anchor.diff:  (defmacro pf (&body body)
     "Convenience macro for `pfunc' that automatically wraps BODY in a lambda."
     `(pfunc (lambda () ,@body)))
  +
  +(pushnew 'pf *patterns*)
   
   ;;; pr
   
  
positive.code:       (pdef pdef-name pattern))
      pattern))
  
  (setf (documentation 'pbind 'type) (documentation 'pbind 'function))
  
  (defmethod print-object ((pbind pbind) stream)
  
negative.code:   (if (length= 1 pairs)
        `(pdef ,key ,@pairs)
        `(pbind :pdef ,key ,@pairs)))
  
  (pushnew 'pb *patterns*)
  
  (defclass pbind-pstream (pbind pstream)
    ()
  