>>
: .BOARD ( -- )
0 5 AT-XY
0 BOARD
4 0 DO CR CR 33 SPACES
4 0 DO COUNT EMIT 3 SPACES
LOOP
LOOP DROP 7 SPACES ;
\ The player chooses the character to shift.
\ This is why the characters should be unique.
0 VALUE CHECK
: >CODE ( ch -- c ) DUP 32 AND - ; \ Upper? ( **)
: PLAYER ( -- ) KEY >CODE TO CHECK ;
\ Pos = position relative to SPOT. Take care of borders.
: WEST? ( -- pos ) SPOT 3 AND 0<> -1 AND ; ( **)
: EAST? ( -- pos ) SPOT 1+ 3 AND 0<> 1 AND ; ( **)
: NORTH? ( -- pos ) SPOT 3 > -4 AND ; ( **)
: SOUTH? ( -- pos ) SPOT 12 < 4 AND ; ( **)
: CHAR? ( pos -- pos ) \ The correct character?
DUP SPOT + BOARD C@ >CODE
CHECK = AND ; ( **)
: THERE ( -- index ) \ Position of character to shift
NORTH? CHAR?
WEST? CHAR? OR
EAST? CHAR? OR
SOUTH? CHAR? OR SPOT + ;
| V | I | J | G |
| E | B | L | A |
| D | * | F | O |
| R | T | H |
: SHIFT ( index -- )
DUP BOARD SPOT BOARD
OVER C@ OVER C@
-ROT
SWAP C! SWAP C!
TO SPOT ;
\ For CHOOSE see e.g. Brodie, SF.
: PLAY ( -- )
PAGE FINAL .BOARD 1997 MS
32 0
DO 15 CHOOSE SHIFT .BOARD
LOOP
BEGIN PLAYER THERE SHIFT .BOARD
CHECK 27 = \ Escape?
UNTIL ;