From 7ea688aa43612614b00ddab4ec463cbed4a2ad70 Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@medvednikov.com>
Date: Wed, 24 Jul 2019 13:04:57 +0200
Subject: [PATCH] fix mutable array args

---
 compiler/fn.v            |  3 +--
 compiler/parser.v        | 32 +++++++++++++++-----------------
 compiler/tests/fn_test.v | 18 ++++++++++++++++++
 3 files changed, 34 insertions(+), 19 deletions(-)

diff --git a/compiler/fn.v b/compiler/fn.v
index 66441e8b6c..a5005859a8 100644
--- a/compiler/fn.v
+++ b/compiler/fn.v
@@ -631,8 +631,7 @@ fn (p mut Parser) fn_args(f mut Fn) {
 			if !p.first_run() && !p.table.known_type(typ2) {
 				p.error('fn_args: unknown type $typ2')
 			}
-			if is_mut {
-				// && !typ2.starts_with('array_') {
+			if is_mut { 
 				typ2 += '*'
 			}
 			v := Var {
diff --git a/compiler/parser.v b/compiler/parser.v
index 3364a380f5..e23a507acb 100644
--- a/compiler/parser.v
+++ b/compiler/parser.v
@@ -1736,11 +1736,12 @@ fn (p mut Parser) dot(str_typ string, method_ph int) string {
 }
 
 fn (p mut Parser) index_expr(typ string, fn_ph int) string {
-	//if p.fileis('main.v') {
-		//println('index expr typ=$typ')
-	//}
 	// a[0]
 	v := p.expr_var
+	//if p.fileis('fn_test.v') {
+		//println('index expr typ=$typ')
+		//println(v.name) 
+	//}
 	is_map := typ.starts_with('map_')
 	is_str := typ == 'string'
 	is_arr0 := typ.starts_with('array_')
@@ -1912,7 +1913,11 @@ fn (p mut Parser) index_expr(typ string, fn_ph int) string {
 				p.gen('$index_expr ]')
 			}
 			else {
-				p.gen('( *($typ*) array__get($index_expr) )')
+				if is_ptr { 
+					p.gen('( *($typ*) array__get(* $index_expr) )')
+				}  else { 
+					p.gen('( *($typ*) array__get($index_expr) )')
+				} 
 			}
 		}
 		else if is_str && !p.builtin_pkg {
@@ -2076,13 +2081,13 @@ fn (p mut Parser) expression() string {
 
 fn (p mut Parser) term() string {
 	line_nr := p.scanner.line_nr
-	if p.fileis('fn_test') {
-		println('\nterm() $line_nr')
-	}
+	//if p.fileis('fn_test') {
+		//println('\nterm() $line_nr')
+	//}
 	typ := p.unary()
-	if p.fileis('fn_test') {
-		println('2: $line_nr')
-	}
+	//if p.fileis('fn_test') {
+		//println('2: $line_nr')
+	//}
 	// `*` on a newline? Can't be multiplication, only dereference
 	if p.tok == .mul && line_nr != p.scanner.line_nr {
 		return typ
@@ -3117,13 +3122,6 @@ fn (p mut Parser) for_st() {
 			// TODO don't call map_get() for each key, fetch values while traversing
 			// the tree (replace `map_keys()` above with `map_key_vals()`) 
 			p.genln('$var_typ $val = $def; map_get($tmp, $i, & $val);') 
-			
-			/* 
-			p.genln('for (int l = 0; l < $tmp . entries.len; l++) {') 
-			p.genln('Entry entry = *((Entry*) (array__get($tmp .entries, l)));') 
-			p.genln('string $i = entry.key;') 
-			p.genln('$var_typ $val; map_get($tmp, $i, & $val);') 
-			*/ 
 		} 
 	}
 	// `for val in vals`
diff --git a/compiler/tests/fn_test.v b/compiler/tests/fn_test.v
index 6279b62088..bf9cd2f33b 100644
--- a/compiler/tests/fn_test.v
+++ b/compiler/tests/fn_test.v
@@ -63,6 +63,24 @@ fn myprint(s string, ..) {
 	println('/* /* comment */ */')
 }
 
+fn modify_array(a mut []int) {
+	a[0] = 10 
+	for i in 0..a.len {
+		a[i] = a[i] * 2
+	}
+	a << 888 
+} 
+
+fn test_mut() {
+	mut nums := [1, 2, 3] 
+	modify_array(mut nums) 
+	assert nums.len == 4 
+	assert nums[0] == 20 
+	assert nums[1] == 4
+	assert nums[2] == 6 
+	assert nums[3] == 888 
+} 
+
 fn test_fns() {
 	// no asserts for now, just test function declarations above 
 }