3.4.3 Text Game Engine

Code Chapter 5 of LandOfLisp, with the modifications discussed below.

What to hand in

Report the REPL log (described below) from running rwalk!-worker (see below) and all the lisp files you created or modified.

Hints

You may need to know about the following LISP commands (see Graham): dolist, dotimes, list, append, let, let*, if, when, unless, setf, mapcar, lambda.

Random Landscapes

Create random landscapes using (landscape n f1 f2) where n is the number of nodes and f1,f2 are the min to max fanout from a room (number of rooms connecting to this one). Internally, landscape will rewrite the *edges* and *nodes* and *objects* and *objects-location* variables.

To do this, create the random *nodes* first then, create random edges by selecting f1 to f1 nodes, at random. To select the right number of nodes from the fanout, use

(defun within (x y) (+ x (* (- y x) (randf 1.0))))

(round (within f1 f2))

To create random node names, e.g. use (gensym "garden"). To create random descriptions, just use (format nil "You are in ~a.~%" nodeName). To add the new node to *objects* using (push newnode *nodes*).

To pull a random node, use

(defun any (alist)
  (nth (randi (length alist)) alist))

(any *nodes*)

To create random objects, use e.g. (gensym "sword") then put them into randomly selected rooms.

Random Walk

Write a random walk routine that walks around the random landscape, picking up everything it encounters, everywhere:

(defun !rwalk-worker (&optional (rooms 20) (f1 1) (f2 5) (steps 100))
    (reset-seed)           
    (landscape 20 1 5)      
    (format t "nodes: ~a~%~%edges: ~a~%~%objects: ~a~%~%at: ~a~%~%"
            *nodes* *edges* *objects* *object-locations*)
    (dotimes (i steps) 
           (rwalk))
    (inventory))

Write a deftest that uses !rwalk-worker that checks for the right inventory output.

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