(hanoi): Don't show line and column numbers.

Compute height and width of the window in the correct way,
give the correct error message if the window is too small.
Make rings only with numerical characters.
Set default number of rings to 7 (was 3 before).

1 files changed, 23 insertions, 42 deletions

diff --git a/lisp/play/hanoi.el b/lisp/play/hanoi.el
index 12a700d458e..ba74a2ba645 100644
--- a/lisp/play/hanoi.el
+++ b/lisp/play/hanoi.el
@@ -53,59 +53,40 @@
 ;;;###autoload
 (defun hanoi (nrings)
   "Towers of Hanoi diversion.  Argument is number of rings."
-  (interactive
-   (list (if (null current-prefix-arg)
-             3
-             (prefix-numeric-value current-prefix-arg))))  
-  (if (<= nrings 0) (error "Negative number of rings"))
+  (interactive "p")
+  (if (<= nrings 1) (setq nrings 7))
   (let* (floor-row
          fly-row
-         (window-height (window-height (selected-window)))
+         (window-height (1- (window-height (selected-window))))
          (window-width (window-width (selected-window)))
 
-         ;; This is the unit of spacing to use between poles.  It
-         ;; must be even.  We round down, since rounding up might
-         ;; cause us to draw off the edge of the window.
-         (pole-spacing (logand (/ window-width 6) (lognot 1))))
-    (let (
-          ;; The poles are (1+ NRINGS) rows high; we also want an
-          ;; empty row at the top for the flying rings, a base, and a
-          ;; blank line underneath that.
-          (h (+ nrings 4))
-
-          ;; If we have NRINGS rings, we label them with the numbers 0
-          ;; through NRINGS-1.  The width of ring i is 2i+3; it pokes
-          ;; out i spaces on either side of the pole.  Rather than
-          ;; checking if the window is wide enough to accommodate this,
-          ;; we make sure pole-spacing is large enough, since that
-          ;; works even when we have decremented pole-spacing to make
-          ;; it even.
-          (w (1+ nrings)))
-      (if (not (and (>= window-height h)
-                    (> pole-spacing w)))
-          (progn
-            (delete-other-windows)
-            (if (not (and (>= (setq window-height
-                                    (window-height (selected-window)))
-                              h)
-                          (> (setq pole-spacing
-                                   (logand (/ window-width 6) (lognot 1)))
-                             w)))
-                (error "Screen is too small (need at least %dx%d)" w h))))
-      (setq floor-row (if (> (- window-height 3) h)
-                          (- window-height 3) window-height)))
+         ;; This is half the spacing to use between poles.
+         (pole-spacing (/ window-width 6)))
+    (if (not (and (> window-height (1+ nrings))
+                  (> pole-spacing nrings)))
+        (progn
+          (delete-other-windows)
+          (if (not (and (> (setq window-height
+                                 (1- (window-height (selected-window))))
+                           (1+ nrings))
+                        (> (setq pole-spacing (/ window-width 6))
+                           nrings)))
+              (error "Window is too small (need at least %dx%d)"
+                     (* 6 (1+ nrings)) (+ 2 nrings)))))
+    (setq floor-row (if (> (- window-height 3) (1+ nrings))
+                        (- window-height 3) window-height))
     (let ((fly-row (- floor-row nrings 1))
           ;; pole: column . fill height
-          (pole-1 (cons pole-spacing floor-row))
-          (pole-2 (cons (* 3 pole-spacing) floor-row))
-          (pole-3 (cons (* 5 pole-spacing) floor-row))
+          (pole-1 (cons (1- pole-spacing) floor-row))
+          (pole-2 (cons (1- (* 3 pole-spacing)) floor-row))
+          (pole-3 (cons (1- (* 5 pole-spacing)) floor-row))
           (rings (make-vector nrings nil)))
       ;; construct the ring list
       (let ((i 0))
         (while (< i nrings)
           ;; ring: [pole-number string empty-string]
           (aset rings i (vector nil
-                                (make-string (+ i i 3) (+ ?0 i))
+                                (make-string (+ i i 3) (+ ?0 (% i 10)))
                                 (make-string (+ i i 3) ?\  )))
           (setq i (1+ i))))
       ;;
@@ -124,7 +105,7 @@
 
       (let ((n 1))
         (while (< n 6)
-          (hanoi-topos fly-row (* n pole-spacing))
+          (hanoi-topos fly-row (1- (* n pole-spacing)))
           (setq n (+ n 2))
           (let ((i fly-row))
             (while (< i floor-row)