Add support for double-quotes in filter path queries

helpers.go

@@ -299,10 +299,10 @@ func indentLF(n int, source string) string {
 	}
 }
 
-// nextIndex returns the index of the next occurrence of sep in s,
-// starting from offset.  It returns -1 if the sep string is not found.
-func nextIndex(s, sep string, offset int) int {
-	switch i := strings.Index(s[offset:], sep); i {
+// nextIndex returns the index of the next occurrence of byte ch in s,
+// starting from offset.  It returns -1 if the byte is not found.
+func nextIndex(s string, ch byte, offset int) int {
+	switch i := strings.IndexByte(s[offset:], ch); i {
 	case -1:
 		return -1
 	default:

path.go

@@ -242,12 +242,17 @@ func splitPath(path string) []string {
 	var pieces []string
 	start := 0
 	inquote := false
+	var quote byte
 	for i := 0; i+1 <= len(path); i++ {
-		if path[i] == '\'' {
-			inquote = !inquote
-		} else if path[i] == '/' && !inquote {
-			pieces = append(pieces, path[start:i])
-			start = i + 1
+		if !inquote {
+			if path[i] == '\'' || path[i] == '"' {
+				inquote, quote = true, path[i]
+			} else if path[i] == '/' {
+				pieces = append(pieces, path[start:i])
+				start = i + 1
+			}
+		} else if path[i] == quote {
+			inquote = false
 		}
 	}
 	return append(pieces, path[start:])
@@ -302,30 +307,34 @@ func (c *compiler) parseFilter(path string) filter {
 		return nil
 	}
 
-	// Filter contains [@attr='val'], [fn()='val'], or [tag='val']?
-	eqindex := strings.Index(path, "='")
-	if eqindex >= 0 {
-		rindex := nextIndex(path, "'", eqindex+2)
-		if rindex != len(path)-1 {
-			c.err = ErrPath("path has mismatched filter quotes.")
-			return nil
-		}
-
-		key := path[:eqindex]
-		value := path[eqindex+2 : rindex]
+	// Filter contains [@attr='val'], [@attr="val"], [fn()='val'],
+	// [fn()="val"], [tag='val'] or [tag="val"]?
+	eqindex := strings.IndexByte(path, '=')
+	if eqindex >= 0 && eqindex+1 < len(path) {
+		quote := path[eqindex+1]
+		if quote == '\'' || quote == '"' {
+			rindex := nextIndex(path, quote, eqindex+2)
+			if rindex != len(path)-1 {
+				c.err = ErrPath("path has mismatched filter quotes.")
+				return nil
+			}
 
-		switch {
-		case key[0] == '@':
-			return newFilterAttrVal(key[1:], value)
-		case strings.HasSuffix(key, "()"):
-			name := key[:len(key)-2]
-			if fn, ok := fnTable[name]; ok {
-				return newFilterFuncVal(fn, value)
+			key := path[:eqindex]
+			value := path[eqindex+2 : rindex]
+
+			switch {
+			case key[0] == '@':
+				return newFilterAttrVal(key[1:], value)
+			case strings.HasSuffix(key, "()"):
+				name := key[:len(key)-2]
+				if fn, ok := fnTable[name]; ok {
+					return newFilterFuncVal(fn, value)
+				}
+				c.err = ErrPath("path has unknown function " + name)
+				return nil
+			default:
+				return newFilterChildText(key, value)
 			}
-			c.err = ErrPath("path has unknown function " + name)
-			return nil
-		default:
-			return newFilterChildText(key, value)
 		}
 	}
 

path_test.go

@@ -118,6 +118,7 @@ var tests = []test{
 	{"./bookstore/book[@category='WEB']/title", []string{"XQuery Kick Start", "Learning XML"}},
 	{"./bookstore/book[@path='/books/xml']/title", []string{"Learning XML"}},
 	{"./bookstore/book[@category='COOKING']/title[@lang='en']", "Everyday Italian"},
+	{`./bookstore/book[@category="COOKING"]/title[@lang="en"]`, "Everyday Italian"},
 	{"./bookstore/book/title[@lang='en'][@sku='150']", "Harry Potter"},
 	{"./bookstore/book/title[@lang='fr']", nil},
 	{"//p:price[@p:tax='1.99']", []string{"29.99"}},
@@ -144,6 +145,8 @@ var tests = []test{
 	{"./bookstore/book[]", errorResult("etree: path contains an empty filter expression.")},
 	{"./bookstore/book[@category='WEB'", errorResult("etree: path has invalid filter [brackets].")},
 	{"./bookstore/book[@category='WEB]", errorResult("etree: path has mismatched filter quotes.")},
+	{`./bookstore/book[@category='WEB"]`, errorResult("etree: path has mismatched filter quotes.")},
+	{`./bookstore/book[@category="WEB']`, errorResult("etree: path has mismatched filter quotes.")},
 	{"./bookstore/book[author]a", errorResult("etree: path has invalid filter [brackets].")},
 	{"/][", errorResult("etree: path has invalid filter [brackets].")},
 }