anchor.diff:  		     `(when (,(if (eq to 'below) '>= '>) ,var ,to-var)
   			(go end))
   		     :step `(incf ,var))))
  -	       (singleton #'identity
  -			  (lambda (x) (and (symbolp x) (not (constantp x)))))
  +	       'simple-var-parser
   	       'type-spec-parser
   	       (alternative (keyword-parser 'from)
   			    (keyword-parser 'upfrom))
  
positive.code: 				 (,by-var,form1))
  		     :termination nil
  		     :step `(incf ,var ,by-var))))
  	       (singleton #'identity
  			  (lambda (x) (and (symbolp x) (not (constantp x)))))
  	       'type-spec-parser
  	       (keyword-parser 'by)
  	       (singleton #'identity (constantly t))))
  
  
negative.code: 		     `(when (,(if (eq to 'below) '>= '>) ,var ,to-var)
  			(go end))
  		     :step `(incf ,var))))
  	       'simple-var-parser
  	       'type-spec-parser
  	       (alternative (keyword-parser 'to)
  			    (keyword-parser 'upto)
  