+;
+; Towers of Hanoi
+;
+; Copyright © 2016 Keith Packard <keithp@keithp.com>
+;
+; This program is free software; you can redistribute it and/or modify
+; it under the terms of the GNU General Public License as published by
+; the Free Software Foundation, either version 2 of the License, or
+; (at your option) any later version.
+;
+; This program is distributed in the hope that it will be useful, but
+; WITHOUT ANY WARRANTY; without even the implied warranty of
+; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+; General Public License for more details.
+;
+
+
+; ANSI control sequences
+
(defun move-to (col row)
(patom "\033[" row ";" col "H" nil)
)
(patom "\033[2J" nil)
)
+(defun display-string (x y str)
+ (move-to x y)
+ (patom str)
+ )
+
+; Here's the pieces to display
+
(setq stack '("*" "**" "***" "****" "*****" "******" "*******"))
(setq top (+ (length stack) 3))
+;
+; Here's all of the stacks of pieces
+; This is generated when the program is run
+;
(setq stacks nil)
-(defun display-string (x y str)
- (move-to x y)
- (patom str)
- )
+; Display one stack, clearing any
+; space above it
(defun display-stack (x y clear stack)
(cond ((= 0 clear)
)
)
+; This should probably be included in the rom image...
+
(defun length (list)
(cond (list (1+ (length (cdr list))))
(0)
)
)
+; Position of the top of the stack on the screen
+; Shorter stacks start further down the screen
+
(defun stack-pos (y stack)
(- y (length stack))
)
+; Display all of the stacks, spaced 20 columns apart
+
(defun display-stacks (x y stacks)
(cond (stacks (progn
(display-stack x 0 (stack-pos y (car stacks)) (car stacks))
)
)
+; Display all of the stacks, then move the cursor
+; out of the way and flush the output
+
(defun display ()
(display-stacks 0 top stacks)
(move-to 1 21)
(flush)
)
-(defun length (l)
- (cond (l (1+ (length (cdr l)))) (0))
- )
+; Reset stacks to the starting state, with
+; all of the pieces in the first stack and the
+; other two empty
(defun reset-stacks ()
(setq stacks (list stack nil nil))
(length stack)
)
+; more functions which could usefully
+; be in the rom image
+
(defun min (a b)
(cond ((< a b) a)
(b)
)
)
+; Replace a stack in the list of stacks
+; with a new value
+
(defun replace (list pos member)
(cond ((= pos 0) (cons member (cdr list)))
((cons (car list) (replace (cdr list) (1- pos) member)))
)
)
+; Move a piece from the top of one stack
+; to the top of another
+
(defun move-piece (from to)
(let ((from-stack (nth stacks from))
(to-stack (nth stacks to))
)
)
+; The implementation of the game
+
(defun _hanoi (n from to use)
(cond ((= 1 n)
(progn
)
)
+; A pretty interface which
+; resets the state of the game,
+; clears the screen and runs
+; the program
+
(defun hanoi ()
(setq len (reset-stacks))
(clear)