enter game notation - feature request & parse error

[BriCra17gh]

Would it be possible to relax the rules of PGN when entering a game? For example, allow "oo" or "00" for castling. Currently such notation is silently ignored or results in a non-intuitive error message, depending on the case.

Another example is allow lower case letters for minor/major pieces ("nxe4" for "Nxe4"). Currently the parser produces unexpected output from such input.

Here are examples (see bold for unexpected output):

In: 1. e4 e5 2. Nf3 Nc6 3. Bb5 Nf6 4. oo nxe4
Out: error popup displays "Invalid move. 4.e2e4"

In: 1. e4 e5 2. Nf3 Nc6 3. Bb5 Nf6 4. o-o nxe4
Out: 1. e4 e5 2. Nf3 Nc6 3. Bb5 Nf6 4. O-O exe4

In: 1. e4 e5 2. nf3
Out: 1. e4 e5 2. f3

BriCra

[gbtami]

You can find the pgn parser regexp in https://github.com/pychess/pychess/blob/master/lib/pychess/Savers/pgn.py
I think it's rather forgiving but if you can make it more relaxed go for it. Patches are welcome!

[BriCra17gh]

I would need to learn python in order to help. I might do that.

I'd like to try to make sure I expressed things clearly in my post. Aside from the feature request of non-standard notation, I was pointing out a few problems:

• an error message that does not reflect the error (ex. 1)
• changing non-standard input to an illegal move (ex. 2)
• changing non-standard input to a legal, but unintended move (ex. 3)

It seems to me that if non-standard input is disallowed, then the user should be informed of the erroneous input and that incorrect output should not be generated. What do you think?

[gbtami]

Agreed.