Allow paren queries

gjson.go

@@ -737,7 +737,13 @@ func parseArrayPath(path string) (r arrayPathResult) {
 					r.alogok = true
 					r.alogkey = path[2:]
 					r.path = path[:1]
-				} else if path[1] == '[' {
+				} else if path[1] == '[' || path[1] == '(' {
+					var end byte
+					if path[1] == '[' {
+						end = ']'
+					} else {
+						end = ')'
+					}
 					r.query.on = true
 					// query
 					i += 2
@@ -755,7 +761,7 @@ func parseArrayPath(path string) (r arrayPathResult) {
 							path[i] == '<' ||
 							path[i] == '>' ||
 							path[i] == '%' ||
-							path[i] == ']' {
+							path[i] == end {
 							break
 						}
 					}
@@ -817,7 +823,7 @@ func parseArrayPath(path string) (r arrayPathResult) {
 										break
 									}
 								}
-							} else if path[i] == ']' {
+							} else if path[i] == end {
 								if i+1 < len(path) && path[i+1] == '#' {
 									r.query.all = true
 								}
@@ -1495,16 +1501,22 @@ func splitPossiblePipe(path string) (left, right string, ok bool) {
 				if i == len(path) {
 					return
 				}
-				if path[i] == '[' {
+				if path[i] == '[' || path[i] == '(' {
+					var start, end byte
+					if path[i] == '[' {
+						start, end = '[', ']'
+					} else {
+						start, end = '(', ')'
+					}
 					// inside selector, balance brackets
 					i++
 					depth := 1
 					for ; i < len(path); i++ {
 						if path[i] == '\\' {
 							i++
-						} else if path[i] == '[' {
+						} else if path[i] == start {
 							depth++
-						} else if path[i] == ']' {
+						} else if path[i] == end {
 							depth--
 							if depth == 0 {
 								break

gjson_test.go

@@ -1853,3 +1853,12 @@ func TestQueryArrayValues(t *testing.T) {
 	assert(t, Get(json, `a*.#[_%"John*"]#|#`).String() == "0")
 	assert(t, Get(json, `a*.#[="123"]#|#`).String() == "1")
 }
+
+func TestParenQueries(t *testing.T) {
+	json := `{
+		"friends": [{"a":10},{"a":20},{"a":30},{"a":40}]
+	}`
+	assert(t, Get(json, "friends.#(a>9)#|#").Int() == 4)
+	assert(t, Get(json, "friends.#(a>10)#|#").Int() == 3)
+	assert(t, Get(json, "friends.#(a>40)#|#").Int() == 0)
+}