Updated

Author: AspieSoft

regex.go

@@ -187,6 +187,69 @@ func RepFunc(str []byte, re string, rep func(func(int) []byte) []byte, blank ...
 	return res
 }
 
+func RepFuncFirst(str []byte, re string, rep func(func(int) []byte) []byte, blank ...bool) []byte {
+	reg := Compile(re)
+
+	// ind := reg.FindAllIndex(str, pcre.UTF8)
+	// ind := reg.FindAllIndex(str, 0)
+	pos := reg.FindIndex(str, 0)
+
+	res := []byte{}
+	trim := 0
+	// for _, pos := range ind {
+		v := str[pos[0]:pos[1]]
+		m := reg.Matcher(v, 0)
+
+		if len(blank) != 0 {
+			gCache := map[int][]byte{}
+			r := rep(func(g int) []byte {
+				if v, ok := gCache[g]; ok {
+					return v
+				}
+				v := m.Group(g)
+				gCache[g] = v
+				return v
+			})
+
+			if r == nil {
+				return nil
+			}
+		} else {
+			if trim == 0 {
+				res = append(res, str[:pos[0]]...)
+			} else {
+				res = append(res, str[trim:pos[0]]...)
+			}
+			trim = pos[1]
+
+			gCache := map[int][]byte{}
+			r := rep(func(g int) []byte {
+				if v, ok := gCache[g]; ok {
+					return v
+				}
+				v := m.Group(g)
+				gCache[g] = v
+				return v
+			})
+
+			if r == nil {
+				res = append(res, str[trim:]...)
+				return res
+			}
+
+			res = append(res, r...)
+		}
+	// }
+
+	if len(blank) != 0 {
+		return nil
+	}
+
+	res = append(res, str[trim:]...)
+
+	return res
+}
+
 func RepStr(str []byte, re string, rep []byte) []byte {
 	reg := Compile(re)
 

regex_test.go

@@ -9,32 +9,47 @@ import (
 )
 
 func TestCompile(t *testing.T) {
-	var check = func(s string){
+	var check = func(s string) {
 		re1 := Compile(s)
 		re2 := Compile(s)
 		if re1.Groups() != re2.Groups() {
 			t.Error(s, errors.New("first result does not match cache result"))
 		}
 	}
+
 	check("")
 	check("a(b)")
 }
 
 func TestReplace(t *testing.T) {
-	var check = func(s string, re, r string, e string){
+	var check = func(s string, re, r string, e string) {
 		res := RepStr([]byte(s), re, []byte(r))
 		if !bytes.Equal(res, []byte(e)) {
 			t.Error(res, errors.New("result does not match expected result"))
 		}
 	}
+
 	check("this is a test", `(?#a\s+)test`, "", "this is a ")
 	check("string with `block` quotes", `\'.*?\'`, "'single'", "string with 'single' quotes")
 }
 
+func TestReplaceFirst(t *testing.T) {
+	var check = func(s string, re string, r func(func(int) []byte) []byte, e string) {
+		res := RepFuncFirst([]byte(s), re, r)
+		if !bytes.Equal(res, []byte(e)) {
+			t.Error(res, errors.New("result does not match expected result"))
+		}
+	}
+
+	check("test 1 and test 2", `test`, func(data func(int) []byte) []byte {
+		return []byte{}
+	}, " 1 and test 2")
+}
+
 func TestConcurent(t *testing.T) {
 	for i := 0; i < 10; i++ {
 		for i := 0; i < 10; i++ {
-			go (func(){
+			go (func() {
 				res := RepFunc([]byte("test"), `(t)`, func(data func(int) []byte) []byte {
 					return data(1)
 				})