Re: 'Money wanted' algorithm (Lisp version)

[Ken Tilton <tilt@bway.net>]

>>Program Make_Money;
>
>>Uses
>>  Nothing;
>
>>begin
>>  Repeat
>>    Find(EmptyCoffeeCup);
>>    Find(BusyStreet);
>>    Repeat
>>      Sit(MiddleOfStreet)
>>    Until Sun(Down)
>>  Until Hell(FrozenOver)
>>end.

Hmmm.

(defparameter *self* (make-instance 'person)))
(defparameter *sun* 'up)
(defparameter *hell* 'hotter-n-blazes)
(defparameter *cups* (list (make-instance 'cup :contents 'java) ...)
(defparameter *corners* (make-instance 'corner :traffic 'light)...)

(defun main ()
  (do ()
      ((eql *hell* 'frozen-over))
    (let ((cup (find-if 'empty *cups* :key #'contents))
          (corner (find-if 'heavyy *corners* :key #'traffic)))
      (sit *self* :where corner :with cup)
      (do ()
          ((eql *sun* 'down))
        (beg *self* "~&Buddy, can you spare a dime?"))))

(defmethod sit ((who person) &key where with)
  (assert (and where with) "There's a hole in the spec!")
  (setf (butt person) where)
  (setf (hand person) with))

(defmethod beg ((who person) rap)
  (declare (ignore person))
  (format t rap))



Yes, I have deviated from the spec. :) I'm a cowboy. And without a Lisp
editor, I cannot guarantee the parens. <G>