Generalize path function queries.

Added unit tests for namespace-based path queries.

3 files changed, 36 insertions, 34 deletions

diff --git a/etree.go b/etree.go
index a24d4d4..259d2aa 100644
--- a/etree.go
+++ b/etree.go
@@ -433,16 +433,6 @@ func (e *Element) findDefaultNamespaceURI() string {
 	return e.parent.findDefaultNamespaceURI()
 }
 
-// hasText returns true if the element has character data immediately
-// folllowing the element's opening tag.
-func (e *Element) hasText() bool {
-	if len(e.Child) == 0 {
-		return false
-	}
-	_, ok := e.Child[0].(*CharData)
-	return ok
-}
-
 // namespacePrefix returns the namespace prefix associated with the element.
 func (e *Element) namespacePrefix() string {
 	return e.Space
diff --git a/path.go b/path.go
index 82db0ac..8997cb2 100644
--- a/path.go
+++ b/path.go
@@ -46,7 +46,9 @@ The following function filters are also supported:
     [text()='val']              Keep elements whose text matches val.
     [local-name()='val']        Keep elements whose un-prefixed tag matches val.
     [name()='val']              Keep elements whose full tag exactly matches val.
+    [namespace-prefix()]        Keep elements with non-empty namespace prefixes.
     [namespace-prefix()='val']  Keep elements whose namespace prefix matches val.
+    [namespace-uri()]           Keep elements with non-empty namespace URIs.
     [namespace-uri()='val']     Keep elements whose namespace URI matches val.
 
 Here are some examples of Path strings:
@@ -280,15 +282,12 @@ func (c *compiler) parseSelector(path string) selector {
 	}
 }
 
-var fnTable = map[string]struct {
-	hasFn    func(e *Element) bool
-	getValFn func(e *Element) string
-}{
-	"local-name":       {nil, (*Element).name},
-	"name":             {nil, (*Element).FullTag},
-	"namespace-prefix": {nil, (*Element).namespacePrefix},
-	"namespace-uri":    {nil, (*Element).NamespaceURI},
-	"text":             {(*Element).hasText, (*Element).Text},
+var fnTable = map[string]func(e *Element) string{
+	"local-name":       (*Element).name,
+	"name":             (*Element).FullTag,
+	"namespace-prefix": (*Element).namespacePrefix,
+	"namespace-uri":    (*Element).NamespaceURI,
+	"text":             (*Element).Text,
 }
 
 // parseFilter parses a path filter contained within [brackets].
@@ -314,11 +313,11 @@ func (c *compiler) parseFilter(path string) filter {
 		case key[0] == '@':
 			return newFilterAttrVal(key[1:], value)
 		case strings.HasSuffix(key, "()"):
-			fn := key[:len(key)-2]
-			if t, ok := fnTable[fn]; ok && t.getValFn != nil {
-				return newFilterFuncVal(t.getValFn, value)
+			name := key[:len(key)-2]
+			if fn, ok := fnTable[name]; ok {
+				return newFilterFuncVal(fn, value)
 			}
-			c.err = ErrPath("path has unknown function " + fn)
+			c.err = ErrPath("path has unknown function " + name)
 			return nil
 		default:
 			return newFilterChildText(key, value)
@@ -330,11 +329,11 @@ func (c *compiler) parseFilter(path string) filter {
 	case path[0] == '@':
 		return newFilterAttr(path[1:])
 	case strings.HasSuffix(path, "()"):
-		fn := path[:len(path)-2]
-		if t, ok := fnTable[fn]; ok && t.hasFn != nil {
-			return newFilterFunc(t.hasFn)
+		name := path[:len(path)-2]
+		if fn, ok := fnTable[name]; ok {
+			return newFilterFunc(fn)
 		}
-		c.err = ErrPath("path has unknown function " + fn)
+		c.err = ErrPath("path has unknown function " + name)
 		return nil
 	case isInteger(path):
 		pos, _ := strconv.Atoi(path)
@@ -496,16 +495,16 @@ func (f *filterAttrVal) apply(p *pather) {
 // filterFunc filters the candidate list for elements satisfying a custom
 // boolean function.
 type filterFunc struct {
-	fn func(e *Element) bool
+	fn func(e *Element) string
 }
 
-func newFilterFunc(fn func(e *Element) bool) *filterFunc {
+func newFilterFunc(fn func(e *Element) string) *filterFunc {
 	return &filterFunc{fn}
 }
 
 func (f *filterFunc) apply(p *pather) {
 	for _, c := range p.candidates {
-		if f.fn(c) {
+		if f.fn(c) != "" {
 			p.scratch = append(p.scratch, c)
 		}
 	}
diff --git a/path_test.go b/path_test.go
index d94968a..0e02227 100644
--- a/path_test.go
+++ b/path_test.go
@@ -37,7 +37,7 @@ var testXML = `
 		<author>James Linn</author>
 		<author>Vaidyanathan Nagarajan</author>
 		<year>2003</year>
-		<p:price>49.99</p:price>
+		<price>49.99</p:price>
 		<editor>
 		</editor>
 	</book>
@@ -66,7 +66,7 @@ var tests = []test{
 	{"./bookstore/book/title", []string{"Everyday Italian", "Harry Potter", "XQuery Kick Start", "Learning XML"}},
 	{"./bookstore/book/author", []string{"Giada De Laurentiis", "J K. Rowling", "James McGovern", "Per Bothner", "Kurt Cagle", "James Linn", "Vaidyanathan Nagarajan", "Erik T. Ray"}},
 	{"./bookstore/book/year", []string{"2005", "2005", "2003", "2003"}},
-	{"./bookstore/book/p:price", []string{"30.00", "29.99", "49.99", "39.95"}},
+	{"./bookstore/book/p:price", []string{"30.00", "29.99", "39.95"}},
 	{"./bookstore/book/isbn", nil},
 
 	// descendant queries
@@ -75,7 +75,7 @@ var tests = []test{
 	{".//title", []string{"Everyday Italian", "Harry Potter", "XQuery Kick Start", "Learning XML"}},
 	{".//bookstore//title", []string{"Everyday Italian", "Harry Potter", "XQuery Kick Start", "Learning XML"}},
 	{".//book/title", []string{"Everyday Italian", "Harry Potter", "XQuery Kick Start", "Learning XML"}},
-	{".//p:price/.", []string{"30.00", "29.99", "49.99", "39.95"}},
+	{".//p:price/.", []string{"30.00", "29.99", "39.95"}},
 	{".//price", []string{"30.00", "29.99", "49.99", "39.95"}},
 
 	// positional queries
@@ -90,7 +90,7 @@ var tests = []test{
 	{"./bookstore/book[-4]/title", "Everyday Italian"},
 	{"./bookstore/book[-5]/title", nil},
 
-	// text queries
+	// text function queries
 	{"./bookstore/book[author='James McGovern']/title", "XQuery Kick Start"},
 	{"./bookstore/book[author='Per Bothner']/title", "XQuery Kick Start"},
 	{"./bookstore/book[author='Kurt Cagle']/title", "XQuery Kick Start"},
@@ -102,6 +102,19 @@ var tests = []test{
 	{"//book/author[text()='Kurt Cagle']", "Kurt Cagle"},
 	{"//book/editor[text()]", []string{"Clarkson Potter", "\n\t\t"}},
 
+	// namespace function queries
+	{"//*[namespace-uri()]", []string{"30.00", "29.99", "39.95"}},
+	{"//*[namespace-uri()='urn:books-com:prices']", []string{"30.00", "29.99", "39.95"}},
+	{"//*[namespace-uri()='foo']", nil},
+	{"//*[namespace-prefix()]", []string{"30.00", "29.99", "39.95"}},
+	{"//*[namespace-prefix()='p']", []string{"30.00", "29.99", "39.95"}},
+	{"//*[name()='p:price']", []string{"30.00", "29.99", "39.95"}},
+	{"//*[local-name()='price']", []string{"30.00", "29.99", "49.99", "39.95"}},
+	{"//price[namespace-uri()='']", []string{"49.99"}},
+	{"//price[namespace-prefix()='']", []string{"49.99"}},
+	{"//price[name()='price']", []string{"49.99"}},
+	{"//price[local-name()='price']", []string{"30.00", "29.99", "49.99", "39.95"}},
+
 	// attribute queries
 	{"./bookstore/book[@category='WEB']/title", []string{"XQuery Kick Start", "Learning XML"}},
 	{"./bookstore/book[@path='/books/xml']/title", []string{"Learning XML"}},