Part II — Organise the game¶
The board has already taught us an important boundary: drawing is a small, explicit adapter. Keep that boundary when the program gets larger.
tictactoe/
├── board.hal drawing commands and layout
├── game.hal pure state, rules, and win checking
└── main.hal ns+, frame input, and draw/render
board.hal says what to draw. game.hal decides what a move means. main.hal
is the only file that knows about the browser frame and the canvas capability.
The division is useful because the first two files can be read and tested as
ordinary data transformations.
Practical — name a boundary¶
Pick one command from the board page and decide where it belongs. A
[:line ...] board command belongs in board.hal; next-move belongs in
game.hal; draw/next-frame belongs in main.hal. If you are unsure, ask:
“does this need the browser, or only the game value?”