removed all traces of 'extends' -- it's not any shorter or more convenient than just setting the prototype

lib/coffee_script/grammar.y

@@ -10,7 +10,7 @@ token TRY CATCH FINALLY THROW
 token BREAK CONTINUE
 token FOR IN WHILE
 token SWITCH CASE
-token EXTENDS SUPER
+token SUPER
 token DELETE
 token NEWLINE
 token COMMENT
@@ -30,7 +30,7 @@ prechigh
   right    DELETE
   left     "."
   right    THROW FOR IN WHILE NEW
-  left     UNLESS IF ELSE EXTENDS
+  left     UNLESS IF ELSE
   left     ":"
   right    RETURN
 preclow
@@ -69,7 +69,6 @@ rule
   | Call
   | Code
   | Operation
-  | Extend
   ;
 
   # We have to take extra care to convert these statements into expressions.
@@ -255,11 +254,6 @@ rule
     SUPER "(" ArgList ")"             { result = CallNode.new(:super, val[2]) }
   ;
 
-  # Extending a class.
-  Extend:
-    IDENTIFIER EXTENDS Expression     { result = ExtendNode.new(val[0], val[2]) }
-  ;
-
   # The array literal.
   Array:
     "[" ArgList "]"                   { result = ArrayNode.new(val[1]) }