aebletrae [she/her]

But those kinds of initialisations belong in .profile (or, if you’re using a weird desktop environment, its own configuration file), particularly if you want .desktop files to work. (In .bashrc, PATH will grow longer in each subshell, which shouldn’t cause problems but is wasteful.)

So, what desktop environment (GNOME, KDE, Cinnamon, etc.) are you using?

.profile is executed by login shells for the benefit of it and its subshells, and by DEs like Cinnamon for the benefit of .desktop launchers at login.

So, have you logged out and back in again since adding these lines to .profile?

And of course, the .profile has to be executed properly for its configuration to take effect, so it`s useful to know if the problem is with those specific lines, or the file as a whole.

Add:—

date >> ~/profile-execution-log-top.txt
echo $PATH >> ~/profile-execution-log-top.txt

to the top of .profile, and:—

date >> ~/profile-execution-log-end.txt
echo $PATH >> ~/profile-execution-log-end.txt

to the bottom of .profile (use alternative paths as you see fit) to monitor that activity. You can test this by sourcing .profile but the real test is logging out and in again. Look at the time when you do this so you can correlate each action with each timestamp in the log files. If .profile is executed to completion, you should have two files with matching timestamps but different PATHs. If you don’t have a matching timestamp in the “end” log file, there’s a problem mid-execution. If neither file is being updated, .profile isn’t being executed at all.

Since .bashrc is executed for all non-login shells, it shouldn’t really source .profile, which is only meant for login shells, and might trigger expensive activity. (.profile might source .bashrc, but that`s fine.)

Are other lines in .profile being executed, or is the whole file ignored? Have you logged out and in again since adding these lines?

Ah, Enhanced, the folks that brought us interrogation.

Having thought about this some more with practicality and clarity thrown out the window in favour of abstractions, how about this?

A game is a sequence of moves. Past moves are immutable, future moves unknowable; a singly linked list fits the bill here.

Each move consists of a player token and a position. The position might ordinarily be thought of as a grid index but, as you point out, it could just as well be membership in one of the potentially winning lines. Either a move is part of one of these lines or it isn’t. This makes the position equivalent to a bit field. If each potential win line is distinct, they could indeed be held sparsely in a set.

Checking for a win then consists of counting player tokens for each potential win line and checking for crossing the necessary threshold. Filter, sum, max, greater than?, any?

I think this scheme would be applicable to arbitrary game boards, with none of it requiring mutation. Is that the kind of thing you were after? The reflection/rotation equivalence isn’t present here, but I still think that’s more an artefact of analysis, rather than a property of gameplay.

2. The ordering of each row should not matter.

This is true for your abstracted rows, but is maintaining eight sets of three square states, two or three of which must be updated with every move, really a better model than a single sequence of nine, where only one needs to change at a time? It’s more complex to think about, and is less efficient to update. When you throw in steps to canonicalize the rotation and reflection, which may produce different transformations from the input/output grid on the first three moves, you may need to change even more set items with each move.

It’s true that, mathematically, the mapping from grid to sequence is arbitrary and the only thing that matters is consistency, but if you view programming languages as a way to communicate with humans, then clarity of purpose, rather than mathematical idealism, should be your goal. Use a nine-item array or a three-by-three nested array for the underlying storage and treat your eight win-checking sets as views into that more ordered structure. These views could well be functions that return a set and are themselves held in a set to be applied in any order. Similarly, treat canonicalization as another way to view the underlying board.

You could sidestep the mutable borrowing by not mutating individual squares. Take a leaf from the functional-programming books and use a function that takes a board and a move and returns an entirely new board. Or takes a board and returns one of the abstracted row sets. There are only nine squares and nine moves. The win-checking views aren’t needed before move six. A bit of copying isn’t going be a problem.