4 ms·

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 b

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 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...]

deleted 2y ago
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tslocum 2y ago
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 2y ago
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 https://pastebin.com/QeSdnQpM And the test cases I have for it: https://pastebin.com/vmMEjSMz https://pastebin.com/vmMEjSMz

deleted 2y ago

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tslocum 2y ago

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 2y ago

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