merged with datasource-context

context-helpers.go

@@ -0,0 +1,41 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
+// context-helpers.go
+package expr
+
+func cloneContext(sourceCtx ExprContext) (clonedCtx ExprContext) {
+	if sourceCtx != nil {
+		clonedCtx = sourceCtx.Clone()
+	}
+	return
+}
+
+func exportVar(ctx ExprContext, name string, value any) {
+	if name[0] == '@' {
+		name = name[1:]
+	}
+	ctx.setVar(name, value)
+}
+
+func exportFunc(ctx ExprContext, name string, info ExprFunc) {
+	if name[0] == '@' {
+		name = name[1:]
+	}
+	ctx.RegisterFunc(name, info.Functor(), info.MinArgs(), info.MaxArgs())
+}
+
+func exportObjects(destCtx, sourceCtx ExprContext) {
+	exportAll := isEnabled(sourceCtx, control_export_all)
+	// Export variables
+	for _, refName := range sourceCtx.EnumVars(func(name string) bool { return exportAll || name[0] == '@' }) {
+		refValue, _ := sourceCtx.GetVar(refName)
+		exportVar(destCtx, refName, refValue)
+	}
+	// Export functions
+	for _, refName := range sourceCtx.EnumFuncs(func(name string) bool { return exportAll || name[0] == '@' }) {
+		if info, _ := sourceCtx.GetFuncInfo(refName); info != nil {
+			exportFunc(destCtx, refName, info)
+		}
+	}
+}

data-cursor.go

@@ -0,0 +1,62 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
+// data-cursors.go
+package expr
+
+import (
+	"io"
+)
+
+const (
+	initName    = "init"
+	nextName    = "next"
+	currentName = "current"
+)
+
+type dataCursor struct {
+	ds          map[any]*term
+	ctx         ExprContext
+	index       int
+	resource    any
+	nextFunc    Functor
+	currentFunc Functor
+}
+
+func newDataCursor(ctx ExprContext) (dc *dataCursor) {
+	dc = &dataCursor{
+		index: -1,
+		ctx:   ctx.Clone(),
+	}
+	return
+}
+
+func (dc *dataCursor) String() string {
+	return "$(...)"
+}
+
+func (dc *dataCursor) Current() (item any, err error) { // must return io.EOF at the last item
+	ctx := cloneContext(dc.ctx)
+	if item, err = dc.currentFunc.Invoke(ctx, currentName, []any{}); err == nil && item == nil {
+		err = io.EOF
+	}
+	exportObjects(dc.ctx, ctx)
+	return
+}
+
+func (dc *dataCursor) Next() (item any, err error) { // must return io.EOF after the last item
+	ctx := cloneContext(dc.ctx)
+	if item, err = dc.nextFunc.Invoke(ctx, nextName, []any{}); err == nil {
+		if item == nil {
+			err = io.EOF
+		} else {
+			dc.index++
+		}
+	}
+	exportObjects(dc.ctx, ctx)
+	return
+}
+
+func (dc *dataCursor) Index() int {
+	return dc.index
+}

expr_test.go

@@ -27,11 +27,22 @@ func TestExpr(t *testing.T) {
 	succeeded := 0
 	failed := 0
 
-	// inputs1 := []inputType{
-	// 	/*   1 */ {`0?{}`, nil, nil},
-	// }
+	inputs1 := []inputType{
+		/*   1 */ {`
+		ds={
+			"init":func(end){@end=end; @current=0 but true},
+			"current":func(){current},
+			"next":func(){
+				((next=current+1) <= end) ? [true] {@current=next but current} :: {nil}
+			}
+		};
+		it=$(ds,3);
+		it++;
+		it++
+`, int64(1), nil},
+	}
 
-	for i, input := range inputs {
+	for i, input := range inputs1 {
 		var expr Expr
 		var gotResult any
 		var gotErr error

operand-dict.go

@@ -5,10 +5,6 @@
 package expr
 
 // -------- dict term
-// func newDictTermA(args ...*term) *term {
-// 	return newDictTerm(args)
-// }
-
 func newDictTerm(args map[any]*term) *term {
 	return &term{
 		tk:       *NewValueToken(0, 0, SymDict, "{}", args),

operand-expr.go

@@ -27,8 +27,3 @@ func evalExpr(ctx ExprContext, self *term) (v any, err error) {
 	}
 	return
 }
-
-// init
-// func init() {
-// 	registerTermConstructor(SymExpression, newExprTerm)
-// }

operand-func.go

@@ -22,7 +22,7 @@ func newFuncCallTerm(tk *Token, args []*term) *term {
 
 // -------- eval func call
 func evalFuncCall(parentCtx ExprContext, self *term) (v any, err error) {
-	ctx := parentCtx.Clone()
+	ctx := cloneContext(parentCtx)
 	name, _ := self.tk.Value.(string)
 	params := make([]any, len(self.children))
 	for i, tree := range self.children {
@@ -34,37 +34,12 @@ func evalFuncCall(parentCtx ExprContext, self *term) (v any, err error) {
 	}
 	if err == nil {
 		if v, err = ctx.Call(name, params); err == nil {
-			exportAll := isEnabled(ctx, control_export_all)
-			// Export variables
-			for _, refName := range ctx.EnumVars(func(name string) bool { return exportAll || name[0] == '@' }) {
-				refValue, _ := ctx.GetVar(refName)
-				exportVar(parentCtx, refName, refValue)
-			}
-			// Export functions
-			for _, refName := range ctx.EnumFuncs(func(name string) bool { return exportAll || name[0] == '@' }) {
-				if info, _ := ctx.GetFuncInfo(refName); info != nil {
-					exportFunc(parentCtx, refName, info)
-				}
-			}
+			exportObjects(parentCtx, ctx)
 		}
 	}
 	return
 }
 
-func exportVar(ctx ExprContext, name string, value any) {
-	if name[0] == '@' {
-		name = name[1:]
-	}
-	ctx.setVar(name, value)
-}
-
-func exportFunc(ctx ExprContext, name string, info ExprFunc) {
-	if name[0] == '@' {
-		name = name[1:]
-	}
-	ctx.RegisterFunc(name, info.Functor(), info.MinArgs(), info.MaxArgs())
-}
-
 // -------- function definition term
 func newFuncDefTerm(tk *Token, args []*term) *term {
 	return &term{
@@ -107,12 +82,6 @@ func evalFuncDef(ctx ExprContext, self *term) (v any, err error) {
 		paramList := make([]string, 0, len(self.children))
 		for _, param := range self.children {
 			paramList = append(paramList, param.source())
-			// if paramName, ok := param.value().(string); ok {
-			// 	paramList = append(paramList, paramName)
-			// } else {
-			// 	err = fmt.Errorf("invalid function definition: formal param nr %d must be an identifier", i+1)
-			// 	break
-			// }
 		}
 		v = &funcDefFunctor{
 			params: paramList,

operand-iterator.go

@@ -6,58 +6,10 @@ package expr
 
 import (
 	"fmt"
-	"io"
 )
 
 // -------- iterator term
 
-const (
-	initName    = "init"
-	nextName    = "next"
-	currentName = "current"
-)
-
-type dataCursor struct {
-	ds          map[any]*term
-	ctx         ExprContext
-	index       int
-	resource    any
-	nextFunc    Functor
-	currentFunc Functor
-}
-
-func (dc *dataCursor) String() string {
-	var s string
-	if item, err := dc.Current(); err == nil {
-		s = fmt.Sprintf("%v", item)
-	} else {
-		s = "(nil)"
-	}
-	return s
-}
-
-func (dc *dataCursor) Current() (item any, err error) { // must return io.EOF at the last item
-	if item, err = dc.currentFunc.Invoke(dc.ctx, currentName, []any{}); err == nil && item == nil {
-		err = io.EOF
-	}
-	return
-}
-
-func (dc *dataCursor) Next() (item any, err error) { // must return io.EOF after the last item
-	if item, err = dc.nextFunc.Invoke(dc.ctx, nextName, []any{}); err == nil {
-		if item == nil {
-			err = io.EOF
-		} else {
-			dc.index++
-		}
-	}
-	return
-}
-
-func (dc *dataCursor) Index() int {
-	return dc.index
-}
-
 func newIteratorTerm(tk *Token, dsTerm *term, args []*term) *term {
 	tk.Sym = SymIterator
 
@@ -125,10 +77,7 @@ func evalIterator(ctx ExprContext, self *term) (v any, err error) {
 		return
 	}
 
-	dc := &dataCursor{
-		index: -1,
-		ctx:   ctx.Clone(),
-	}
+	dc := newDataCursor(ctx)
 
 	if initFunc, exists := ds[initName]; exists && initFunc != nil {
 		var args []any
@@ -139,9 +88,12 @@ func evalIterator(ctx ExprContext, self *term) (v any, err error) {
 		} else {
 			args = []any{}
 		}
-		if dc.resource, err = initFunc.Invoke(dc.ctx, initName, args); err != nil {
+
+		initCtx := dc.ctx.Clone()
+		if dc.resource, err = initFunc.Invoke(initCtx, initName, args); err != nil {
 			return
 		}
+		exportObjects(dc.ctx, initCtx)
 	}
 
 	dc.nextFunc, _ = ds[nextName]

operator-context.go

@@ -0,0 +1,49 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
+// operator-context-value.go
+package expr
+
+//-------- context term
+
+func newContextTerm(tk *Token) (inst *term) {
+	return &term{
+		tk:       *tk,
+		children: make([]*term, 0, 1),
+		position: posPrefix,
+		priority: priPrePost,
+		evalFunc: evalContextValue,
+	}
+}
+
+func evalContextValue(ctx ExprContext, self *term) (v any, err error) {
+	var childValue any
+
+	var sourceCtx ExprContext
+	if len(self.children) == 0 {
+		sourceCtx = ctx
+	} else if childValue, err = self.evalPrefix(ctx); err == nil {
+		if dc, ok := childValue.(*dataCursor); ok {
+			sourceCtx = dc.ctx
+		}
+	} else {
+		return
+	}
+
+	if sourceCtx != nil {
+		keys := sourceCtx.EnumVars(func(name string) bool { return name[0] != '_' })
+		d := make(map[string]any)
+		for _, key := range keys {
+			d[key], _ = sourceCtx.GetVar(key)
+		}
+		v = d
+	} else {
+		err = self.errIncompatibleType(childValue)
+	}
+	return
+}
+
+// init
+func init() {
+	registerTermConstructor(SymDoubleDollar, newContextTerm)
+}

operator-length.go

@@ -29,9 +29,8 @@ func evalLength(ctx ExprContext, self *term) (v any, err error) {
 	} else if isString(rightValue) {
 		s, _ := rightValue.(string)
 		v = len(s)
-		// } else {
-		// 	v = 1
-		// }
+	} else if it, ok := rightValue.(Iterator); ok {
+		v = it.Index()
 	} else {
 		err = self.errIncompatibleType(rightValue)
 	}

operator-selector.go

@@ -4,65 +4,7 @@
 // operator-selector.go
 package expr
 
-// //-------- export all term
-
-// func newSelectorTerm(tk *Token) (inst *term) {
-// 	return &term{
-// 		tk:       *tk,
-// 		children: make([]*term, 0, 3),
-// 		position: posMultifix,
-// 		priority: priSelector,
-// 		evalFunc: evalSelector,
-// 	}
-// }
-
-// func isSelectorCase(ctx ExprContext, exprValue, caseSel any, caseIndex int) (selectedValue any, err error) {
-// 	caseData, _ := caseSel.(*selectorCase)
-// 	if caseData.filterList == nil {
-// 		selectedValue, err = caseData.caseExpr.eval(ctx, false)
-// 	} else {
-// 		filterList := caseData.filterList.children
-// 		if len(filterList) == 0 && exprValue == int64(caseIndex) {
-// 			selectedValue, err = caseData.caseExpr.eval(ctx, false)
-// 		} else {
-// 			var caseValue any
-// 			for _, caseTerm := range filterList {
-// 				if caseValue, err = caseTerm.compute(ctx); err != nil || caseValue == exprValue {
-// 					selectedValue, err = caseData.caseExpr.eval(ctx, false)
-// 					break
-// 				}
-// 			}
-// 		}
-// 	}
-// 	return
-// }
-
-// func evalSelector(ctx ExprContext, self *term) (v any, err error) {
-// 	var exprValue any
-// 	// var caseList []*term
-
-// 	if err = self.checkOperands(); err != nil {
-// 		return
-// 	}
-// 	exprTerm := self.children[0]
-// 	if exprValue, err = exprTerm.compute(ctx); err != nil {
-// 		return
-// 	}
-
-// 	caseList := self.children[1:]
-// 	for i, caseTerm := range caseList {
-// 		caseSel := caseTerm.value()
-// 		if v, err = isSelectorCase(ctx, exprValue, caseSel, i); err != nil || v != nil {
-// 			break
-// 		}
-// 	}
-// 	if err == nil && v == nil {
-// 		err = exprTerm.tk.Errorf("no case catches the value (%v) of the selection expression", exprValue)
-// 	}
-// 	return
-// }
-
-//-------- export all term
+//-------- selector term
 
 func newSelectorTerm(tk *Token) (inst *term) {
 	return &term{
@@ -74,7 +16,7 @@ func newSelectorTerm(tk *Token) (inst *term) {
 	}
 }
 
-func isSelectorCase(ctx ExprContext, exprValue, caseSel any, caseIndex int) (match bool, selectedValue any, err error) {
+func trySelectorCase(ctx ExprContext, exprValue, caseSel any, caseIndex int) (match bool, selectedValue any, err error) {
 	caseData, _ := caseSel.(*selectorCase)
 	if caseData.filterList == nil {
 		selectedValue, err = caseData.caseExpr.eval(ctx, false)
@@ -113,7 +55,7 @@ func evalSelector(ctx ExprContext, self *term) (v any, err error) {
 	caseList, _ := caseListTerm.value().([]*term)
 	for i, caseTerm := range caseList {
 		caseSel := caseTerm.value()
-		if match, v, err = isSelectorCase(ctx, exprValue, caseSel, i); err != nil || match {
+		if match, v, err = trySelectorCase(ctx, exprValue, caseSel, i); err != nil || match {
 			break
 		}
 	}

scanner.go

@@ -242,6 +242,8 @@ func (self *scanner) fetchNextToken() (tk *Token) {
 			if next, _ := self.peek(); next == '(' {
 				tk = self.moveOn(SymDollarRound, ch, next)
 				tk.source += ")"
+			} else if next == '$' {
+				tk = self.moveOn(SymDoubleDollar, ch, next)
 			} else {
 				tk = self.makeToken(SymDollar, ch)
 			}
@@ -249,8 +251,8 @@ func (self *scanner) fetchNextToken() (tk *Token) {
 			if next, _ := self.peek(); next == ')' {
 				tk = self.moveOn(SymOpenClosedRound, ch, next)
 			} else {
-			tk = self.makeToken(SymOpenRound, ch)
-		}
+				tk = self.makeToken(SymOpenRound, ch)
+			}
 		case ')':
 			tk = self.makeToken(SymClosedRound, ch)
 		case '[':

symbol.go

@@ -63,7 +63,8 @@ const (
 	SymAppend                            //  52: '<<'
 	SymCaret                             //  53: '^'
 	SymDollarRound                       //  54: '$('
-	SymOpenClosedRound //  55: '()'
+	SymOpenClosedRound                   //  55: '()'
+	SymDoubleDollar                      //  56: '$$
 	SymChangeSign
 	SymUnchangeSign
 	SymIdentifier