fix name() function

Update name() function to accept a node set as an argument. Also, the name() function returns a namespace+local-name according to the spec. The change fixes function behavior as well.

Author: Denys Smirnov

build.go

@@ -234,7 +234,18 @@ func (b *builder) processFunctionNode(root *functionNode) (query, error) {
 		}
 		qyOutput = &functionQuery{Input: argQuery, Func: notFunc}
 	case "name":
-		qyOutput = &functionQuery{Input: b.firstInput, Func: nameFunc}
+		inp := b.firstInput
+		if len(root.Args) > 1 {
+			return nil, errors.New("xpath: name function must have at most one parameter")
+		}
+		if len(root.Args) == 1 {
+			argQuery, err := b.processNode(root.Args[0])
+			if err != nil {
+				return nil, err
+			}
+			inp = argQuery
+		}
+		qyOutput = &functionQuery{Input: inp, Func: nameFunc}
 	case "last":
 		qyOutput = &functionQuery{Input: b.firstInput, Func: lastFunc}
 	case "position":

func.go

@@ -92,7 +92,15 @@ func sumFunc(q query, t iterator) interface{} {
 
 // nameFunc is a XPath functions name([node-set]).
 func nameFunc(q query, t iterator) interface{} {
-	return t.Current().LocalName()
+	v := q.Select(t)
+	if v == nil {
+		return ""
+	}
+	ns := v.Prefix()
+	if ns == "" {
+		return v.LocalName()
+	}
+	return ns + ":" + v.LocalName()
 }
 
 func asBool(t iterator, v interface{}) bool {

xpath_test.go

@@ -192,6 +192,7 @@ func TestOr_And(t *testing.T) {
 func TestFunction(t *testing.T) {
 	testEval(t, html, "boolean(//*[@id])", true)
 	testEval(t, html, "boolean(//*[@x])", false)
+	testEval(t, html, "name(//title)", "title")
 	testXPath2(t, html, "//*[name()='a']", 3)
 	testXPath(t, html, "//*[starts-with(name(),'h1')]", "h1")
 	testXPath(t, html, "//*[ends-with(name(),'itle')]", "title") // Head title