Fix closures not being able to use by reference

Author: thekid

ChangeLog.md

@@ -3,6 +3,7 @@ XP Compiler ChangeLog
 
 ## ?.?.? / ????-??-??
 
+* Fixed closures not being able to use by reference - @thekid
 * Implemented parameter annotations via `$param: inject` - @thekid
 
 ## 0.6.0 / 2017-10-15

src/main/php/lang/ast/Parse.class.php

@@ -731,7 +731,12 @@ private function func($name, $modifiers) {
         $this->token= $this->advance();
         $use= [];
         while (')' !== $this->token->symbol->id) {
-          $use[]= '$'.$this->token->value;
+          if ('&' === $this->token->value) {
+            $this->token= $this->advance();
+            $use[]= '&$'.$this->token->value;
+          } else {
+            $use[]= '$'.$this->token->value;
+          }
           $this->token= $this->advance();
           if (')' === $this->token->symbol->id) break;
           $this->token= $this->expect(',');

src/test/php/lang/ast/unittest/parse/FunctionsTest.class.php

@@ -92,14 +92,23 @@ public function default_closure() {
   }
 
   #[@test]
-  public function default_closure_with_use() {
+  public function default_closure_with_use_by_vaue() {
     $block= ['+' => [['(variable)' => 'a'], ['(literal)' => '1']]];
     $this->assertNodes(
       [['(' => [null, [], [], [['return' => $block]], null, ['$a', '$b']]]],
       $this->parse('function() use($a, $b) { return $a + 1; };')
     );
   }
 
+  #[@test]
+  public function default_closure_with_use_by_reference() {
+    $block= ['+' => [['(variable)' => 'a'], ['(literal)' => '1']]];
+    $this->assertNodes(
+      [['(' => [null, [], [], [['return' => $block]], null, ['$a', '&$b']]]],
+      $this->parse('function() use($a, &$b) { return $a + 1; };')
+    );
+  }
+
   #[@test]
   public function short_closure() {
     $block= ['+' => [['(variable)' => 'a'], ['(literal)' => '1']]];