From a91bd5a5bb036e1b426e04e5d533c6496254fe49 Mon Sep 17 00:00:00 2001
From: CC <jeff@chipnetics.com>
Date: Thu, 12 May 2022 00:43:01 -0600
Subject: [PATCH] builtin: add a map.clear() method (#14373)

---
 vlib/builtin/map.v      | 8 ++++++++
 vlib/builtin/map_test.v | 8 ++++++++
 2 files changed, 16 insertions(+)

diff --git a/vlib/builtin/map.v b/vlib/builtin/map.v
index faed595665..622ccdffd7 100644
--- a/vlib/builtin/map.v
+++ b/vlib/builtin/map.v
@@ -294,6 +294,14 @@ pub fn (mut m map) move() map {
 	return r
 }
 
+// clear clears the map without deallocating the allocated data.
+// It does it by setting the map length to `0`
+// Example: a.clear() // `a.len` and `a.key_values.len` is now 0
+pub fn (mut m map) clear() {
+	m.len = 0
+	m.key_values.len = 0
+}
+
 [inline]
 fn (m &map) key_to_index(pkey voidptr) (u32, u32) {
 	hash := m.hash_fn(pkey)
diff --git a/vlib/builtin/map_test.v b/vlib/builtin/map_test.v
index 672efc3b09..4ed7a09860 100644
--- a/vlib/builtin/map_test.v
+++ b/vlib/builtin/map_test.v
@@ -245,6 +245,14 @@ fn test_mut_arg() {
 	assert a == 10
 }
 
+fn test_clear() {
+	mut m := map[string]int{}
+	m['one'] = 1
+	m['two'] = 2
+	m.clear()
+	assert m.len == 0
+}
+
 fn test_delete() {
 	mut m := map[string]int{}
 	m['one'] = 1