attempt at getting variables to work.

__for.cpp

@@ -5,9 +5,9 @@
 namespace jet {
 
    __for::__for(coreutils::ZString &in, coreutils::MString &out, Global &global) : Tag(in, out, global) {
-   	if(!keywordExists(coreutils::ZString("begin")))
+   	if(!variableDefined(coreutils::ZString("begin")))
 	     throw coreutils::Exception("begin keyword must be specified.");
-	   if(!keywordExists(coreutils::ZString("end")))
+	   if(!variableDefined(coreutils::ZString("end")))
 	     throw coreutils::Exception("end keyword must be specified.");
 
       for(;;) {