[closedl00p]

Hi, nice snappy interface (even after making the HN front page...) and I like the gentle highlighting of possible moves for a piece.

In two games against the bot I _think_ I had the luck to run into a corner case bug with the rules engine: in the position shown in this screenshot https://ibb.co/dQ3HsM4 I'd rolled a 4-6, but the UI would not let me move my piece on 9 four spaces to hit the opponent on 5 -- the UI only wanted to let me move that piece six spaces.

I can imagine how this bug could happen-- all my pieces except this one are in my inner table, so it looks like my piece on 9 is the only piece that can legally use the rolled six, and you're required to fully use your roll if possible... except in this particular case, once I move that piece four spots, I'd be fully in my inner table and could use the six to bear off a piece.

[sidenote: I realize I don't know the best 2024 way to host a temporary image for posting on a text-only forum like HN... but imgbb looked reasonable...]

[tslocum]

Thanks for reporting this and including a screenshot. I appreciate it.

I've just resolved this on the server and in the web client (now v1.3.5p1, displayed at the lower right when the game loads).

[dumbo-octopus]

While we're on the topic of ancient link-based sharing websites, here's a pastebin of the Typescript code I wrote years ago that I just dug up to see if it'd handle this case. It does! It uses an actually-pretty-fast backtracking implementation to check for valid moves - validating Backgammon moves is a harder problem than you'd think, especially doing so quickly enough to effectively run monte tree search with. Even with all the thought I've put into it, I still don't have a quick explanation I can give a human trying to learn that game what the valid moves are, especially in the endgame and with blocked moves.

https://pastebin.com/QeSdnQpM

And the test cases I have for it: https://pastebin.com/vmMEjSMz