automatic conversion of arguments into arrays

lib/coffee_script/grammar.y

@@ -12,6 +12,7 @@ token FOR IN BY WHEN WHILE
 token SWITCH LEADING_WHEN
 token DELETE INSTANCEOF TYPEOF
 token SUPER EXTENDS
+token ARGUMENTS
 token NEWLINE
 token COMMENT
 token JS
@@ -97,6 +98,7 @@ rule
   | REGEX                             { result = LiteralNode.new(val[0]) }
   | BREAK                             { result = LiteralNode.new(val[0]) }
   | CONTINUE                          { result = LiteralNode.new(val[0]) }
+  | ARGUMENTS                         { result = LiteralNode.new(val[0]) }
   | TRUE                              { result = LiteralNode.new(true) }
   | FALSE                             { result = LiteralNode.new(false) }
   | YES                               { result = LiteralNode.new(true) }

lib/coffee_script/lexer.rb

@@ -15,6 +15,7 @@ module CoffeeScript
                   "for", "in", "by", "where", "while",
                   "switch", "when",
                   "super", "extends",
+                  "arguments",
                   "delete", "instanceof", "typeof"]
 
     # Token matching regexes.

lib/coffee_script/nodes.rb

@@ -134,6 +134,10 @@ module CoffeeScript
   class LiteralNode < Node
     STATEMENTS = ['break', 'continue']
 
+    CONVERSIONS = {
+      'arguments' => 'Array.prototype.slice.call(arguments, 0)'
+    }
+
     attr_reader :value
 
     def initialize(value)
@@ -146,9 +150,10 @@ module CoffeeScript
     alias_method :statement_only?, :statement?
 
     def compile_node(o)
+      val    = CONVERSIONS[@value.to_s] || @value.to_s
       indent = statement? ? o[:indent] : ''
       ending = statement? ? ';' : ''
-      write(indent + @value.to_s + ending)
+      write("#{indent}#{val}#{ending}")
     end
   end
 

test/fixtures/execution/test_arguments.coffee

@@ -15,3 +15,10 @@ print(area(
   x1
   y1
 ) is 100)
+
+
+# Arguments are turned into arrays.
+curried: =>
+  print(area.apply(this, arguments.concat(20, 20)) is 100)
+
+curried(10, 10)