gistfile1.lisp

(defparameter *nodes* '((living-room (you are in the living-room. a wizard is snoring loudly on the couch.))
    (garden (you are in a beautiful garden. there is a well in front of you.))
    (attic (you are in the attic. there is a giant welding torch in the corner.))))

(defun describe-location (location nodes)
    (cadr (assoc location nodes)))

(defparameter *edges* '((living-room (garden west door) (attic upstairs ladder))
    (garden (living-room east door))
    (attic (living-room downstairs ladder))))

(defun describe-path (edge)
    `(there is a ,(caddr edge) going ,(cadr edge) from here.))

(defun describe-paths (location edges)
    (apply #'append (mapcar #'describe-path (cdr (assoc location edges)))))

(defparameter *objects* '(whiskey bucket frog chain))

(defparameter *object-locations* '((whiskey living-room)
    (bucket living-room)
    (chain garden)
    (frog garden)))

(defun objects-at (loc objs obj-locs)
    (labels ((at-loc-p (obj)
        (eq (cadr (assoc obj obj-locs)) loc)))
    (remove-if-not #'at-loc-p objs)))

(defun describe-objects (loc objs obj-loc)
    (labels ((describe-obj (obj)
        `(you see a ,obj on the floor.)))
    (apply #'append (mapcar #'describe-obj (objects-at loc objs obj-loc)))))

(defparameter *location* 'living-room)

(defun look ()
    (append
        (describe-location *location* *nodes*)
        (describe-paths *location* *edges*)
        (describe-objects *location* *objects* *object-locations*)))

(defun walk (direction)
     (let ((next (find direction
        (cdr (assoc *location* *edges*))
        :key #'cadr)))
     (if next
        (progn (setf *location* (car next))
            (look))
        '(you cannot go that way.))))