From 527b9e13faafeefdaaeda0dec3cd723619a3990c Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@medvednikov.com>
Date: Tue, 23 Jul 2019 22:57:06 +0200
Subject: [PATCH] `key in map` syntax

---
 compiler/main.v         |  1 +
 compiler/parser.v       | 19 +++++++++++++------
 compiler/table.v        | 11 ++++-------
 vlib/builtin/map.v      |  5 +++++
 vlib/builtin/map_test.v |  1 +
 5 files changed, 24 insertions(+), 13 deletions(-)

diff --git a/compiler/main.v b/compiler/main.v
index 8abc2a129d..ba3a11735c 100644
--- a/compiler/main.v
+++ b/compiler/main.v
@@ -244,6 +244,7 @@ typedef map map_string;
 #define _PUSH(arr, val, tmp, tmp_typ) {tmp_typ tmp = (val); array__push(arr, &tmp);}
 #define _PUSH_MANY(arr, val, tmp, tmp_typ) {tmp_typ tmp = (val); array__push_many(arr, tmp.data, tmp.len);}
 #define _IN(typ, val, arr) array_##typ##_contains(arr, val) 
+#define _IN_MAP(val, m) map__exists(m, val) 
 #define ALLOC_INIT(type, ...) (type *)memdup((type[]){ __VA_ARGS__ }, sizeof(type)) 
 
 //================================== GLOBALS =================================*/   
diff --git a/compiler/parser.v b/compiler/parser.v
index 4b472cad5f..60bf4f5bf0 100644
--- a/compiler/parser.v
+++ b/compiler/parser.v
@@ -1970,22 +1970,29 @@ fn (p mut Parser) expression() string {
 			return 'int'
 		}
 	}
-	// a in [1,2,3]
+	// `a in [1, 2, 3]` 
+	// `key in map` 
 	if p.tok == .key_in {
 		p.fgen(' ')
 		p.check(.key_in)
 		p.fgen(' ')
 		p.gen(', ')
 		arr_typ := p.expression()
-		if !arr_typ.starts_with('array_') {
-			p.error('`in` requires an array')
+		is_map := arr_typ.starts_with('map_') 
+		if !arr_typ.starts_with('array_') && !is_map { 
+			p.error('`in` requires an array/map')
 		}
 		T := p.table.find_type(arr_typ)
-		if !T.has_method('contains') {
+		if !is_map && !T.has_method('contains') {
 			p.error('$arr_typ has no method `contains`')
 		}
-		// `typ` is element type
-		p.cgen.set_placeholder(ph, '_IN($typ, ')
+		// `typ` is element's type
+		if is_map {
+			p.cgen.set_placeholder(ph, '_IN_MAP( ')
+		} 
+		else { 
+			p.cgen.set_placeholder(ph, '_IN($typ, ')
+		} 
 		p.gen(')')
 		return 'bool'
 	}
diff --git a/compiler/table.v b/compiler/table.v
index 6256d1d05d..37f7095024 100644
--- a/compiler/table.v
+++ b/compiler/table.v
@@ -699,7 +699,7 @@ fn new_file_import_table(file_path string) *FileImportTable {
 }
 
 fn (fit &FileImportTable) known_import(mod string) bool {
-	return fit.imports.exists(mod) || fit.is_aliased(mod)
+	return mod in fit.imports || fit.is_aliased(mod)
 }
 
 fn (fit mut FileImportTable) register_import(mod string) {
@@ -707,7 +707,7 @@ fn (fit mut FileImportTable) register_import(mod string) {
 }
 
 fn (fit mut FileImportTable) register_alias(alias string, mod string) {
-	if fit.imports.exists(alias) {
+	if alias in fit.imports { 
 		panic('cannot import $mod as $alias: import name $alias already in use in "${fit.file_path}".')
 		return 
 	} 
@@ -715,7 +715,7 @@ fn (fit mut FileImportTable) register_alias(alias string, mod string) {
 }
 
 fn (fit &FileImportTable) known_alias(alias string) bool {
-	return fit.imports.exists(alias)
+	return alias in fit.imports 
 }
 
 fn (fit &FileImportTable) is_aliased(mod string) bool {
@@ -728,8 +728,5 @@ fn (fit &FileImportTable) is_aliased(mod string) bool {
 }
 
 fn (fit &FileImportTable) resolve_alias(alias string) string {
-	if fit.imports.exists(alias) {
-		return fit.imports[alias]
-	}
-	return ''
+	return fit.imports[alias]
 }
diff --git a/vlib/builtin/map.v b/vlib/builtin/map.v
index 5eafc1c13b..1ed9f89c98 100644
--- a/vlib/builtin/map.v
+++ b/vlib/builtin/map.v
@@ -170,6 +170,11 @@ fn (m map) get(key string, out voidptr) bool {
 }
 
 pub fn (m map) exists(key string) bool {
+	panic('map.exists(key) was removed from the language. Use `key in map` instead.') 
+	return false 
+}
+
+fn (m map) _exists(key string) bool {
 	return !isnil(m.root) && m.root.find2(key, m.element_size) 
 }
 
diff --git a/vlib/builtin/map_test.v b/vlib/builtin/map_test.v
index 3a21e4d930..b4c5edac7d 100644
--- a/vlib/builtin/map_test.v
+++ b/vlib/builtin/map_test.v
@@ -21,6 +21,7 @@ fn test_map() {
 	assert m['hi'] == 80
 	assert m['hello'] == 101 
 	assert m.size == 2 
+	assert 'hi' in m 
 	mut sum := 0
 	mut key_sum := '' 
 	// Test `for in`