anchor.diff:              :funcs `((,start-var () ,start-var)
                        (,advance-step
                         ()
  -                      (tagbody
  -                         ,top
  -			 (labels ((local-reset
  -				      (&optional finished-at)
  -				    (let ((finished-at (or finished-at ,*time-var*)))
  -				      (setf ,step-var 0)
  -				      (,init-name finished-at)
  -				      (go ,top))))
  -			   (case= ,step-var
  -			     ,@(loop :for i :from 0 :by 3
  -				  :for s :in (cons start-var
  -						   (mapcar (lambda (_) (caar (expire-test _)))
  -							   compiled-forms))
  -				  :for c :in compiled-forms :append
  -				  (gen-t-r-step c i s top step-var)))))))
  +		      (block nil
  +			(tagbody
  +			   ,top
  +			   (return
  +			     (labels ((local-reset
  +					  (&optional finished-at)
  +					(let ((finished-at (or finished-at ,*time-var*)))
  +					  (setf ,step-var 0)
  +					  (,init-name finished-at)
  +					  (go ,top))))
  +			       (case= ,step-var
  +				 ,@(loop :for i :from 0 :by 3
  +				      :for s :in (cons start-var
  +						       (mapcar (lambda (_) (caar (expire-test _)))
  +							       compiled-forms))
  +				      :for c :in compiled-forms :append
  +				      (gen-t-r-step c i s top step-var)))))))))
               :body `(,advance-step))
              compiled-forms)
        t)))
  
positive.code:             :funcs `((,start-var () ,start-var)
                       (,advance-step
                        ()
                        (tagbody
                           ,top
  			 (labels ((local-reset
  				      (&optional finished-at)
  				    (let ((finished-at (or finished-at ,*time-var*)))
  				      (setf ,step-var 0)
  				      (,init-name finished-at)
  				      (go ,top))))
  			   (case= ,step-var
  			     ,@(loop :for i :from 0 :by 3
  				  :for s :in (cons start-var
  						   (mapcar (lambda (_) (caar (expire-test _)))
  							   compiled-forms))
  				  :for c :in compiled-forms :append
  				  (gen-t-r-step c i s top step-var))
  			     (,(* 3 (length compiled-forms))
  			       (local-reset (,(caar (expire-test (car (last compiled-forms))))))))))))
              :body `(,advance-step))
             compiled-forms)
       t)))
  
negative.code:          (incf ,step-var 2)
           (go ,top))
  	(,(+ 1 step-num)
  	  (,init-name ,*time-var*)
  	  (incf ,step-var)
  	  (return))
          (,(+ 2 step-num)
            (if (,expired-name)
                (progn (incf ,step-var) (go ,top))
  