anchor.diff:  						   (error "illegal tag, not in toplevel"))
   		               (not ,x)		nil
   		               ,@(awhen if-atom `((atom ,x)	,!))
  +		               ,@(awhen if-slot-value `((%slot-value? ,x) ,!))
   
   		               ,@(awhen (or if-named-function if-function)
   			               `((%setq-named-function? ,x)
  
positive.code: 
  (defmacro metacode-walker-statements (name args &key (if-atom nil)
  										  			 (if-cons nil)
  										  			 (if-function nil)
  										  			 (if-lambda nil)
  										  			 (if-named-function nil)
  
negative.code: ;;;;; TRE compiler
  ;;;;; Copyright (c) 2010-2011 Sven Klose <pixel@copei.de>
  
  (defun function-copier-0 (x body-statements)
    `(function ,,@(awhen (lambda-name ,x) (list !))
  