Date: Tue, 6 May 1997 01:58:58 -0400
From: Marcus Wickman <jens.yllman@mailbox.swipnet.se>
Subject: Re: SGF

At 20.02 1997-05-05 -0400, you wrote:
>
>On Mon, 5 May 1997, Jens Yllman wrote:
>
>>  I was just looking at the 'EBNF definition' of SGF. And there it says
>> 'GameTree = "(" Sequence { GameTree } ")"'. Does this mean that there
>> can not be any nodes between and after the GameTree? I know I sound
>
>Correct. No nodes in between gametrees.

 Ahhhh. Sorry. Sometimes when you're trying to hard you miss the obvious.

>
>> avoid the kind of trouble we've had with diffrent implimentations of SGF
>> before. And then we should be very clear of these things. So everybody
>> writes files everybody can read.
>
>The EBNF definition is clear - there are no ambiguities.
>Every programmer has seen EBNF defintions at least once.
>I don't plan to extend the description as everyone not able to understand 
>this widely used syntax shouldn't be allowed to program anyway.
>

 I understand the EBNF without problem. It was just that my brain
malfunctioned and I thougt that you want nodes in between. Sorry. Now when
you said no I know I made a misstake.

>>  I just have a small question to everybody. If the file you are about to
>> save does not contain anything that is new in SGF FF[4], should we save
>> it in a older version. I don't think so now, because I think we should
>
>FF[4] can be written in a FF[3] compatible way (and vice versa).
>Use 'tt' pass moves, no compressed point lists and no soft linebreaks.
>And of course no new properties (e.g arrow or line).
>It doesn't matter then, if you write 3 or 4 into the FF[] field.

 I was just fishing for what all you think when it comes to save the file
in a way older programs can read. I think you should save in a older
version if you can, or leave the choise to the user. The only thing when
saving in version older then FF[4] is to keep the style as close to FF[4]
as possible.

>
>>  Arno, does your program only convert from FF[1-3] to FF[4] or can it
>> check FF[4] files for errors? I only wonder if we can use it to verify
>> our programs.
>
>SGFC is intended to be the SGF reference implementation.
>
>SGFC knows all FF[4] properties and all FF[123] properties which were
>defined in Anders' theses (FF[1]) or Martin's web pages (FF[3]).
>
>SGFC checks almost all error conditions that can occur in a SGF file.
>Sometimes it even warns about bad style.
>
>SGFC is able to check/correct and convert FF[1]-FF[4] files.
>
>And yes, it may be used to very the output of your program.
>
>/Arno


 Jens Yllman