anchor.diff:         else collect next into args
          finally (return (values params args)))))
   
  -(defun get-param (names params) 
  -  (loop for (a . b) in params 
  +(defun get-param (names params)
  +  (loop for (a . b) in params
        if (member a names) do (return b)))
   
   (defun sys-dir (path)
  
positive.code: 		   res (if (eq eof exp)
  			   :eof
  			   (mapcar
  			    (lambda (v) (alist :type (type-tag v) :value (write-to-string v))) 
  			    (multiple-value-list (eval exp))))))
  	      (error (e) 
  		(setf res (list
  			   (alist 
  			    :type 'error 
  			    :value (front-end-error (format nil "~s" exp) e)))))))))
      (if (eq :eof res)
  	nil
  
negative.code:   (loop for s in (closer-mop:class-slots (class-of instance))
       for slot-name = (slot-definition-name s)
       when (slot-boundp instance slot-name)
       collect (cons (intern (symbol-name slot-name) :keyword)
  		   (slot-value instance slot-name))))
  
  (defun alist (&rest k/v-pairs)
  