1 # Chessboard program: you type in moves in algebraic notation, and it'll
  2 # display the position after each move.
  3 
  4 def main [
  5   local-scope
  6   open-console  # take control of screen, keyboard and mouse
  7   clear-screen 0/screen  # non-scrolling app
  8 
  9   # The chessboard function takes keyboard and screen objects as 'ingredients'.
 10   #
 11   # In Mu it is good form (though not required) to explicitly state what
 12   # hardware a function needs.
 13   #
 14   # Here the console and screen are both 0, which usually indicates real
 15   # hardware rather than a fake for testing as you'll see below.
 16   chessboard 0/screen, 0/console
 17 
 18   close-console  # clean up screen, keyboard and mouse
 19 ]
 20 
 21 ## But enough about Mu. Here's what it looks like to run the chessboard program.
 22 
 23 scenario print-board-and-read-move [
 24   local-scope
 25   trace-until 100/app
 26   # we'll make the screen really wide because the program currently prints out a long line
 27   assume-screen 120/width, 20/height
 28   # initialize keyboard to type in a move
 29   assume-console [
 30   ¦ type [a2-a4
 31 ]
 32   ]
 33   run [
 34   ¦ screen:&:screen, console:&:console <- chessboard screen:&:screen, console:&:console
 35   ¦ # icon for the cursor
 36   ¦ cursor-icon:char <- copy 9251/␣
 37   ¦ screen <- print screen, cursor-icon
 38   ]
 39   screen-should-contain [
 40   #            1         2         3         4         5         6         7         8         9         10        11
 41   #  012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789
 42   ¦ .Stupid text-mode chessboard. White pieces in uppercase; black pieces in lowercase. No checking for legal moves.         .
 43   ¦ .                                                                                                                        .
 44   ¦ .8 | r n b q k b n r                                                                                                     .
 45   ¦ .7 | p p p p p p p p                                                                                                     .
 46   ¦ .6 |                                                                                                                     .
 47   ¦ .5 |                                                                                                                     .
 48   ¦ .4 | P                                                                                                                   .
 49   ¦ .3 |                                                                                                                     .
 50   ¦ .2 |   P P P P P P P                                                                                                     .
 51   ¦ .1 | R N B Q K B N R                                                                                                     .
 52   ¦ .  +----------------                                                                                                     .
 53   ¦ .    a b c d e f g h                                                                                                     .
 54   ¦ .                                                                                                                        .
 55   ¦ .Type in your move as <from square>-<to square>. For example: 'a2-a4'. Then press <enter>.                               .
 56   ¦ .                                                                                                                        .
 57   ¦ .Hit 'q' to exit.                                                                                                        .
 58   ¦ .                                                                                                                        .
 59   ¦ .move: ␣                                                                                                                 .
 60   ¦ .                                                                                                                        .
 61   ¦ .                                                                                                                        .
 62   ]
 63 ]
 64 
 65 ## Here's how 'chessboard' is implemented.
 66 
 67 type board = &:@:&:@:char  # a 2-D array of arrays of characters
 68 
 69 def chessboard screen:&:screen, console:&:console -> screen:&:screen, console:&:console [
 70   local-scope
 71   load-ingredients
 72   board:board <- initial-position
 73   # hook up stdin
 74   stdin-in:&:source:char, stdin-out:&:sink:char <- new-channel 10/capacity
 75   start-running send-keys-to-channel, console, stdin-out, screen
 76   # buffer lines in stdin
 77   buffered-stdin-in:&:source:char, buffered-stdin-out:&:sink:char <- new-channel 10/capacity
 78   start-running buffer-lines, stdin-in, buffered-stdin-out
 79   {
 80   ¦ print screen, [Stupid text-mode chessboard. White pieces in uppercase; black pieces in lowercase. No checking for legal moves.
 81 ]
 82   ¦ cursor-to-next-line screen
 83   ¦ print-board screen, board
 84   ¦ cursor-to-next-line screen
 85   ¦ print screen, [Type in your move as <from square>-<to square>. For example: 'a2-a4'. Then press <enter>.
 86 ]
 87   ¦ cursor-to-next-line screen
 88   ¦ print screen [Hit 'q' to exit.
 89 ]
 90   ¦ {
 91   ¦ ¦ cursor-to-next-line screen
 92   ¦ ¦ screen <- print screen, [move: ]
 93   ¦ ¦ m:&:move, quit:bool, error:bool <- read-move buffered-stdin-in, screen
 94   ¦ ¦ break-if quit, +quit
 95   ¦ ¦ buffered-stdin-in <- clear buffered-stdin-in  # cleanup after error. todo: test this?
 96   ¦ ¦ loop-if error
 97   ¦ }
 98   ¦ board <- make-move board, m
 99   ¦ screen <- clear-screen screen
100   ¦ loop
101   }
102   +quit
103 ]
104 
105 ## a board is an array of files, a file is an array of characters (squares)
106 
107 def new-board initial-position:&:@:char -> board:board [
108   local-scope
109   load-ingredients
110   # assert(length(initial-position) == 64)
111   len:num <- length *initial-position
112   correct-length?:bool <- equal len, 64
113   assert correct-length?, [chessboard had incorrect size]
114   # board is an array of pointers to files; file is an array of characters
115   board <- new {(address array character): type}, 8
116   col:num <- copy 0
117   {
118   ¦ done?:bool <- equal col, 8
119   ¦ break-if done?
120   ¦ file:&:@:char <- new-file initial-position, col
121   ¦ *board <- put-index *board, col, file
122   ¦ col <- add col, 1
123   ¦ loop
124   }
125 ]
126 
127 def new-file position:&:@:char, index:num -> result:&:@:char [
128   local-scope
129   load-ingredients
130   index <- multiply index, 8
131   result <- new character:type, 8
132   row:num <- copy 0
133   {
134   ¦ done?:bool <- equal row, 8
135   ¦ break-if done?
136   ¦ square:char <- index *position, index
137   ¦ *result <- put-index *result, row, square
138   ¦ row <- add row, 1
139   ¦ index <- add index, 1
140   ¦ loop
141   }
142 ]
143 
144 def print-board screen:&:screen, board:board -> screen:&:screen [
145   local-scope
146   load-ingredients
147   row:num <- copy 7  # start printing from the top of the board
148   space:char <- copy 32/space
149   # print each row
150   {
151   ¦ done?:bool <- lesser-than row, 0
152   ¦ break-if done?
153   ¦ # print rank number as a legend
154   ¦ rank:num <- add row, 1
155   ¦ print screen, rank
156   ¦ print screen, [ | ]
157   ¦ # print each square in the row
158   ¦ col:num <- copy 0
159   ¦ {
160   ¦ ¦ done?:bool <- equal col:num, 8
161   ¦ ¦ break-if done?:bool
162   ¦ ¦ f:&:@:char <- index *board, col
163   ¦ ¦ c:char <- index *f, row
164   ¦ ¦ print screen, c
165   ¦ ¦ print screen, space
166   ¦ ¦ col <- add col, 1
167   ¦ ¦ loop
168   ¦ }
169   ¦ row <- subtract row, 1
170   ¦ cursor-to-next-line screen
171   ¦ loop
172   }
173   # print file letters as legend
174   print screen, [  +----------------]
175   cursor-to-next-line screen
176   print screen, [    a b c d e f g h]
177   cursor-to-next-line screen
178 ]
179 
180 def initial-position -> board:board [
181   local-scope
182   # layout in memory (in raster order):
183   #   R P _ _ _ _ p r
184   #   N P _ _ _ _ p n
185   #   B P _ _ _ _ p b
186   #   Q P _ _ _ _ p q
187   #   K P _ _ _ _ p k
188   #   B P _ _ _ _ p B
189   #   N P _ _ _ _ p n
190   #   R P _ _ _ _ p r
191   initial-position:&:@:char <- new-array 82/R, 80/P, 32/blank, 32/blank, 32/blank, 32/blank, 112/p, 114/r, 78/N, 80/P, 32/blank, 32/blank, 32/blank, 32/blank, 112/p, 110/n, 66/B, 80/P, 32/blank, 32/blank, 32/blank, 32/blank, 112/p, 98/b, 81/Q, 80/P, 32/blank, 32/blank, 32/blank, 32/blank, 112/p, 113/q, 75/K, 80/P, 32/blank, 32/blank, 32/blank, 32/blank, 112/p, 107/k, 66/B, 80/P, 32/blank, 32/blank, 32/blank, 32/blank, 112/p, 98/b, 78/N, 80/P, 32/blank, 32/blank, 32/blank, 32/blank, 112/p, 110/n, 82/R, 80/P, 32/blank, 32/blank, 32/blank, 32/blank, 112/p, 114/r
192 #?       82/R, 80/P, 32/blank, 32/blank, 32/blank, 32/blank, 112/p, 114/r,
193 #?       78/N, 80/P, 32/blank, 32/blank, 32/blank, 32/blank, 112/p, 110/n,
194 #?       66/B, 80/P, 32/blank, 32/blank, 32/blank, 32/blank, 112/p, 98/b, 
195 #?       81/Q, 80/P, 32/blank, 32/blank, 32/blank, 32/blank, 112/p, 113/q,
196 #?       75/K, 80/P, 32/blank, 32/blank, 32/blank, 32/blank, 112/p, 107/k,
197 #?       66/B, 80/P, 32/blank, 32/blank, 32/blank, 32/blank, 112/p, 98/b,
198 #?       78/N, 80/P, 32/blank, 32/blank, 32/blank, 32/blank, 112/p, 110/n,
199 #?       82/R, 80/P, 32/blank, 32/blank, 32/blank, 32/blank, 112/p, 114/r
200   board <- new-board initial-position
201 ]
202 
203 scenario printing-the-board [
204   local-scope
205   board:board <- initial-position
206   assume-screen 30/width, 12/height
207   run [
208   ¦ screen:&:screen <- print-board screen:&:screen, board
209   ]
210   screen-should-contain [
211   #  012345678901234567890123456789
212   ¦ .8 | r n b q k b n r           .
213   ¦ .7 | p p p p p p p p           .
214   ¦ .6 |                           .
215   ¦ .5 |                           .
216   ¦ .4 |                           .
217   ¦ .3 |                           .
218   ¦ .2 | P P P P P P P P           .
219   ¦ .1 | R N B Q K B N R           .
220   ¦ .  +----------------           .
221   ¦ .    a b c d e f g h           .
222   ¦ .                              .
223   ¦ .                              .
224   ]
225 ]
226 
227 ## data structure: move
228 
229 container move [
230   # valid range: 0-7
231   from-file:num
232   from-rank:num
233   to-file:num
234   to-rank:num
235 ]
236 
237 # prints only error messages to screen
238 def read-move stdin:&:source:char, screen:&:screen -> result:&:move, quit?:bool, error?:bool, stdin:&:source:char, screen:&:screen [
239   local-scope
240   load-ingredients
241   from-file:num, quit?:bool, error?:bool <- read-file stdin, screen
242   return-if quit?, 0/dummy
243   return-if error?, 0/dummy
244   # construct the move object
245   result:&:move <- new move:type
246   *result <- put *result, from-file:offset, from-file
247   from-rank:num, quit?, error? <- read-rank stdin, screen
248   return-if quit?, 0/dummy
249   return-if error?, 0/dummy
250   *result <- put *result, from-rank:offset, from-rank
251   error? <- expect-from-channel stdin, 45/dash, screen
252   return-if error?, 0/dummy, 0/quit
253   to-file:num, quit?, error? <- read-file stdin, screen
254   return-if quit?:bool, 0/dummy
255   return-if error?:bool, 0/dummy
256   *result <- put *result, to-file:offset, to-file
257   to-rank:num, quit?, error? <- read-rank stdin, screen
258   return-if quit?, 0/dummy
259   return-if error?, 0/dummy
260   *result <- put *result, to-rank:offset, to-rank
261   error? <- expect-from-channel stdin, 10/newline, screen
262   return-if error?, 0/dummy, 0/quit
263 ]
264 
265 # valid values for file: 0-7
266 def read-file stdin:&:source:char, screen:&:screen -> file:num, quit:bool, error:bool, stdin:&:source:char, screen:&:screen [
267   local-scope
268   load-ingredients
269   c:char, eof?:bool, stdin <- read stdin
270   return-if eof?, 0/dummy, 1/quit, 0/error
271   {
272   ¦ q-pressed?:bool <- equal c, 81/Q
273   ¦ break-unless q-pressed?
274   ¦ return 0/dummy, 1/quit, 0/error
275   }
276   {
277   ¦ q-pressed? <- equal c, 113/q
278   ¦ break-unless q-pressed?
279   ¦ return 0/dummy, 1/quit, 0/error
280   }
281   {
282   ¦ empty-fake-keyboard?:bool <- equal c, 0/eof
283   ¦ break-unless empty-fake-keyboard?
284   ¦ return 0/dummy, 1/quit, 0/error
285   }
286   {
287   ¦ newline?:bool <- equal c, 10/newline
288   ¦ break-unless newline?
289   ¦ print screen, [that's not enough]
290   ¦ return 0/dummy, 0/quit, 1/error
291   }
292   file:num <- subtract c, 97/a
293   # 'a' <= file <= 'h'
294   {
295   ¦ above-min:bool <- greater-or-equal file, 0
296   ¦ break-if above-min
297   ¦ print screen, [file too low: ]
298   ¦ print screen, c
299   ¦ cursor-to-next-line screen
300   ¦ return 0/dummy, 0/quit, 1/error
301   }
302   {
303   ¦ below-max:bool <- lesser-than file, 8
304   ¦ break-if below-max
305   ¦ print screen, [file too high: ]
306   ¦ print screen, c
307   ¦ return 0/dummy, 0/quit, 1/error
308   }
309   return file, 0/quit, 0/error
310 ]
311 
312 # valid values for rank: 0-7
313 def read-rank stdin:&:source:char, screen:&:screen -> rank:num, quit?:bool, error?:bool, stdin:&:source:char, screen:&:screen [
314   local-scope
315   load-ingredients
316   c:char, eof?:bool, stdin <- read stdin
317   return-if eof?, 0/dummy, 1/quit, 0/error
318   {
319   ¦ q-pressed?:bool <- equal c, 8/Q
320   ¦ break-unless q-pressed?
321   ¦ return 0/dummy, 1/quit, 0/error
322   }
323   {
324   ¦ q-pressed? <- equal c, 113/q
325   ¦ break-unless q-pressed?
326   ¦ return 0/dummy, 1/quit, 0/error
327   }
328   {
329   ¦ newline?:bool <- equal c, 10  # newline
330   ¦ break-unless newline?
331   ¦ print screen, [that's not enough]
332   ¦ return 0/dummy, 0/quit, 1/error
333   }
334   rank:num <- subtract c, 49/'1'
335   # assert'1' <= rank <= '8'
336   {
337   ¦ above-min:bool <- greater-or-equal rank, 0
338   ¦ break-if above-min
339   ¦ print screen, [rank too low: ]
340   ¦ print screen, c
341   ¦ return 0/dummy, 0/quit, 1/error
342   }
343   {
344   ¦ below-max:bool <- lesser-or-equal rank, 7
345   ¦ break-if below-max
346   ¦ print screen, [rank too high: ]
347   ¦ print screen, c
348   ¦ return 0/dummy, 0/quit, 1/error
349   }
350   return rank, 0/quit, 0/error
351 ]
352 
353 # read a character from the given channel and check that it's what we expect
354 # return true on error
355 def expect-from-channel stdin:&:source:char, expected:char, screen:&:screen -> result:bool, stdin:&:source:char, screen:&:screen [
356   local-scope
357   load-ingredients
358   c:char, eof?:bool, stdin <- read stdin
359   return-if eof? 1/true
360   {
361   ¦ match?:bool <- equal c, expected
362   ¦ break-if match?
363   ¦ print screen, [expected character not found]
364   }
365   result <- not match?
366 ]
367 
368 scenario read-move-blocking [
369   local-scope
370   assume-screen 20/width, 2/height
371   source:&:source:char, sink:&:sink:char <- new-channel 2/capacity
372   read-move-routine:num/routine <- start-running read-move, source, screen:&:screen
373   run [
374   ¦ # 'read-move' is waiting for input
375   ¦ wait-for-routine-to-block read-move-routine
376   ¦ read-move-state:num <- routine-state read-move-routine
377   ¦ waiting?:bool <- not-equal read-move-state, 2/discontinued
378   ¦ assert waiting?, [ 
379 F read-move-blocking: routine failed to pause after coming up (before any keys were pressed)]
380   ¦ # press 'a'
381   ¦ sink <- write sink, 97/a
382   ¦ restart read-move-routine
383   ¦ # 'read-move' still waiting for input
384   ¦ wait-for-routine-to-block read-move-routine
385   ¦ read-move-state <- routine-state read-move-routine
386   ¦ waiting? <- not-equal read-move-state, 2/discontinued
387   ¦ assert waiting?, [ 
388 F read-move-blocking: routine failed to pause after rank 'a']
389   ¦ # press '2'
390   ¦ sink <- write sink, 50/'2'
391   ¦ restart read-move-routine
392   ¦ # 'read-move' still waiting for input
393   ¦ wait-for-routine-to-block read-move-routine
394   ¦ read-move-state <- routine-state read-move-routine
395   ¦ waiting? <- not-equal read-move-state, 2/discontinued
396   ¦ assert waiting?, [ 
397 F read-move-blocking: routine failed to pause after file 'a2']
398   ¦ # press '-'
399   ¦ sink <- write sink, 45/'-'
400   ¦ restart read-move-routine
401   ¦ # 'read-move' still waiting for input
402   ¦ wait-for-routine-to-block read-move-routine
403   ¦ read-move-state <- routine-state read-move-routine
404   ¦ waiting? <- not-equal read-move-state, 2/discontinued
405   ¦ assert waiting?, [ 
406 F read-move-blocking: routine failed to pause after hyphen 'a2-']
407   ¦ # press 'a'
408   ¦ sink <- write sink, 97/a
409   ¦ restart read-move-routine
410   ¦ # 'read-move' still waiting for input
411   ¦ wait-for-routine-to-block read-move-routine
412   ¦ read-move-state <- routine-state read-move-routine
413   ¦ waiting? <- not-equal read-move-state, 2/discontinued
414   ¦ assert waiting?, [ 
415 F read-move-blocking: routine failed to pause after rank 'a2-a']
416   ¦ # press '4'
417   ¦ sink <- write sink, 52/'4'
418   ¦ restart read-move-routine
419   ¦ # 'read-move' still waiting for input
420   ¦ wait-for-routine-to-block read-move-routine
421   ¦ read-move-state <- routine-state read-move-routine
422   ¦ waiting? <- not-equal read-move-state, 2/discontinued
423   ¦ assert waiting?, [ 
424 F read-move-blocking: routine failed to pause after file 'a2-a4']
425   ¦ # press 'newline'
426   ¦ sink <- write sink, 10  # newline
427   ¦ restart read-move-routine
428   ¦ # 'read-move' now completes
429   ¦ wait-for-routine-to-block read-move-routine
430   ¦ read-move-state <- routine-state read-move-routine
431   ¦ completed?:bool <- equal read-move-state, 1/completed
432   ¦ assert completed?, [ 
433 F read-move-blocking: routine failed to terminate on newline]
434   ¦ trace 1, [test], [reached end]
435   ]
436   trace-should-contain [
437   ¦ test: reached end
438   ]
439 ]
440 
441 scenario read-move-quit [
442   local-scope
443   assume-screen 20/width, 2/height
444   source:&:source:char, sink:&:sink:char <- new-channel 2/capacity
445   read-move-routine:num <- start-running read-move, source, screen:&:screen
446   run [
447   ¦ # 'read-move' is waiting for input
448   ¦ wait-for-routine-to-block read-move-routine
449   ¦ read-move-state:num <- routine-state read-move-routine
450   ¦ waiting?:bool <- not-equal read-move-state, 2/discontinued
451   ¦ assert waiting?, [ 
452 F read-move-quit: routine failed to pause after coming up (before any keys were pressed)]
453   ¦ # press 'q'
454   ¦ sink <- write sink, 113/q
455   ¦ restart read-move-routine
456   ¦ # 'read-move' completes
457   ¦ wait-for-routine-to-block read-move-routine
458   ¦ read-move-state <- routine-state read-move-routine
459   ¦ completed?:bool <- equal read-move-state, 1/completed
460   ¦ assert completed?, [ 
461 F read-move-quit: routine failed to terminate on 'q']
462   ¦ trace 1, [test], [reached end]
463   ]
464   trace-should-contain [
465   ¦ test: reached end
466   ]
467 ]
468 
469 scenario read-move-illegal-file [
470   local-scope
471   assume-screen 20/width, 2/height
472   source:&:source:char, sink:&:sink:char <- new-channel 2/capacity
473   read-move-routine:num <- start-running read-move, source, screen:&:screen
474   run [
475   ¦ # 'read-move' is waiting for input
476   ¦ wait-for-routine-to-block read-move-routine
477   ¦ read-move-state:num <- routine-state read-move-routine
478   ¦ waiting?:bool <- not-equal read-move-state, 2/discontinued
479   ¦ assert waiting?, [ 
480 F read-move-illegal-file: routine failed to pause after coming up (before any keys were pressed)]
481   ¦ sink <- write sink, 50/'2'
482   ¦ restart read-move-routine
483   ¦ wait-for-routine-to-block read-move-routine
484   ]
485   screen-should-contain [
486   ¦ .file too low: 2     .
487   ¦ .                    .
488   ]
489 ]
490 
491 scenario read-move-illegal-rank [
492   local-scope
493   assume-screen 20/width, 2/height
494   source:&:source:char, sink:&:sink:char <- new-channel 2/capacity
495   read-move-routine:num <- start-running read-move, source, screen:&:screen
496   run [
497   ¦ # 'read-move' is waiting for input
498   ¦ wait-for-routine-to-block read-move-routine
499   ¦ read-move-state:num <- routine-state read-move-routine
500   ¦ waiting?:bool <- not-equal read-move-state, 2/discontinued
501   ¦ assert waiting?, [ 
502 F read-move-illegal-rank: routine failed to pause after coming up (before any keys were pressed)]
503   ¦ sink <- write sink, 97/a
504   ¦ sink <- write sink, 97/a
505   ¦ restart read-move-routine
506   ¦ wait-for-routine-to-block read-move-routine
507   ]
508   screen-should-contain [
509   ¦ .rank too high: a    .
510   ¦ .                    .
511   ]
512 ]
513 
514 scenario read-move-empty [
515   local-scope
516   assume-screen 20/width, 2/height
517   source:&:source:char, sink:&:sink:char <- new-channel 2/capacity
518   read-move-routine:num <- start-running read-move, source, screen:&:screen
519   run [
520   ¦ # 'read-move' is waiting for input
521   ¦ wait-for-routine-to-block read-move-routine
522   ¦ read-move-state:num <- routine-state read-move-routine
523   ¦ waiting?:bool <- not-equal read-move-state, 2/discontinued
524   ¦ assert waiting?, [ 
525 F read-move-empty: routine failed to pause after coming up (before any keys were pressed)]
526   ¦ sink <- write sink, 10/newline
527   ¦ sink <- write sink, 97/a
528   ¦ restart read-move-routine
529   ¦ wait-for-routine-to-block read-move-routine
530   ]
531   screen-should-contain [
532   ¦ .that's not enough   .
533   ¦ .                    .
534   ]
535 ]
536 
537 def make-move board:board, m:&:move -> board:board [
538   local-scope
539   load-ingredients
540   from-file:num <- get *m, from-file:offset
541   from-rank:num <- get *m, from-rank:offset
542   to-file:num <- get *m, to-file:offset
543   to-rank:num <- get *m, to-rank:offset
544   from-f:&:@:char <- index *board, from-file
545   to-f:&:@:char <- index *board, to-file
546   src:char/square <- index *from-f, from-rank
547   *to-f <- put-index *to-f, to-rank, src
548   *from-f <- put-index *from-f, from-rank, 32/space
549 ]
550 
551 scenario making-a-move [
552   local-scope
553   assume-screen 30/width, 12/height
554   board:board <- initial-position
555   move:&:move <- new move:type
556   *move <- merge 6/g, 1/'2', 6/g, 3/'4'
557   run [
558   ¦ board <- make-move board, move
559   ¦ screen:&:screen <- print-board screen:&:screen, board
560   ]
561   screen-should-contain [
562   #  012345678901234567890123456789
563   ¦ .8 | r n b q k b n r           .
564   ¦ .7 | p p p p p p p p           .
565   ¦ .6 |                           .
566   ¦ .5 |                           .
567   ¦ .4 |             P             .
568   ¦ .3 |                           .
569   ¦ .2 | P P P P P P   P           .
570   ¦ .1 | R N B Q K B N R           .
571   ¦ .  +----------------           .
572   ¦ .    a b c d e f g h           .
573   ¦ .                              .
574   ]
575 ]