From 17e8c1d6283518bcae25ca656f148e26ee7d6461 Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@medvednikov.com>
Date: Tue, 30 Jul 2019 21:27:31 +0200
Subject: [PATCH] map.delete(key)

---
 vlib/builtin/map.v      | 26 ++++++++++++++++++++++++++
 vlib/builtin/map_test.v |  6 ++++--
 2 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/vlib/builtin/map.v b/vlib/builtin/map.v
index 1ed9f89c98..ea6ab03db4 100644
--- a/vlib/builtin/map.v
+++ b/vlib/builtin/map.v
@@ -169,6 +169,32 @@ fn (m map) get(key string, out voidptr) bool {
 	return m.root.find(key, out, m.element_size) 
 }
 
+pub fn (n mut Node) delete(key string, element_size int) { 
+	if n.key == key {
+		C.memset(n.val, 0, element_size)
+		return 
+	} 
+	else if n.key > key {
+		if isnil(n.left) {
+			return 
+		}  else { 
+			n.left.delete(key, element_size) 
+		} 
+	} 
+	else {
+		if isnil(n.right) {
+			return 
+		}  else { 
+			n.right.delete(key, element_size) 
+		} 
+	} 
+} 
+
+pub fn (m mut map) delete(key string) { 
+	m.root.delete(key, m.element_size) 
+	m.size-- 
+} 
+
 pub fn (m map) exists(key string) bool {
 	panic('map.exists(key) was removed from the language. Use `key in map` instead.') 
 	return false 
diff --git a/vlib/builtin/map_test.v b/vlib/builtin/map_test.v
index b4c5edac7d..e493e6d5a2 100644
--- a/vlib/builtin/map_test.v
+++ b/vlib/builtin/map_test.v
@@ -36,13 +36,15 @@ fn test_map() {
 	assert keys.len == 2 
 	assert keys[0] == 'hi'
 	assert keys[1] == 'hello' 
+	m.delete('hi') 
+	assert m.size == 1 
+	assert m['hi'] == 0
+	//assert m.keys().len == 1 
 	//// 
 	mut users := map[string]User{} 
 	users['1'] = User{'Peter'} 
 	peter := users['1']
 	assert  peter.name == 'Peter' 
-	println(peter.name) 
-
 	mut a := A{
 		m: map[string]int{} 
 		users: map[string]User{}