Add for-in statement

grammar.coffee

@@ -20,6 +20,7 @@ module.exports = compiler.grammar
       @if_statement,
       @switch_statement,
       @for_statement,
+      @for_in_statement,
       @break_statement,
       @statement_block,
       @return_statement,
@@ -66,6 +67,16 @@ module.exports = compiler.grammar
       ")",
       @statement)
 
+    for_in_statement: -> seq(
+      keyword("for"),
+      "(",
+      optional(keyword("var")),
+      @identifier,
+      keyword("in"),
+      @expression,
+      ")",
+      @statement)
+
     return_statement: -> seq(
       keyword("return"),
       optional(@expression),

grammar_test/statements.txt

@@ -48,7 +48,25 @@ for (;;) {
     (expression_statement)
     (statement_block
       (expression_statement (function_call (identifier) (identifier))))))
-    
+
+============================================
+For-in statements
+============================================
+
+for (var item in items)
+  log(item);
+
+for (item in items)
+  log(item);
+
+---
+
+(program
+  (for_in_statement (identifier) (identifier)
+    (expression_statement (function_call (identifier) (identifier))))
+  (for_in_statement (identifier) (identifier)
+    (expression_statement (function_call (identifier) (identifier)))))
+
 ============================================
 Return statements
 ============================================