example:Chess

This is the start of a chess game for RETRO.

It's based heavily on an earlier, two player system for Retro 11.

Begin a private namespace.

~~~{{  
~~~

Setup the default board.

We use an ASCII character for each piece.

| Char | Represents | | ---- | ---------- | | r | Rook | | n | Knight | | b | Bishop | | q | Queen | | k | King | | p | Pawn |

Lowercase is used for black pieces, UPPERCASE for white.

~~~  :str:, (s-) 
   [ , ] s:for-each ;  
  
  'Blank d:create 
  'rnbqkbnrpppppppp str:, 
  '................ str:, 
  '................ str:, 
  'PPPPPPPPRNBQKBNR str:, #0 , 
~~~

The default board (named Blank) won't be directly used. I create a second board for the actual gameplay.

~~~  'Board d:create 
  #64 allot  
~~~

Next up, the fundamentals of the display.

It'll display like this:

0_1_2_3_4_5_6_7 +-----------------+ 0 | r n b q k b n r | 1 | p p p p p p p p | 2 | . . . . . . . . | 3 | . . . . . . . . | 4 | . . . . . . . . | 5 | . . . . . . . . | 6 | P P P P P P P P | 7 | R N B Q K B N R | +-----------------+ 0_1_2_3_4_5_6_7

So first up, the columns.

~~~  :cols (-) 
    '____0_1_2_3_4_5_6_7 s:put nl ; 
~~~

Then a horizontal separator.

~~~  :--- (-)  
    '__+-----------------+ s:put nl ; 
~~~

And then a row.

Possible Future:

~~~  :row (a-a) 
    '%n_|_ s:format s:put 
    #8 [ fetch-next c:put sp ] times 
    $| c:put nl ; 
~~~

These will be tied together a little later into the top level display word.

~~~  :get (rc-a) swap #8 * &Board + + ; 
---reveal--- 
  :chess:display (-) 
    nl cols --- 
    &Board #0 row 
           #1 row 
           #2 row 
           #3 row 
           #4 row 
           #5 row 
           #6 row 
           #7 row drop 
    --- cols nl ; 
  :chess:new (-) 
    &Blank &Board #64 copy ; 
  :chess:move (rcrc-) 
    get [ get ] dip swap 
    dup fetch swap $. swap store 
    swap store ; 
~~~

Close the private namespace.

~~~}} 
~~~

~~~  chess:new 
  #0 #0 #2 #1 chess:move chess:display 
~~~