Author: Miguel A. Ballicora
Date: 16:49:45 07/11/01
Go up one level in this thread
On July 11, 2001 at 19:12:47, Dann Corbit wrote:
>On July 11, 2001 at 19:02:24, Bruce Moreland wrote:
>
>>On July 11, 2001 at 18:55:45, Dann Corbit wrote:
>>
>>>>As a consequence the FEN generated from such positions is not strictly
>>>>correct according to the standard from SJE, but IMO the standard should
>>>>be changed, here.
They are still correct IMHO. See below.
>>>
>>>Yes, I think the current PGN standard is broken in regard to e.p. squares.
I do not think is is broken, I think it is just ugly. I believe it has been
thought to allow certain programs to spit FENs in a faster/lazier way.
My interpretation is that the spirit is "one FEN determines a position, but a
position could be determined by different FENs"
After all, nobody will compare FEN databases in text mode to find duplicates...
or at least I guess that it was the idea.
be
>>>
>>>For instance, how many distinct positions is this:
>>>[D]rnbqkbnr/ppp1pppp/8/3p4/3P4/8/PPP1PPPP/RNBQKBNR w KQkq -
>>>You can make 4 of them, if you have to set e.p. flags, but there is only one
>>>real position. Multiply the number of potential pawns affected and it explodes
>>>with great stupidity.
>>
>>Wait a sec. Does the FEN standard according to SJE state that you *have* to
>>have the ep square set to e3 after 1. e4? If so, that is dumb and I'm going to
>>happily ignore it. The square shouldn't be set unless there is a legal capture,
>>or at least it should be optional to set it if there isn't.
>
>"16.1.3.4: En passant target square
>
>The fourth field is the en passant target square. If there is no en passant
>target square then the single character symbol "-" appears. If there is an en
>passant target square then is represented by a lowercase file character
>immediately followed by a rank digit. Obviously, the rank digit will be "3"
>following a white pawn double advance (Black is the active color) or else be
>the digit "6" after a black pawn double advance (White being the active color).
>
>An en passant target square is given if and only if the last move was a pawn
>advance of two squares. Therefore, an en passant target square field may have
^^^^^^^^
>a square name even if there is no pawn of the opposing side that may
>immediately execute the en passant capture."
Notice that it says "may have" rather than "must have".
Regards,
Miguel
>
>Notice the second paragraph.
>Ugh.
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