changed the structer of the selector components: now all case are a list value assigned as right operand of the selector operator

operand-list.go

@@ -5,11 +5,15 @@
 package expr
 
 // -------- list term
+func newListTermA(args ...*term) *term {
+	return newListTerm(args)
+}
+
 func newListTerm(args []*term) *term {
 	return &term{
-		tk:       *NewToken(0, 0, SymList, "[]"),
+		tk:       *NewValueToken(0, 0, SymList, "[]", args),
 		parent:   nil,
-		children: args,
+		children: nil,
 		position: posLeaf,
 		priority: priValue,
 		evalFunc: evalList,
@@ -18,8 +22,9 @@ func newListTerm(args []*term) *term {
 
 // -------- list func
 func evalList(ctx ExprContext, self *term) (v any, err error) {
-	items := make([]any, len(self.children))
+	list, _ := self.value().([]*term)
-	for i, tree := range self.children {
+	items := make([]any, len(list))
+	for i, tree := range list {
 		var param any
 		if param, err = tree.compute(ctx); err != nil {
 			break
@@ -31,3 +36,31 @@ func evalList(ctx ExprContext, self *term) (v any, err error) {
 	}
 	return
 }
+
+// // -------- list term
+// func newListTerm(args []*term) *term {
+// 	return &term{
+// 		tk:       *NewToken(0, 0, SymList, "[]"),
+// 		parent:   nil,
+// 		children: args,
+// 		position: posLeaf,
+// 		priority: priValue,
+// 		evalFunc: evalList,
+// 	}
+// }
+
+// // -------- list func
+// func evalList(ctx ExprContext, self *term) (v any, err error) {
+// 	items := make([]any, len(self.children))
+// 	for i, tree := range self.children {
+// 		var param any
+// 		if param, err = tree.compute(ctx); err != nil {
+// 			break
+// 		}
+// 		items[i] = param
+// 	}
+// 	if err == nil {
+// 		v = items
+// 	}
+// 	return
+// }

operator-selector.go

@@ -4,13 +4,71 @@
 // 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
 
 func newSelectorTerm(tk *Token) (inst *term) {
 	return &term{
 		tk:       *tk,
 		children: make([]*term, 0, 3),
-		position: posMultifix,
+		position: posInfix,
 		priority: priSelector,
 		evalFunc: evalSelector,
 	}
@@ -49,7 +107,8 @@ func evalSelector(ctx ExprContext, self *term) (v any, err error) {
 		return
 	}
 
-	caseList := self.children[1:]
+	caseListTerm := self.children[1]
+	caseList, _ := caseListTerm.value().([]*term)
 	for i, caseTerm := range caseList {
 		caseSel := caseTerm.value()
 		if v, err = isSelectorCase(ctx, exprValue, caseSel, i); err != nil || v != nil {

parser.go

@@ -154,6 +154,19 @@ func (self *parser) parseSelectorCase(scanner *scanner, allowVarRef bool, defaul
 	return
 }
 
+func addSelectorCase(selectorTerm, caseTerm *term) {
+	if len(selectorTerm.children) < 2 {
+		caseListTerm := newListTermA(caseTerm)
+		selectorTerm.children = append(selectorTerm.children, caseListTerm)
+	} else {
+		caseListTerm := selectorTerm.children[1]
+		caseList, _ := caseListTerm.value().([]*term)
+		caseList = append(caseList, caseTerm)
+		caseListTerm.tk.Value = caseList
+	}
+	caseTerm.parent = selectorTerm
+}
+
 func (self *parser) parseSelector(scanner *scanner, tree *ast, allowVarRef bool) (selectorTerm *term, err error) {
 	var caseTerm *term
 	tk := scanner.makeToken(SymSelector, '?')
@@ -162,8 +175,9 @@ func (self *parser) parseSelector(scanner *scanner, tree *ast, allowVarRef bool)
 	}
 
 	if caseTerm, err = self.parseSelectorCase(scanner, allowVarRef, false); err == nil {
-		selectorTerm.children = append(selectorTerm.children, caseTerm)
+		addSelectorCase(selectorTerm, caseTerm)
-		caseTerm.parent = selectorTerm
+		// selectorTerm.children = append(selectorTerm.children, caseTerm)
+		// caseTerm.parent = selectorTerm
 	}
 	return
 }
@@ -246,9 +260,7 @@ func (self *parser) parseGeneral(scanner *scanner, allowForest bool, allowVarRef
 				currentTerm, err = tree.addToken2(tk)
 			}
 		case SymQuestion:
-			/*if selectorTerm != nil {
+			if selectorTerm, err = self.parseSelector(scanner, tree, allowVarRef); err == nil {
-				err = tk.Errorf("nested selectors must be enclosed in parentheses")
-			} else*/if selectorTerm, err = self.parseSelector(scanner, tree, allowVarRef); err == nil {
 				currentTerm = selectorTerm
 			}
 		case SymColon, SymDoubleColon:
@@ -256,8 +268,9 @@ func (self *parser) parseGeneral(scanner *scanner, allowForest bool, allowVarRef
 			if selectorTerm == nil {
 				err = tk.Errorf("selector-case outside of a selector context")
 			} else if caseTerm, err = self.parseSelectorCase(scanner, allowVarRef, tk.Sym == SymDoubleColon); err == nil {
-				selectorTerm.children = append(selectorTerm.children, caseTerm)
+				// selectorTerm.children = append(selectorTerm.children, caseTerm)
-				caseTerm.parent = selectorTerm
+				// caseTerm.parent = selectorTerm
+				addSelectorCase(selectorTerm, caseTerm)
 				currentTerm = caseTerm
 				if tk.Sym == SymDoubleColon {
 					selectorTerm = nil

parser_test.go

@@ -155,6 +155,7 @@ func TestParser(t *testing.T) {
 		/* 134 */ {`10 ? {"a"} : {"b"}`, nil, errors.New(`[1:3] no case catches the value (10) of the selection expression`)},
 		/* 135 */ {`10 ? {"a"} :: {"b"} : {"c"}`, nil, errors.New(`[1:22] selector-case outside of a selector context`)},
 		/* 136 */ {`1 ? {"a"} : {"b"} ? ["a"] {"A"} :["b"] {"B"}`, "B", nil},
+		/* 137 */ {`2 + 1 ? {"a"} : {"b"} * 3`, "2bbb", nil},
 	}
 	check_env_expr_path := 113