4 ; Copyright © 2016 Keith Packard <keithp@keithp.com>
6 ; This program is free software; you can redistribute it and/or modify
7 ; it under the terms of the GNU General Public License as published by
8 ; the Free Software Foundation, either version 2 of the License, or
9 ; (at your option) any later version.
11 ; This program is distributed in the hope that it will be useful, but
12 ; WITHOUT ANY WARRANTY; without even the implied warranty of
13 ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 ; General Public License for more details.
17 ; ANSI control sequences
19 (defun move-to (col row)
20 (patom "\033[" row ";" col "H")
27 (defun display-string (x y str)
32 ; Here's the pieces to display
34 (setq stack '(" * " " *** " " ***** " " ******* " " ********* " "***********"))
36 ; Here's all of the stacks of pieces
37 ; This is generated when the program is run
41 ; Display one stack, clearing any
44 (defun display-stack (x y clear stack)
47 (display-string x y (car stack))
48 (display-stack x (1+ y) 0 (cdr stack))
53 (display-string x y " ")
54 (display-stack x (1+ y) (1- clear) stack)
59 ; Position of the top of the stack on the screen
60 ; Shorter stacks start further down the screen
62 (defun stack-pos (y stack)
66 ; Display all of the stacks, spaced 20 columns apart
68 (defun display-stacks (x y stacks)
70 (display-stack x 0 (stack-pos y (car stacks)) (car stacks))
71 (display-stacks (+ x 20) y (cdr stacks)))
75 ; Display all of the stacks, then move the cursor
76 ; out of the way and flush the output
79 (display-stacks 0 top stacks)
84 ; Reset stacks to the starting state, with
85 ; all of the pieces in the first stack and the
88 (defun reset-stacks ()
89 (setq stacks (list stack nil nil))
90 (setq top (+ (length stack) 3))
94 ; more functions which could usefully
103 ; Replace a stack in the list of stacks
106 (defun replace (list pos member)
107 (cond ((= pos 0) (cons member (cdr list)))
108 ((cons (car list) (replace (cdr list) (1- pos) member)))
112 ; Move a piece from the top of one stack
113 ; to the top of another
115 (setq move-delay 100)
117 (defun move-piece (from to)
118 (let ((from-stack (nth stacks from))
119 (to-stack (nth stacks to))
120 (piece (car from-stack)))
121 (setq from-stack (cdr from-stack))
122 (setq to-stack (cons piece to-stack))
123 (setq stacks (replace stacks from from-stack))
124 (setq stacks (replace stacks to to-stack))
130 ; The implementation of the game
132 (defun _hanoi (n from to use)
137 (_hanoi (1- n) from use to)
138 (_hanoi 1 from to use)
139 (_hanoi (1- n) use to from)
144 ; A pretty interface which
145 ; resets the state of the game,
146 ; clears the screen and runs
150 (setq len (reset-stacks))