[string]ExprFunc)
+}
+
 func filterRefName(name string) bool  { return name[0] != '@' }
 //func filterPrivName(name string) bool { return name[0] != '_' }
 

symbol-map.go

@@ -14,7 +14,7 @@ type symbolClass int16
 
 const (
 	symClassOperator symbolClass = iota
-	symClassPostOp
+	symClassCommand
 	symClassIdentifier
 	symClassDelimiter
 	symClassParenthesis
@@ -24,77 +24,87 @@ const (
 )
 
 type symbolSpec struct {
-	repr string
-	kind symbolClass
+	repr   string
+	kind   symbolClass
+	opType termPosition
 }
 
 func init() {
 
 	symbolMap = map[Symbol]symbolSpec{
-		SymUnknown:         {"<unknown>", symClassOther}, //  -1: Unknown symbol
-		SymNone:            {"<null>", symClassOther},    //   0: Null value for variable of type symbol
-		SymError:           {"<error>", symClassOther},   //   1: Error reading from stream
-		SymEos:             {"<eos>", symClassOther},     //   2: End of stream
-		SymMinus:           {"-", symClassOperator},      //   3: '-'
-		SymMinusEqual:      {"-=", symClassOperator},     //   4: '-='
-		SymDoubleMinus:     {"--", symClassOperator},     //   5: '--'
-		SymPlus:            {"+", symClassOperator},      //   6: '+'
-		SymPlusEqual:       {"+=", symClassOperator},     //   7: '+='
-		SymDoublePlus:      {"++", symClassOperator},     //   8: '++'
-		SymStar:            {"*", symClassOperator},      //   9: '*'
-		SymDoubleStar:      {"**", symClassOperator},     //  10: '**'
-		SymSlash:           {"/", symClassOperator},      //  11: '/'
-		SymBackSlash:       {"\\", symClassOperator},     //  12: '\'
-		SymVertBar:         {"|", symClassOperator},      //  13: '|'
-		SymDoubleVertBar:   {"||", symClassOperator},     //  14: '||'
-		SymComma:           {",", symClassOperator},      //  15: ','
-		SymColon:           {":", symClassOperator},      //  16: ':'
-		SymSemiColon:       {";", symClassOperator},      //  17: ';'
-		SymDot:             {".", symClassOperator},      //  18: '.'
-		SymDotSlash:        {"./", symClassOperator},     //  19: './'
-		SymQuote:           {"'", symClassDelimiter},     //  20: '\''
-		SymDoubleQuote:     {"\"", symClassDelimiter},    //  21: '"'
-		SymBackTick:        {"`", symClassOperator},      //  22: '`'
-		SymExclamation:     {"!", symClassPostOp},        //  23: '!'
-		SymQuestion:        {"?", symClassOperator},      //  24: '?'
-		SymAmpersand:       {"&", symClassOperator},      //  25: '&'
-		SymDoubleAmpersand: {"&&", symClassOperator},     //  26: '&&'
-		SymPercent:         {"%", symClassOperator},      //  27: '%'
-		SymAt:              {"@", symClassOperator},      //  28: '@'
-		SymUndescore:       {"_", symClassOperator},      //  29: '_'
-		SymEqual:           {"=", symClassOperator},      //  30: '='
-		SymDoubleEqual:     {"==", symClassOperator},     //  31: '=='
-		SymLess:            {"<", symClassOperator},      //  32: '<'
-		SymLessOrEqual:     {"<=", symClassOperator},     //  33: '<='
-		SymGreater:         {">", symClassOperator},      //  34: '>'
-		SymGreaterOrEqual:  {">=", symClassOperator},     //  35: '>='
-		SymLessGreater:     {"<>", symClassOperator},     //  36: '<>'
-		SymNotEqual:        {"!=", symClassOperator},     //  37: '!='
-		SymDollar:          {"$", symClassOperator},      //  38: '$'
-		SymHash:            {"#", symClassOperator},      //  39: '#'
-		SymOpenRound:       {"(", symClassParenthesis},   //  40: '('
-		SymClosedRound:     {")", symClassParenthesis},   //  41: ')'
-		SymOpenSquare:      {"[", symClassParenthesis},   //  42: '['
-		SymClosedSquare:    {"]", symClassParenthesis},   //  43: ']'
-		SymOpenBrace:       {"{", symClassParenthesis},   //  44: '{'
-		SymClosedBrace:     {"}", symClassParenthesis},   //  45: '}'
-		SymTilde:           {"~", symClassOperator},      //  46: '~'
-		SymDoubleQuestion:  {"??", symClassOperator},     //  47: '??'
-		SymQuestionEqual:   {"?=", symClassOperator},     //  48: '?='
-		SymQuestionExclam:  {"?!", symClassOperator},     //  49: '?!'
-		SymDoubleAt:        {"@@", symClassOperator},     //  50: '@@'
-		SymDoubleColon:     {"::", symClassOperator},     //  51: '::'
-		SymInsert:          {">>", symClassOperator},     //  52: '>>'
-		SymAppend:          {"<<", symClassOperator},     //  53: '<<'
-		SymCaret:           {"^", symClassOperator},      //  54: '^'
-		SymDollarRound:     {"$(", symClassOperator},     //  55: '$('
-		SymOpenClosedRound: {"()", symClassPostOp},       //  56: '()'
-		SymDoubleDollar:    {"$$", symClassOperator},     //  57: '$$'
-		SymDoubleDot:       {"..", symClassOperator},     //  58: '..'
-		SymTripleDot:       {"...", symClassOperator},    //  59: '...'
-		SymStarEqual:       {"*=", symClassOperator},     //  60: '*='
-		SymSlashEqual:      {"/=", symClassOperator},     //  61: '/='
-		SymPercEqual:       {"%=", symClassOperator},     //  62: '%='
+		SymUnknown:            {"<unknown>", symClassOther, posLeaf},  //  -1: Unknown symbol
+		SymNone:               {"<null>", symClassOther, posLeaf},     //   0: Null value for variable of type symbol
+		SymError:              {"<error>", symClassOther, posLeaf},    //   1: Error reading from stream
+		SymEos:                {"<eos>", symClassOther, posLeaf},      //   2: End of stream
+		SymMinus:              {"-", symClassOperator, posInfix},      //   3: '-'
+		SymMinusEqual:         {"-=", symClassOperator, posInfix},     //   4: '-='
+		SymDoubleMinus:        {"--", symClassOperator, posPostfix},   //   5: '--'
+		SymPlus:               {"+", symClassOperator, posInfix},      //   6: '+'
+		SymPlusEqual:          {"+=", symClassOperator, posInfix},     //   7: '+='
+		SymDoublePlus:         {"++", symClassOperator, posPostfix},   //   8: '++'
+		SymStar:               {"*", symClassOperator, posInfix},      //   9: '*'
+		SymDoubleStar:         {"**", symClassOperator, posInfix},     //  10: '**'
+		SymSlash:              {"/", symClassOperator, posInfix},      //  11: '/'
+		SymBackSlash:          {"\\", symClassOperator, posLeaf},      //  12: '\'
+		SymVertBar:            {"|", symClassOperator, posInfix},      //  13: '|'
+		SymDoubleVertBar:      {"||", symClassOperator, posInfix},     //  14: '||'
+		SymComma:              {",", symClassOperator, posInfix},      //  15: ','
+		SymColon:              {":", symClassOperator, posInfix},      //  16: ':'
+		SymSemiColon:          {";", symClassOperator, posInfix},      //  17: ';'
+		SymDot:                {".", symClassOperator, posInfix},      //  18: '.'
+		SymDotSlash:           {"./", symClassOperator, posInfix},     //  19: './'
+		SymQuote:              {"'", symClassDelimiter, posLeaf},      //  20: '\''
+		SymDoubleQuote:        {"\"", symClassDelimiter, posLeaf},     //  21: '"'
+		SymBackTick:           {"`", symClassDelimiter, posLeaf},      //  22: '`'
+		SymExclamation:        {"!", symClassOperator, posPostfix},    //  23: '!'
+		SymQuestion:           {"?", symClassOperator, posInfix},      //  24: '?'
+		SymAmpersand:          {"&", symClassOperator, posInfix},      //  25: '&'
+		SymDoubleAmpersand:    {"&&", symClassOperator, posInfix},     //  26: '&&'
+		SymPercent:            {"%", symClassOperator, posInfix},      //  27: '%'
+		SymAt:                 {"@", symClassOperator, posPrefix},     //  28: '@'
+		SymUndescore:          {"_", symClassIdentifier, posLeaf},     //  29: '_'
+		SymEqual:              {"=", symClassOperator, posInfix},      //  30: '='
+		SymDoubleEqual:        {"==", symClassOperator, posInfix},     //  31: '=='
+		SymLess:               {"<", symClassOperator, posInfix},      //  32: '<'
+		SymLessOrEqual:        {"<=", symClassOperator, posInfix},     //  33: '<='
+		SymGreater:            {">", symClassOperator, posInfix},      //  34: '>'
+		SymGreaterOrEqual:     {">=", symClassOperator, posInfix},     //  35: '>='
+		SymLessGreater:        {"<>", symClassOperator, posInfix},     //  36: '<>'
+		SymNotEqual:           {"!=", symClassOperator, posInfix},     //  37: '!='
+		SymDollar:             {"$", symClassOperator, posPrefix},     //  38: '$'
+		SymHash:               {"#", symClassOperator, posPrefix},     //  39: '#'
+		SymOpenRound:          {"(", symClassParenthesis, posPrefix},  //  40: '('
+		SymClosedRound:        {")", symClassParenthesis, posPostfix}, //  41: ')'
+		SymOpenSquare:         {"[", symClassParenthesis, posPrefix},  //  42: '['
+		SymClosedSquare:       {"]", symClassParenthesis, posPostfix}, //  43: ']'
+		SymOpenBrace:          {"{", symClassParenthesis, posPrefix},  //  44: '{'
+		SymClosedBrace:        {"}", symClassParenthesis, posPostfix}, //  45: '}'
+		SymTilde:              {"~", symClassOperator, posPrefix},     //  46: '~'
+		SymDoubleQuestion:     {"??", symClassOperator, posInfix},     //  47: '??'
+		SymQuestionEqual:      {"?=", symClassOperator, posInfix},     //  48: '?='
+		SymQuestionExclam:     {"?!", symClassOperator, posInfix},     //  49: '?!'
+		SymDoubleAt:           {"@@", symClassCommand, posLeaf},       //  50: '@@'
+		SymDoubleColon:        {"::", symClassOperator, posInfix},     //  51: '::'
+		SymDoubleGreater:      {">>", symClassOperator, posInfix},     //  52: '>>'
+		SymDoubleLess:         {"<<", symClassOperator, posInfix},     //  53: '<<'
+		SymCaret:              {"^", symClassOperator, posInfix},      //  54: '^'
+		SymDollarRound:        {"$(", symClassOperator, posPrefix},    //  55: '$('
+		SymOpenClosedRound:    {"()", symClassOperator, posPostfix},   //  56: '()'
+		SymDoubleDollar:       {"$$", symClassCommand, posLeaf},       //  57: '$$'
+		SymDoubleDot:          {"..", symClassOperator, posInfix},     //  58: '..'
+		SymTripleDot:          {"...", symClassOperator, posPostfix},  //  59: '...'
+		SymStarEqual:          {"*=", symClassOperator, posInfix},     //  60: '*='
+		SymSlashEqual:         {"/=", symClassOperator, posInfix},     //  61: '/='
+		SymPercEqual:          {"%=", symClassOperator, posInfix},     //  62: '%='
+		SymDoubleLessEqual:    {"<<=", symClassOperator, posInfix},    //  63: '<<='
+		SymDoubleGreaterEqual: {">>=", symClassOperator, posInfix},    //  64: '>>='
+		SymAmpersandEqual:     {"&=", symClassOperator, posInfix},     //  65: '&='
+		SymVertBarEqual:       {"|=", symClassOperator, posInfix},     //  65: '|='
+		SymCaretEqual:         {"^=", symClassOperator, posInfix},     //  66: '^='
+		SymPlusGreater:        {"+>", symClassOperator, posInfix},     //  67: '+>'
+		SymLessPlus:           {"<+", symClassOperator, posInfix},     //  68: '<+'
+		SymPreInc:             {"++", symClassOperator, posPrefix},    //    : '++'
+		SymPreDec:             {"--", symClassOperator, posPrefix},    //    : '--'
 		// SymChangeSign
 		// SymUnchangeSign
 		// SymIdentifier
@@ -121,17 +131,17 @@ func init() {
 		// // SymClosedComment                     //   0: '*/'
 		// // SymOneLineComment                    //   0: '//'
 		// keywordBase
-		SymKwAnd:     {"and", symClassOperator},
-		SymKwNot:     {"not", symClassOperator},
-		SymKwOr:      {"or", symClassOperator},
-		SymKwBut:     {"but", symClassOperator},
-		SymKwFunc:    {"func(", symClassDeclaration},
-		SymKwBuiltin: {"builtin", symClassOperator},
-		SymKwPlugin:  {"plugin", symClassOperator},
-		SymKwIn:      {"in", symClassOperator},
-		SymKwInclude: {"include", symClassOperator},
-		SymKwNil:     {"nil", symClassValue},
-		SymKwUnset:   {"unset", symClassOperator},
+		SymKwAnd:     {"and", symClassOperator, posInfix},
+		SymKwNot:     {"not", symClassOperator, posInfix},
+		SymKwOr:      {"or", symClassOperator, posInfix},
+		SymKwBut:     {"but", symClassOperator, posInfix},
+		SymKwFunc:    {"func(", symClassDeclaration, posPrefix},
+		SymKwBuiltin: {"builtin", symClassOperator, posPrefix},
+		SymKwPlugin:  {"plugin", symClassOperator, posPrefix},
+		SymKwIn:      {"in", symClassOperator, posInfix},
+		SymKwInclude: {"include", symClassOperator, posPrefix},
+		SymKwNil:     {"nil", symClassValue, posLeaf},
+		SymKwUnset:   {"unset", symClassOperator, posPrefix},
 	}
 }
 
@@ -169,12 +179,19 @@ func StringEndsWithOperator(s string) bool {
 }
 
 func endingOperator(s string) (sym Symbol) {
+	var matchLength = 0
 	sym = SymNone
-	lower := strings.ToLower(s)
+	lower := strings.TrimRight(strings.ToLower(s), " \t")
 	for symbol, spec := range symbolMap {
-		if spec.kind == symClassOperator && strings.HasSuffix(lower, spec.repr) {
-			sym = symbol
-			break
+		if strings.HasSuffix(lower, spec.repr) {
+			if len(spec.repr) > matchLength {
+				matchLength = len(spec.repr)
+				if spec.kind == symClassOperator && (spec.opType == posInfix || spec.opType == posPrefix) {
+					sym = symbol
+				} else {
+					sym = SymNone
+				}
+			}
 		}
 	}
 	return

symbol.go

@@ -7,72 +7,82 @@ package expr
 type Symbol int16
 
 const (
-	SymUnknown         Symbol = iota - 1 //  -1: Unknown symbol
-	SymNone                              //   0: Null value for variable of type symbol
-	SymError                             //   1: Error reading from stream
-	SymEos                               //   2: End of stream
-	SymMinus                             //   3: '-'
-	SymMinusEqual                        //   4: '-='
-	SymDoubleMinus                       //   5: '--'
-	SymPlus                              //   6: '+'
-	SymPlusEqual                         //   7: '+='
-	SymDoublePlus                        //   8: '++'
-	SymStar                              //   9: '*'
-	SymDoubleStar                        //  10: '**'
-	SymSlash                             //  11: '/'
-	SymBackSlash                         //  12: '\'
-	SymVertBar                           //  13: '|'
-	SymDoubleVertBar                     //  14: '||'
-	SymComma                             //  15: ','
-	SymColon                             //  16: ':'
-	SymSemiColon                         //  17: ';'
-	SymDot                               //  18: '.'
-	SymDotSlash                          //  19: './'
-	SymQuote                             //  20: '\''
-	SymDoubleQuote                       //  21: '"'
-	SymBackTick                          //  22: '`'
-	SymExclamation                       //  23: '!'
-	SymQuestion                          //  24: '?'
-	SymAmpersand                         //  25: '&'
-	SymDoubleAmpersand                   //  26: '&&'
-	SymPercent                           //  27: '%'
-	SymAt                                //  28: '@'
-	SymUndescore                         //  29: '_'
-	SymEqual                             //  30: '='
-	SymDoubleEqual                       //  31: '=='
-	SymLess                              //  32: '<'
-	SymLessOrEqual                       //  33: '<='
-	SymGreater                           //  34: '>'
-	SymGreaterOrEqual                    //  35: '>='
-	SymLessGreater                       //  36: '<>'
-	SymNotEqual                          //  37: '!='
-	SymDollar                            //  38: '$'
-	SymHash                              //  39: '#'
-	SymOpenRound                         //  40: '('
-	SymClosedRound                       //  41: ')'
-	SymOpenSquare                        //  42: '['
-	SymClosedSquare                      //  43: ']'
-	SymOpenBrace                         //  44: '{'
-	SymClosedBrace                       //  45: '}'
-	SymTilde                             //  46: '~'
-	SymDoubleQuestion                    //  47: '??'
-	SymQuestionEqual                     //  48: '?='
-	SymQuestionExclam                    //  49: '?!'
-	SymDoubleAt                          //  50: '@@'
-	SymDoubleColon                       //  51: '::'
-	SymInsert                            //  52: '>>'
-	SymAppend                            //  53: '<<'
-	SymCaret                             //  54: '^'
-	SymDollarRound                       //  55: '$('
-	SymOpenClosedRound                   //  56: '()'
-	SymDoubleDollar                      //  57: '$$'
-	SymDoubleDot                         //  58: '..'
-	SymTripleDot                         //  59: '...'
-	SymStarEqual                         //  60: '*='
-	SymSlashEqual                        //  61: '/='
-	SymPercEqual                         //  62: '%='
+	SymUnknown            Symbol = iota - 1 //  -1: Unknown symbol
+	SymNone                                 //   0: Null value for variable of type symbol
+	SymError                                //   1: Error reading from stream
+	SymEos                                  //   2: End of stream
+	SymMinus                                //   3: '-'
+	SymMinusEqual                           //   4: '-='
+	SymDoubleMinus                          //   5: '--'
+	SymPlus                                 //   6: '+'
+	SymPlusEqual                            //   7: '+='
+	SymDoublePlus                           //   8: '++'
+	SymStar                                 //   9: '*'
+	SymDoubleStar                           //  10: '**'
+	SymSlash                                //  11: '/'
+	SymBackSlash                            //  12: '\'
+	SymVertBar                              //  13: '|'
+	SymDoubleVertBar                        //  14: '||'
+	SymComma                                //  15: ','
+	SymColon                                //  16: ':'
+	SymSemiColon                            //  17: ';'
+	SymDot                                  //  18: '.'
+	SymDotSlash                             //  19: './'
+	SymQuote                                //  20: '\''
+	SymDoubleQuote                          //  21: '"'
+	SymBackTick                             //  22: '`'
+	SymExclamation                          //  23: '!'
+	SymQuestion                             //  24: '?'
+	SymAmpersand                            //  25: '&'
+	SymDoubleAmpersand                      //  26: '&&'
+	SymPercent                              //  27: '%'
+	SymAt                                   //  28: '@'
+	SymUndescore                            //  29: '_'
+	SymEqual                                //  30: '='
+	SymDoubleEqual                          //  31: '=='
+	SymLess                                 //  32: '<'
+	SymLessOrEqual                          //  33: '<='
+	SymGreater                              //  34: '>'
+	SymGreaterOrEqual                       //  35: '>='
+	SymLessGreater                          //  36: '<>'
+	SymNotEqual                             //  37: '!='
+	SymDollar                               //  38: '$'
+	SymHash                                 //  39: '#'
+	SymOpenRound                            //  40: '('
+	SymClosedRound                          //  41: ')'
+	SymOpenSquare                           //  42: '['
+	SymClosedSquare                         //  43: ']'
+	SymOpenBrace                            //  44: '{'
+	SymClosedBrace                          //  45: '}'
+	SymTilde                                //  46: '~'
+	SymDoubleQuestion                       //  47: '??'
+	SymQuestionEqual                        //  48: '?='
+	SymQuestionExclam                       //  49: '?!'
+	SymDoubleAt                             //  50: '@@'
+	SymDoubleColon                          //  51: '::'
+	SymDoubleGreater                        //  52: '>>'
+	SymDoubleLess                           //  53: '<<'
+	SymCaret                                //  54: '^'
+	SymDollarRound                          //  55: '$('
+	SymOpenClosedRound                      //  56: '()'
+	SymDoubleDollar                         //  57: '$$'
+	SymDoubleDot                            //  58: '..'
+	SymTripleDot                            //  59: '...'
+	SymStarEqual                            //  60: '*='
+	SymSlashEqual                           //  61: '/='
+	SymPercEqual                            //  62: '%='
+	SymDoubleLessEqual                      //  63: '<<='
+	SymDoubleGreaterEqual                   //  64: '>>='
+	SymAmpersandEqual                       //  65: '&='
+	SymVertBarEqual                         //  65: '|='
+	SymCaretEqual                           //  66: '^='
+	SymPlusGreater                          //  67: '+>'
+	SymLessPlus                             //  68: '<+'
 	SymChangeSign
 	SymUnchangeSign
+	SymDereference
+	SymPreInc
+	SymPreDec
 	SymIdentifier
 	SymBool
 	SymInteger
@@ -109,6 +119,7 @@ const (
 	SymKwPlugin
 	SymKwIn
 	SymKwInclude
+	SymKwMap
 	SymKwNil
 	SymKwUnset
 )
@@ -125,6 +136,7 @@ func init() {
 		"FUNC":    SymKwFunc,
 		"IN":      SymKwIn,
 		"INCLUDE": SymKwInclude,
+		"MAP":     SymKwMap,
 		"NOT":     SymKwNot,
 		"OR":      SymKwOr,
 		"NIL":     SymKwNil,

t_bool_test.go

@@ -26,12 +26,13 @@ func TestBool(t *testing.T) {
 		/*  12 */ {`true or false`, true, nil},
 		/*  13 */ {`true or []`, true, nil},
 		/*  14 */ {`[] or false`, nil, errors.New(`got list as left operand type of 'OR' operator, it must be bool`)},
+		/*  15 */ {`!true`, false, nil},
 		/*  13 */ //{`true or []`, nil, errors.New(`[1:8] left operand 'true' [bool] and right operand '[]' [list] are not compatible with operator "OR"`)},
 	}
 
 	// t.Setenv("EXPR_PATH", ".")
 
-	// runTestSuiteSpec(t, section, inputs, 1)
+	// runTestSuiteSpec(t, section, inputs, 15)
 	runTestSuite(t, section, inputs)
 }
 

t_builtin-base_test.go

@@ -52,16 +52,21 @@ func TestFuncBase(t *testing.T) {
 		/*  38 */ {`bool(1.0)`, true, nil},
 		/*  39 */ {`bool("1")`, true, nil},
 		/*  40 */ {`bool(false)`, false, nil},
-		/*  41 */ {`bool([1])`, nil, `bool(): can't convert list to bool`},
-		/*  42 */ {`dec(false)`, float64(0), nil},
-		/*  43 */ {`dec(1:2)`, float64(0.5), nil},
-		/*  44 */ {`dec([1])`, nil, `dec(): can't convert list to float`},
-		/*  45 */ {`eval("a=3"); a`, int64(3), nil},
+		/*  41 */ {`bool([1])`, true, nil},
+		/*  42 */ {`bool([])`, false, nil},
+		/*  43 */ {`bool({})`, false, nil},
+		/*  44 */ {`bool({1:"one"})`, true, nil},
+		/*  45 */ {`dec(false)`, float64(0), nil},
+		/*  46 */ {`dec(1:2)`, float64(0.5), nil},
+		/*  47 */ {`dec([1])`, nil, `dec(): can't convert list to float`},
+		/*  48 */ {`eval("a=3"); a`, int64(3), nil},
+		/*  49 */ {`int(5:2)`, int64(2), nil},
+
 		// /*  45 */ {`string([1])`, nil, `string(): can't convert list to string`},
 	}
 
 	t.Setenv("EXPR_PATH", ".")
 
-	// runTestSuiteSpec(t, section, inputs, 45)
+	// runTestSuiteSpec(t, section, inputs, 49)
 	runTestSuite(t, section, inputs)
 }

t_builtin-iterator_test.go

@@ -21,10 +21,11 @@ func TestFuncRun(t *testing.T) {
 		/*   7 */ {`builtin "iterator"; run($(1,2,3), func(){1}, "prrr")`, nil, `paramter "vars" must be a dictionary, passed prrr [string]`},
 		/*   8 */ {`builtin "iterator"; run($(1,2,3), operator=nil)`, nil, nil},
 		/*   9 */ {`builtin "iterator"; run($(1,2,3), operatorx=nil)`, nil, `run(): unknown param "operatorx"`},
+		/*   10 */ {`builtin ["os.file", "iterator"]; it = fileReadIterator("test-file.txt"); run(it)`, nil, nil},
 	}
 
 	//t.Setenv("EXPR_PATH", ".")
 
-	//runTestSuiteSpec(t, section, inputs, 1)
-	runTestSuite(t, section, inputs)
+	runTestSuiteSpec(t, section, inputs, 10)
+	// runTestSuite(t, section, inputs)
 }

t_builtin-os-file_test.go

@@ -5,6 +5,7 @@
 package expr
 
 import (
+	"io"
 	"testing"
 )
 
@@ -26,10 +27,13 @@ func TestFuncOs(t *testing.T) {
 		/*  13 */ {`builtin "os.file"; handle=fileClose(123)`, nil, `fileClose(): invalid file handle`},
 		/*  14 */ {`builtin "os.file"; handle=fileOpen("/tmp/dummy"); c=fileReadTextAll(handle); fileClose(handle); c`, "bye-bye", nil},
 		/*  15 */ {`builtin "os.file"; c=fileReadTextAll(123)`, nil, `fileReadTextAll(): invalid file handle 123 [int64]`},
+		/*  16 */ {`builtin "os.file"; it=fileReadIterator("test-file.txt"); it++`, "uno", nil},
+		/*  17 */ {`builtin "os.file"; it=fileReadIterator("test-file.txt"); it++;it++;it++`, nil, io.EOF.Error()},
+		/*  18 */ {`builtin "os.file"; it=fileReadIterator("test-file.txt"); it.clean`, nil, nil},
 	}
 
 	// t.Setenv("EXPR_PATH", ".")
 
-	//runTestSuiteSpec(t, section, inputs, 2)
-	runTestSuite(t, section, inputs)
+	runTestSuiteSpec(t, section, inputs, 18)
+	// runTestSuite(t, section, inputs)
 }

t_builtin-string_test.go

@@ -31,6 +31,8 @@ func TestFuncString(t *testing.T) {
 		/*  17 */ {`builtin "string"; strSplit("one-two-three", "-")`, newListA("one", "two", "three"), nil},
 		/*  18 */ {`builtin "string"; strJoin("-", [1, "two", "three"])`, nil, `strJoin(): expected string, got integer (1)`},
 		/*  19 */ {`builtin "string"; strJoin()`, nil, `strJoin(): too few params -- expected 1 or more, got 0`},
+		/*  20 */ {`builtin "string"; strUpper("StOp")`, "STOP", nil},
+		/*  21 */ {`builtin "string"; strLower("StOp")`, "stop", nil},
 
 		/*  69 */ /*{`builtin "string"; $$global`, `vars: {
 		}

t_common_test.go

@@ -72,6 +72,7 @@ func doTest(t *testing.T, ctx ExprContext, section string, input *inputType, cou
 	var expr Expr
 	var gotResult any
 	var gotErr error
+	var eq, eqDone bool
 
 	wantErr := getWantedError(input)
 
@@ -90,7 +91,18 @@ func doTest(t *testing.T, ctx ExprContext, section string, input *inputType, cou
 		gotResult, gotErr = expr.Eval(ctx)
 	}
 
-	eq := reflect.DeepEqual(gotResult, input.wantResult)
+	if input.wantResult != nil && gotResult != nil {
+		if ls1, ok := input.wantResult.(*ListType); ok {
+			if ls2, ok := gotResult.(*ListType); ok {
+				eq = ls1.Equals(*ls2)
+				eqDone = true
+			}
+		}
+	}
+
+	if !eqDone {
+		eq = reflect.DeepEqual(gotResult, input.wantResult)
+	}
 
 	if !eq /*gotResult != input.wantResult*/ {
 		t.Errorf("%d: `%s` -> result = %v [%s], want = %v [%s]", count, input.source, gotResult, TypeName(gotResult), input.wantResult, TypeName(input.wantResult))

t_expr_test.go

@@ -29,7 +29,9 @@ func TestExpr(t *testing.T) {
 		/*  15 */ {`a=3; a*=2)+1; a`, nil, `[1:11] unexpected token ")"`},
 		/*  16 */ {`v=[2]; a=1; v[a-=1]=5; v[0]`, int64(5), nil},
 		/*  17 */ {`true ? {"a"} :: {"b"}`, "a", nil},
-		/*  18 */ {`
+		/*  18 */ {`$$`, NewDict(map[any]any{"variables": NewDict(nil), "functions": NewDict(nil)}), nil},
+		///*  19 */ {`$$global`, NewDict(map[any]any{"variables": NewDict(nil), "functions": NewDict(nil)}), nil},
+		/*  19 */ {`
 		ds={
 			"init":func(@end){@current=0 but true},
 			//"current":func(){current},
@@ -41,9 +43,11 @@ func TestExpr(t *testing.T) {
 		it++;
 		it++
 `, int64(1), nil},
+		/*  20 */ {`a=2; ${a}`, int64(2), nil},
+		/*  21 */ {`$_=2; $_`, int64(2), nil},
 	}
 	// t.Setenv("EXPR_PATH", ".")
 
-	// runTestSuiteSpec(t, section, inputs, 6, 7, 8, 9)
+	// runTestSuiteSpec(t, section, inputs, 21)
 	runTestSuite(t, section, inputs)
 }

t_fractions_test.go

@@ -25,7 +25,7 @@ func TestFractionsParser(t *testing.T) {
 		/*  12 */ {`builtin "math.arith"; add(1:2, 1.0, 2)`, float64(3.5), nil},
 		/*  13 */ {`builtin "math.arith"; mul(1:2, 2:3)`, newFraction(2, 6), nil},
 		/*  14 */ {`builtin "math.arith"; mul(1:2, 1.0, 2)`, float64(1.0), nil},
-		/*  15 */ {`1:0`, nil, `division by zero`},
+		/*  15 */ {`1:0`, nil, `[1:3] division by zero`},
 		/*  16 */ {`fract(-0.5)`, newFraction(-1, 2), nil},
 		/*  17 */ {`fract("")`, (*FractionType)(nil), `bad syntax`},
 		/*  18 */ {`fract("-1")`, newFraction(-1, 1), nil},
@@ -34,7 +34,7 @@ func TestFractionsParser(t *testing.T) {
 		/*  21 */ {`fract(1,0)`, nil, `fract(): division by zero`},
 		/*  22 */ {`string(1:2)`, "1:2", nil},
 		/*  23 */ {`1+1:2+0.5`, float64(2), nil},
-		/*  24 */ {`1:(2-2)`, nil, `division by zero`},
+		/*  24 */ {`1:(2-2)`, nil, `[1:3] division by zero`},
 		/*  25 */ {`[0,1][1-1]:1`, newFraction(0, 1), nil},
 	}
 	// runTestSuiteSpec(t, section, inputs, 25)

t_funcs_test.go

@@ -68,3 +68,27 @@ func TestFunctionGetFunc(t *testing.T) {
 		t.Errorf(`(func() -> result = %v [%T], want = %v [%T]`, got, got, want, want)
 	}
 }
+
+func TestGoFunction(t *testing.T) {
+	section := "Funcs"
+	inputs := []inputType{
+		/*   1 */ {`myName()`, "Celestino Amoroso", nil},
+		/*   2 */ {`myName("Peppino")`, "Peppino", nil},
+	}
+
+	myName := func(ctx ExprContext, name string, args map[string]any) (result any, err error) {
+		var ok bool
+		if result, ok = args["name"].(string); !ok {
+			err = ErrWrongParamType(name, "name", TypeString, args["name"])
+		}
+		return
+	}
+
+	ctx := NewSimpleStore()
+	ctx.RegisterFunc("myName", NewGolangFunctor(myName), TypeString, []ExprFuncParam{
+		NewFuncParamFlagDef("name", PfOptional|PfDefault, "Celestino Amoroso"),
+	})
+
+	runCtxTestSuite(t, ctx, section, inputs)
+
+}

t_iter-list_test.go

@@ -59,7 +59,7 @@ func TestNewIterList2(t *testing.T) {
 
 func TestNewIterList3(t *testing.T) {
 	list := []any{"a", "b", "c", "d"}
-	it := NewAnyIterator(list)
+	it, _ := NewIterator(list)
 	if item, err := it.Next(); err != nil {
 		t.Errorf("error: %v", err)
 	} else if item != "a" {
@@ -71,7 +71,7 @@ func TestNewIterList3(t *testing.T) {
 
 func TestNewIterList4(t *testing.T) {
 	list := any(nil)
-	it := NewAnyIterator(list)
+	it, _ := NewIterator(list)
 	if _, err := it.Next(); err != io.EOF {
 		t.Errorf("error: %v", err)
 	}
@@ -79,7 +79,7 @@ func TestNewIterList4(t *testing.T) {
 
 func TestNewIterList5(t *testing.T) {
 	list := "123"
-	it := NewAnyIterator(list)
+	it, _ := NewIterator(list)
 	if item, err := it.Next(); err != nil {
 		t.Errorf("error: %v", err)
 	} else if item != "123" {
@@ -91,8 +91,8 @@ func TestNewIterList5(t *testing.T) {
 
 func TestNewIterList6(t *testing.T) {
 	list := newListA("a", "b", "c", "d")
-	it1 := NewAnyIterator(list)
-	it := NewAnyIterator(it1)
+	it1, _ := NewIterator(list)
+	it, _ := NewIterator(it1)
 	if item, err := it.Next(); err != nil {
 		t.Errorf("error: %v", err)
 	} else if item != "a" {
@@ -103,9 +103,9 @@ func TestNewIterList6(t *testing.T) {
 }
 func TestNewString(t *testing.T) {
 	list := "123"
-	it := NewAnyIterator(list)
-	if s := it.String(); s != "$(#1)" {
-		t.Errorf("expected $(#1), got %s", s)
+	it, _ := NewIterator(list)
+	if s := it.String(); s != "$([#1])" {
+		t.Errorf("expected $([#1]), got %s", s)
 	}
 }
 

t_iterator_test.go

@@ -9,10 +9,10 @@ import "testing"
 func TestIteratorParser(t *testing.T) {
 	section := "Iterator"
 	inputs := []inputType{
-		/*   1 */ {`include "test-resources/iterator.expr"; it=$(ds,3); ^it`, int64(0), nil},
+		/*   1 */ {`include "test-resources/iterator.expr"; it=$(ds,3); *it`, int64(0), nil},
 		/*   2 */ {`include "test-resources/iterator.expr"; it=$(ds,3); it++; it++`, int64(1), nil},
 		/*   3 */ {`include "test-resources/iterator.expr"; it=$(ds,3); it++; it++; #it`, int64(3), nil},
-		/*   4 */ {`include "test-resources/iterator.expr"; it=$(ds,3); it++; it++; it.reset; ^it`, int64(0), nil},
+		/*   4 */ {`include "test-resources/iterator.expr"; it=$(ds,3); it++; it++; it.reset; *it`, int64(0), nil},
 		/*   5 */ {`builtin "math.arith"; include "test-resources/iterator.expr"; it=$(ds,3); add(it)`, int64(6), nil},
 		/*   6 */ {`builtin "math.arith"; include "test-resources/iterator.expr"; it=$(ds,3); mul(it)`, int64(0), nil},
 		/*   7 */ {`builtin "math.arith"; include "test-resources/file-reader.expr"; it=$(ds,"test-resources/int.list"); mul(it)`, int64(12000), nil},
@@ -27,8 +27,13 @@ func TestIteratorParser(t *testing.T) {
 		/*  16 */ {`include "test-resources/filter.expr"; it=$(ds,10); it++`, int64(2), nil},
 		/*  17 */ {`it=$({"next":func(){5}}); it++`, int64(5), nil},
 		/*  18 */ {`it=$({"next":func(){5}}); it.clean`, nil, nil},
+		/*  19 */ {`it=$({1:"one",2:"two",3:"three"}); it++`, int64(1), nil},
+		/*  20 */ {`it=$({1:"one",2:"two",3:"three"}, "default", "value"); it++`, "one", nil},
+		/*  21 */ {`it=$({1:"one",2:"two",3:"three"}, "desc", "key"); it++`, int64(3), nil},
+		/*  22 */ {`it=$({1:"one",2:"two",3:"three"}, "asc", "item"); it++`, NewList([]any{int64(1), "one"}), nil},
+		/*  23 */ {`builtin "os.file"; fileReadIterator("test-file.txt") map ${_index}`, NewList([]any{int64(0), int64(1)}), nil},
 	}
 
-	//runTestSuiteSpec(t, section, inputs, 18)
-	runTestSuite(t, section, inputs)
+	runTestSuiteSpec(t, section, inputs, 23)
+	// runTestSuite(t, section, inputs)
 }

t_list_test.go

@@ -23,8 +23,8 @@ func TestListParser(t *testing.T) {
 		/*   9 */ {`mul([1,4,3.0,2])`, float64(24.0), nil},
 		/*  10 */ {`add([1,"hello"])`, nil, `add(): param nr 2 (2 in 1) has wrong type string, number expected`},
 		/*  11 */ {`[a=1,b=2,c=3] but a+b+c`, int64(6), nil},
-		/*  12 */ {`[1,2,3] << 2+2`, newListA(int64(1), int64(2), int64(3), int64(4)), nil},
-		/*  13 */ {`2-1 >> [2,3]`, newListA(int64(1), int64(2), int64(3)), nil},
+		/*  12 */ {`[1,2,3] <+ 2+2`, newListA(int64(1), int64(2), int64(3), int64(4)), nil},
+		/*  13 */ {`2-1 +> [2,3]`, newListA(int64(1), int64(2), int64(3)), nil},
 		/*  14 */ {`[1,2,3][1]`, int64(2), nil},
 		/*  15 */ {`ls=[1,2,3] but ls[1]`, int64(2), nil},
 		/*  16 */ {`ls=[1,2,3] but ls[-1]`, int64(3), nil},
@@ -33,25 +33,25 @@ func TestListParser(t *testing.T) {
 		/*  19 */ {`["a", "b", "c"]`, newList([]any{"a", "b", "c"}), nil},
 		/*  20 */ {`#["a", "b", "c"]`, int64(3), nil},
 		/*  21 */ {`"b" in ["a", "b", "c"]`, true, nil},
-		/*  22 */ {`a=[1,2]; (a)<<3`, newListA(int64(1), int64(2), int64(3)), nil},
-		/*  23 */ {`a=[1,2]; (a)<<3; a`, newListA(int64(1), int64(2)), nil},
+		/*  22 */ {`a=[1,2]; (a)<+3`, newListA(int64(1), int64(2), int64(3)), nil},
+		/*  23 */ {`a=[1,2]; (a)<+3; a`, newListA(int64(1), int64(2)), nil},
 		/*  24 */ {`["a","b","c","d"][1]`, "b", nil},
 		/*  25 */ {`["a","b","c","d"][1,1]`, nil, `[1:19] one index only is allowed`},
 		/*  26 */ {`[0,1,2,3,4][:]`, newListA(int64(0), int64(1), int64(2), int64(3), int64(4)), nil},
-		/*  27 */ {`["a", "b", "c"] << ;`, nil, `[1:18] infix operator "<<" requires two non-nil operands, got 1`},
+		/*  27 */ {`["a", "b", "c"] <+ ;`, nil, `[1:18] infix operator "<+" requires two non-nil operands, got 1`},
 		/*  28 */ {`2 << 3;`, int64(16), nil},
-		/*  29 */ {`but >> ["a", "b", "c"]`, nil, `[1:6] infix operator ">>" requires two non-nil operands, got 0`},
+		/*  29 */ {`but +> ["a", "b", "c"]`, nil, `[1:6] infix operator "+>" requires two non-nil operands, got 0`},
 		/*  30 */ {`2 >> 3;`, int64(0), nil},
-		/*  31 */ {`a=[1,2]; a<<3`, newListA(int64(1), int64(2), int64(3)), nil},
-		/*  33 */ {`a=[1,2]; 5>>a`, newListA(int64(5), int64(1), int64(2)), nil},
-		/*  34 */ {`L=[1,2]; L[0]=9; L`, newListA(int64(9), int64(2)), nil},
-		/*  35 */ {`L=[1,2]; L[5]=9; L`, nil, `index 5 out of bounds (0, 1)`},
-		/*  36 */ {`L=[1,2]; L[]=9; L`, nil, `[1:12] index/key specification expected, got [] [list]`},
-		/*  37 */ {`L=[1,2]; L[nil]=9;`, nil, `[1:12] index/key is nil`},
-		/*  38 */ {`[0,1,2,3,4][2:3]`, newListA(int64(2)), nil},
-		/*  39 */ {`[0,1,2,3,4][3:-1]`, newListA(int64(3)), nil},
-		/*  40 */ {`[0,1,2,3,4][-3:-1]`, newListA(int64(2), int64(3)), nil},
-		/*  41 */ {`[0,1,2,3,4][0:]`, newListA(int64(0), int64(1), int64(2), int64(3), int64(4)), nil},
+		/*  31 */ {`a=[1,2]; a<+3`, newListA(int64(1), int64(2), int64(3)), nil},
+		/*  32 */ {`a=[1,2]; 5+>a`, newListA(int64(5), int64(1), int64(2)), nil},
+		/*  33 */ {`L=[1,2]; L[0]=9; L`, newListA(int64(9), int64(2)), nil},
+		/*  34 */ {`L=[1,2]; L[5]=9; L`, nil, `index 5 out of bounds (0, 1)`},
+		/*  35 */ {`L=[1,2]; L[]=9; L`, nil, `[1:12] index/key specification expected, got [] [list]`},
+		/*  36 */ {`L=[1,2]; L[nil]=9;`, nil, `[1:12] index/key is nil`},
+		/*  37 */ {`[0,1,2,3,4][2:3]`, newListA(int64(2)), nil},
+		/*  38 */ {`[0,1,2,3,4][3:-1]`, newListA(int64(3)), nil},
+		/*  30 */ {`[0,1,2,3,4][-3:-1]`, newListA(int64(2), int64(3)), nil},
+		/*  40 */ {`[0,1,2,3,4][0:]`, newListA(int64(0), int64(1), int64(2), int64(3), int64(4)), nil},
 	}
 
 	// t.Setenv("EXPR_PATH", ".")

t_operator_test.go

@@ -14,10 +14,31 @@ func TestOperator(t *testing.T) {
 		/*   1 */ {`a=1; unset "a"; a`, nil, `undefined variable or function "a"`},
 		/*   2 */ {`a=1; unset ["a", "b"]`, int64(1), nil},
 		/*   3 */ {`f=func(){3}; unset "f()"`, int64(1), nil},
+		/*   4 */ {`a=1; a<<=1+0`, int64(2), nil},
+		/*   5 */ {`a=2; a>>=1+0`, int64(1), nil},
+		/*   6 */ {`1<<1`, int64(2), nil},
+		/*   7 */ {`1>>1`, int64(0), nil},
+		/*   8 */ {`1|2`, int64(3), nil},
+		/*   9 */ {`a=1; a|=2`, int64(3), nil},
+		/*  10 */ {`3&1`, int64(1), nil},
+		/*  11 */ {`a=3; a&=1`, int64(1), nil},
+		/*  12 */ {`~1`, int64(-2), nil},
+		/*  13 */ {`0x10`, int64(16), nil},
+		/*  14 */ {`0x1X`, nil, `[1:5] two adjacent operators: "1" and "X"`},
+		/*  15 */ {`0o10`, int64(8), nil},
+		/*  16 */ {`0b10`, int64(2), nil},
+		/*  17 */ {`~true`, nil, `[1:2] prefix/postfix operator "~" do not support operand 'true' [bool]`},
+		/*  18 */ {`1^2`, int64(3), nil},
+		/*  19 */ {`3^2`, int64(1), nil},
+		/*  20 */ {`a=1; a^=2`, int64(3), nil},
+		/*  21 */ {`a=1; ++a`, int64(2), nil},
+		/*  22 */ {`a=1; --a`, int64(0), nil},
+		/*  23 */ {`[1,2,3] map var("_")`, []any{1, 2, 3}, nil},
+		/*  24 */ {`[1,2,3] map $_`, newList([]any{1, 2, 3}), nil},
 	}
 
 	// t.Setenv("EXPR_PATH", ".")
 
-	//runTestSuiteSpec(t, section, inputs, 3)
-	runTestSuite(t, section, inputs)
+	runTestSuiteSpec(t, section, inputs, 24)
+	// runTestSuite(t, section, inputs)
 }

t_parser_test.go

@@ -78,8 +78,8 @@ func TestGeneralParser(t *testing.T) {
 		/*  64 */ {`"1.5" != `, nil, `[1:8] infix operator "!=" requires two non-nil operands, got 1`},
 		/*  65 */ {"+1.5", float64(1.5), nil},
 		/*  66 */ {"+", nil, `[1:2] prefix operator "+" requires one non-nil operand`},
-		/*  67 */ {"4 / 0", nil, `division by zero`},
-		/*  68 */ {"4.0 / 0", nil, `division by zero`},
+		/*  67 */ {"4 / 0", nil, `[1:4] division by zero`},
+		/*  68 */ {"4.0 / 0", nil, `[1:6] division by zero`},
 		/*  69 */ {"4.0 / \n2", float64(2.0), nil},
 		/*  70 */ {`123`, int64(123), nil},
 		/*  71 */ {`1.`, float64(1.0), nil},
@@ -142,6 +142,6 @@ func TestGeneralParser(t *testing.T) {
 	}
 
 	// t.Setenv("EXPR_PATH", ".")
-	//runTestSuiteSpec(t, section, inputs, 130)
+	// runTestSuiteSpec(t, section, inputs, 114)
 	runTestSuite(t, section, inputs)
 }

t_plugin_test.go

@@ -30,9 +30,29 @@ func TestPluginExists(t *testing.T) {
 
 func TestMakePluginName(t *testing.T) {
 	name := "json"
-	want := "expr-" + name + "-plugin.so"
+	want := "expr-" + name + "-plugin" + SHAREDLIBRARY_EXTENSION
 
 	if got := makePluginName(name); got != want {
 		t.Errorf("makePluginName(%q) failed: Got: %q, Want: %q", name, got, want)
 	}
 }
+
+// func TestLoadPluginName(t *testing.T) {
+// 	name := "json"
+// 	// want := "expr-" + name + "-plugin
+// 	want := 1
+
+// 	os.Setenv("PLUGINS", "${HOME}/go/src/git.portale-stac.it/go")
+// 	// os.Setenv("EXPR_PLUGIN_PATH", "${PLUGINS}/expr-json-plugin:${PLUGINS}/expr-csv-plugin")
+// 	os.Setenv("EXPR_PLUGIN_PATH", "${PLUGINS}")
+// 	got, err := importPluginFromSearchPath(name)
+
+// 	if err != nil {
+// 		t.Errorf("importPluginFromSearchPath(%q) failed: %v", name, err)
+// 		return
+// 	}
+
+// 	if got != want {
+// 		t.Errorf("importPluginFromSearchPath(%q) failed: Got: %q, Want: %q", name, got, want)
+// 	}
+// }

t_strings_test.go

@@ -9,6 +9,7 @@ import (
 )
 
 func TestStringsParser(t *testing.T) {
+	section := "String"
 	inputs := []inputType{
 		/*  1 */ {`"uno" + "due"`, `unodue`, nil},
 		/*  2 */ {`"uno" + 2`, `uno2`, nil},
@@ -16,6 +17,12 @@ func TestStringsParser(t *testing.T) {
 		/*  4 */ {`"uno" * (2+1)`, `unounouno`, nil},
 		/*  5 */ {`"abc"[1]`, `b`, nil},
 		/*  6 */ {`#"abc"`, int64(3), nil},
+		/*  7 */ {`"192.168.0.240" / "."`, newListA("192", "168", "0", "240"), nil},
+		/*  8 */ {`("192.168.0.240" / ".")[1]`, "168", nil},
+		/*  9 */ {`"AF3B0Dz" / 2`, newListA("AF", "3B", "0D", "z"), nil},
+		/* 10 */ {`"AF3B0Dz" / 0`, nil, "[1:12] division by zero"},
 	}
-	runTestSuite(t, "String", inputs)
+
+	// runTestSuiteSpec(t, section, inputs, 8)
+	runTestSuite(t, section, inputs)
 }

term.go

@@ -13,23 +13,29 @@ type termPriority uint32
 const (
 	priNone termPriority = iota
 	priRange
+	priIterOp // map, filter, digest, etc
 	priBut
 	priAssign
+	priInsert
 	priOr
 	priAnd
 	priNot
 	priRelational
-	priBinary
+	priBitwiseOr
+	priBitwiseAnd
+	priBitwiseNot
 	priSum
 	priProduct
 	priFraction
 	priSelector
+	priBinShift
 	priSign
 	priFact
 	priIterValue
 	priDefault
 	priIncDec
 	priDot
+	priDereference
 	priValue
 )
 
@@ -199,6 +205,10 @@ func (term *term) errIncompatibleType(value any) error {
 		term.source(), value, TypeName(value))
 }
 
+func (term *term) errDivisionByZero() error {
+	return term.tk.Errorf("division by zero")
+}
+
 func (term *term) Errorf(template string, args ...any) (err error) {
 	err = term.tk.Errorf(template, args...)
 	return

token.go

@@ -79,6 +79,10 @@ func (tk *Token) IsSymbol(sym Symbol) bool {
 	return tk.Sym == sym
 }
 
+func (tk *Token) SetSymbol(sym Symbol) {
+	tk.Sym = sym
+}
+
 func (tk *Token) Errorf(template string, args ...any) (err error) {
 	err = fmt.Errorf(fmt.Sprintf("[%d:%d] ", tk.row, tk.col)+template, args...)
 	return

utils.go

@@ -218,6 +218,15 @@ func ToGoInt(value any, description string) (i int, err error) {
 	return
 }
 
+func ToGoString(value any, description string) (s string, err error) {
+	if s, ok := value.(string); ok {
+		return s, nil
+	} else {
+		err = fmt.Errorf("%s expected string, got %s (%v)", description, TypeName(value), value)
+	}
+	return
+}
+
 func ForAll[T, V any](ts []T, fn func(T) V) []V {
 	result := make([]V, len(ts))
 	for i, t := range ts {