(defparameter *nodes* '((living-room (you are in a 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.))))

(defun pickup (object)
	(cond ((member object
								 (objects-at *location* *objects* *object-locations*))
				 (push (list object 'body) *object-locations*)
				 `(you are now carring the ,object))
				(t '(you cannot get that.))))

(defun inventory ()
	(cons 'items- (objects-at 'body *objects* *object-locations*)))

(defun game-repl ()
	(let ((cmd (game-read)))
		(unless (eq (car cmd) 'quit)
			(game-print (game-eval cmd))
			(game-repl))))

(defun game-read ()
	(let ((cmd (read-from-string
							 (concatenate 'string "(" (read-line) ")"))))
		(flet ((quote-it (x)
										 (list 'quote x)))
			(cons (car cmd) (mapcar #'quote-it (cdr cmd))))))

(defparameter *allowed-commands* '(look walk pickup inventory))

(defun game-eval (sexp)
	(if (member (car sexp) *allowed-commands*)
		(eval sexp)
		'(i do not know that command.)))

(defun tweak-text (lst caps lit)
	(when lst
		(let ((item (car lst))
					(rest (cdr lst)))
			(cond ((eql item #\space) (cons item (tweak-text rest caps lit)))
						((member item '(#\! #\? #\.)) (cons item (tweak-text rest t lit)))
						((eql item #\") (tweak-text rest caps (not lit)))
						(lit (cons item (tweak-text rest nil lit)))
						(caps (cons (char-upcase item) (tweak-text rest nil lit)))
						(t (cons (char-downcase item) (tweak-text rest nil nil)))))))

(defun game-print (lst)
	(princ (coerce (tweak-text (coerce (string-trim "() "
																									 (prin1-to-string lst))
																		 'list)
														 t
														 nil)
								 'string))
	(fresh-line))