Adding a checkpoint system? (Related to #51)

[Fittiboy]

I was browsing around for other daily puzzles to do, and on this website I discovered puzzles with a checkpoint system (hidden behind "Show checkpoints" in the little settings wheel at the top). I like the way it's implemented, and I've been thinking about how useful this would be for hexapipes.

When a daily is particularly difficult, I like to do some exploratory locking of promising tiles to see if I reach a contradiction to rule out one of their sometimes only two possible orientations. It's dangerous to lock and unlock tiles like this, because I might lose track of which tiles are genuinely locked, and which ones just have an exploratory temporary lock.

A checkpoint system would take care of this, without necessarily having to do a full undo/redo stack. A complete state is stored as-is and then simply restored whenever the user wishes. The timer should of course remain untouched!

I saw that it was mentioned here, but feel like it deserves its own issue.

[gereleth]

May 22 octagonal was brutal, wasn't it? =)

The problem I usually have with checkpoints on that site is that by the time I find a contradiction I've already forgotten my initial assumption. Then it's like - ok, state restored but what exactly did I learn? 🤔 So some indication of how the trial started could be really helpful too.

I have undo/redo stack implemented somewhere in an unpublished branch, maybe I'll have some free time to finish that in a month or two. Then I'll think about checkpoints as well, thanks for the suggestion =).

[Fittiboy]

May 22 octagonal was brutal, wasn't it? =)

Haha exactly why I opened this issue!

by the time I find a contradiction I've already forgotten my initial assumption.

I'm the kind of person to just write it down on a notepad in front of me, but an actual solution could be to highlight the first change made after creating a checkpoint.
Say I create a new checkpoint and then lock a tile and later find a contradiction. Then I load the checkpoint, and the tile I first locked gets highlighted.

Having an undo/redo stack would also be amazing!