master ca6c8fc72c 1/2: Allow different randomization of shapes in Tetris

[Lars Ingebrigtsen]

branch: master
commit ca6c8fc72c66c7ed997801e055e5fb25374d69b5
Author: Timothee Denizou <timothee.denizou@epita.fr>
Commit: Lars Ingebrigtsen <larsi@gnus.org>

    Allow different randomization of shapes in Tetris
    
    * lisp/play/tetris.el (tetris-allow-repetitions): New user option.
    (tetris--shuffle, tetris--seven-bag): New functions.
    (tetris-new-shape): Use the option.
    
    * Added 7 bag randomizer for tetris
    A piece is selected from the bag and removed each time we want a piece
    When the bag is empty, refill the bag with the seven piece and shuffle it
    
    Copyright-paperwork-exempt: yes
---
 lisp/play/tetris.el | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/lisp/play/tetris.el b/lisp/play/tetris.el
index 8ce2453c75..af1004e081 100644
--- a/lisp/play/tetris.el
+++ b/lisp/play/tetris.el
@@ -117,6 +117,13 @@ If the return value is a number, it is used as the timer 
period."
   "Y position of top left of playing area."
   :type 'number)
 
+(defcustom tetris-allow-repetitions t
+  "If non-nil, use a random selection for each shape.
+If nil, put the shapes into a bag and select without putting
+back (until empty, when the bag is repopulated."
+  :type 'boolean
+  :version "29.1")
+
 (defvar tetris-next-x (+ (* 2 tetris-top-left-x) tetris-width)
   "X position of next shape.")
 
@@ -233,6 +240,7 @@ each one of its four blocks.")
 (defvar-local tetris-pos-x 0)
 (defvar-local tetris-pos-y 0)
 (defvar-local tetris-paused nil)
+(defvar-local tetris--bag nil)
 
 ;; ;;;;;;;;;;;;; keymaps ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
@@ -341,10 +349,23 @@ each one of its four blocks.")
   (let ((period (tetris-get-tick-period)))
     (if period (gamegrid-set-timer period))))
 
+(defun tetris--shuffle (sequence)
+  (cl-loop for i from (length sequence) downto 2
+           do (cl-rotatef (elt sequence (random i))
+                          (elt sequence (1- i))))
+  sequence)
+
+(defun tetris--seven-bag ()
+  (when (not tetris--bag)
+    (setq tetris--bag (tetris--shuffle (list 0 1 2 3 4 5 6))))
+  (pop tetris--bag))
+
 (defun tetris-new-shape ()
   (setq tetris-shape tetris-next-shape)
   (setq tetris-rot 0)
-  (setq tetris-next-shape (random 7))
+  (setq tetris-next-shape (if tetris-allow-repetitions
+                              (tetris--seven-bag)
+                            (random 7)))
   (setq tetris-pos-x (/ (- tetris-width (tetris-shape-width)) 2))
   (setq tetris-pos-y 0)
   (if (tetris-test-shape)