Date: Mon, 9 Jun 1997 10:55:36 -0400 From: Rene Grothmann Subject: SGF complaints Having just finished a major SGF viewer (Jago), I am now studying the FF[4] standards to make get my program in line. After first sight, I have several complains about these standards. Most of my complains are due to my design decision to use the SGF format as an internal format to hold the game tree. But this is effectively prevented by the structure of the format. So I will have either to rewrite the code and filter on input and output, or to hack around with internal tags. I welcome comments on this. Here are my complaints in detail: - The M tag is supported and used by each and every viewer I know. Most won't even recognize the MA replacement (which should rather be the SQ replacement). Taking it out of the standard is an annoyance. There must be very good excuses to create that much incompatibility. - The same applies to the L tag. I see that the LB tag is better in many ways. However, they could both coexist, using different colors in the viewer if necessary. Again not supporting it is an annoyance. - AB, AW and AE are not revertable. Thus you cannot play a tree upwards with known end position but must record the true meaning of AB, AW and especially AE. I suggest to allow AB and AW only on empty positions, and replace AE by CB (clear black) and CW (clear white) or something else available. This suggestion would clearly cause incompatibilities too. But in this case, it is well worth it. - The SGF checker SGFC complains about splitted AE commands. Though this attempt to stay logical is to be appreciated, it is an annoyance. Tags should be applied as they appear. Any viewer can warn the user about redundand addings and removals or such. Moreover, there is still no predefined order for AE and AB/AW. - Comments are defined to come in lines, which can be wrapped around by the viewer. Since most viewers have a tiny space for comments, this is an empty definition, which no viewer can cope with satisfyingly. Rather comments should come in paragraphs (consisting of words separated by a single blank) separated by empty lines in the file. Paragraphs should be reformatted by the viewer and optionally separated by empty lines in case, the viewer cannot distinguish hard and soft line breaks (as Java). There might be some need for hard (preformatted) paragraphs, admittedly. One could add a special character at paragraph start to distinguish this (E.g. a space or a vertical line |). - The following does not concern the SGF directly. One should fix the preferred way to denote variations. My idea is that any variation should be one to the last move (i.e. another move elswhere) and should be indicated on board (as GoScribe does it by highlighting the alternitive plays). Variation count should start with 1. Of course, there might be need for other types of variations (setting up diagrams for reference e.g.), but the above procedure looks most natural and can coexist, if the viewer raises proper flags to indicate there is an unusual variation. ----------------------- Dr. R. Grothmann grothm@ku-eichstaett.de PGP key available from my hompage http://www.ku-eichstaett.de/MGF/homes/grothmann/grothmann.hml