From 857cf00caf43d4c4e771ce2b83cc031e77166fb0 Mon Sep 17 00:00:00 2001
From: joe-conigliaro <joe-conigliaro@users.noreply.github.com>
Date: Mon, 26 Aug 2019 21:18:58 +1000
Subject: [PATCH] builtin.string: make trim_left/right() behave correctly

---
 vlib/builtin/string.v      | 16 +++++++++-------
 vlib/builtin/string_test.v |  6 ++++++
 2 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/vlib/builtin/string.v b/vlib/builtin/string.v
index 1b31a822ec..82a37b08c5 100644
--- a/vlib/builtin/string.v
+++ b/vlib/builtin/string.v
@@ -608,22 +608,24 @@ pub fn (s string) trim(c byte) string {
 }
 
 pub fn (s string) trim_left(cutset string) string {
-	mut start := s.index(cutset)
-	if start != 0 {
+	if s.len == 0 || cutset.len == 0 {
 		return s
 	}
-	for start < s.len - 1 && s[start] == cutset[0] {
-		start++
+	mut pos := 0
+	cs_arr := cutset.bytes()
+	for s[pos] in cs_arr {
+		pos++
 	}
-	return s.right(start)
+	return s.right(pos)
 }
 
 pub fn (s string) trim_right(cutset string) string {
-	if s.len == 0 {
+	if s.len == 0 || cutset.len == 0 {
 		return s
 	}
 	mut pos := s.len - 1
-	for s[pos] == cutset[0] {
+	cs_arr := cutset.bytes()
+	for s[pos] in cs_arr {
 		pos--
 	}
 	return s.left(pos+1)
diff --git a/vlib/builtin/string_test.v b/vlib/builtin/string_test.v
index af17648dad..0bbe2c158f 100644
--- a/vlib/builtin/string_test.v
+++ b/vlib/builtin/string_test.v
@@ -307,6 +307,9 @@ fn test_trim_left() {
 	assert s.trim_left(' ') == 'module main'
 	s = ' module main'
 	assert s.trim_left(' ') == 'module main'
+	// test cutset
+	s = 'banana'
+	assert s.trim_left('ba') == 'nana'
 }
 
 fn test_trim_right() {
@@ -314,6 +317,9 @@ fn test_trim_right() {
 	assert s.trim_right(' ') == 'module main'
 	s = 'module main '
 	assert s.trim_right(' ') == 'module main'
+	// test cutset
+	s = 'banana'
+	assert s.trim_right('na') == 'b'
 }
 
 fn test_all_after() {