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<H1><TT>Games::Chess::Referee</TT> Perl Module</H1>
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<TT>Games::Chess::Referee</TT><BR>
Version 0.003<BR>
Gregor N. Purdy<BR>
<A HREF="mailto:gregor@focusresearch.com">mailto:gregor@focusresearch.com </A><BR>
<A HREF="http://www.focusresearch.com/gregor/">http://www.focusresearch.com/gregor/index</A><BR>
2006-03-26<BR>
<P>
Copyright © 1999-2006 Gregor N. Purdy. All rights reserved.
This program is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.<P>
This is an early conversion of my first chess-related Perl
program, <TT>chess.pl</TT>, which provided just enough functionality to
permit tracking the movements of pieces throughout a game. One
notable feature is the ability to provide incomplete ply notation,
allowing the program to figure out, for example, the type of the
piece being moved, or whether the ply represents a capture (<TT>x</TT>) or
occupation (<TT>-</TT>). This functionality will be broadened in the future
to permit partial space specification (e.g. `<TT>cxd4</TT>'), and other
cases of standard chess move notation.<P>
<H3>PREREQUISITES</H3>
This module uses a patched version of the module <TT>Games::Chess</TT>,
version 0.002. The patches are included in the <TT>gc-0.002.diff file</TT>.
The diffs were created by the command:<P>
<BLOCKQUOTE>
<TT>diff -Naur Games-Chess-0.002 Games-Chess-0.002.patch</TT>
</BLOCKQUOTE>
They are intended to be used with the <TT>patch</TT> program (see below).<P>
The patches are to <TT>Chess.pm</TT> and <TT>Chess.pod</TT>, and fix a small bug and
address some discrepancies between the documentation and the code:<P>
<OL>
<LI>
Changed `<TT>Games::Piece->new</TT>' to `<TT>Games::Chess::Piece->new</TT>' in one place.
</LI>
<LI>
<TT>can_castle()</TT> is changed to accept a color and a piece, per the
documentation. Its previous implementation accepted a single
character code from the set {'K', 'Q', 'k', 'q'} instead.
</LI>
<LI>
A corresponding change later in the code to use <TT>can_castle()</TT> in
this modified way.
</LI>
<LI>
Changed the POD documentation to use the name <TT>halfmove_clock()</TT>
instead of <TT>halfmove()</TT> for the accessor function for the halfmove
clock.
</LI>
</OL>
<H3>INSTALLING</H3>
<OL>
<LI>
Download <TT>Games::Chess</TT> and this package from your favorite CPAN
mirror to your favorite staging area (<TT>$STAGE</TT> below):
<BLOCKQUOTE><TT>
cd $STAGE<BR>
ftp ...<BR>
bin<BR>
cd ...<BR>
get Games-Chess-0.002.tar.gz<BR>
cd ...<BR>
get Games-Chess-Referee-0.002.tar.gz<BR>
bye<BR>
</TT></BLOCKQUOTE>
</LI>
<LI>
Unpack your distributions:
<BLOCKQUOTE><TT>
tar xvzf Games-Chess-0.002.tar.gz<BR>
tar xvzf Games-Chess-Referee-0.002.tar.gz<BR>
</TT></BLOCKQUOTE>
</LI>
<LI>
Apply the patches to Games::Chess:
<BLOCKQUOTE><TT>
cp -a Games-Chess-0.002 Games-Chess-0.002.patch<BR>
cd Games-Chess-0.002.patch<BR>
patch -p1 < $STAGE/Games-Chess-Referee-0.002/gc-0.002.diff<BR>
</TT></BLOCKQUOTE>
</LI>
<LI>
Make, test and install <TT>Games::Chess</TT>:
<BLOCKQUOTE><TT>
cd $STAGE/Games-Chess-0.002.patch<BR>
perl Makefile.PL<BR>
make<BR>
make test<BR>
make install<BR>
</TT></BLOCKQUOTE>
</LI>
<LI>
Make, test and install <TT>Games::Chess::Referee</TT>:
<BLOCKQUOTE><TT>
cd $STAGE/Games-Chess-Referee-0.002<BR>
perl Makefile.PL<BR>
make<BR>
make test<BR>
make install<BR>
</TT></BLOCKQUOTE>
</LI>
<LI>
Take a look at tryme and the documentation and write some scripts
that use the code.
</LI>
<LI>
Send your comments and suggestions to the author of this module
and the author of <TT>Games::Chess</TT>, as appropriate.
</LI>
</OL>
<H3>FUTURE DIRECTIONS</H3>
Eventually, there will be a <TT>Games::Chess::Move</TT> module/class,
that will interact with the <TT>Position</TT> and <TT>Piece</TT> classes to provide an
integrated environment for working with chess games. The <TT>Referee</TT>
module will be converted into a class.<P>
Very abbreviated notation (such as <TT>xb4</TT>, <TT>c5</TT>, <TT>dxe7</TT>,
<TT>QxR</TT>, etc. would be great, with ambiguity detection).<P>
Also, much more work needs to be done to create a fully functional
referee. Subsequent to that, however, Perl-built chess bots could
be possible, and the referee could be enhanced to the point that
it could be used for on-line chess matches.<P>
Interesting future work would be to wrap the GNU chess engine in
a Perl blanket. This would be most interesting if it was done
in such a way that we weren't just putting a layer over the
terminal interface, but rather, turning the core of the C code
into a Perl-wrapped engine that interfaces with the board via
the Referee.<P>
<H3>CHANGES FROM VERSION 0.001</H3>
Modified to use <TT>Games::Chess</TT> by Gareth Rees for the underlying
board management and operations. Uses a privately modified version
of Gareth's <TT>Games::Chess</TT> code, version 0.002. Patches have been
submitted to Gareth.<P>
Included a small script, <TT>tryme</TT>, that has the same test game in it
as the test <TT>t/referee.t</TT>. Run the <TT>tryme</TT> script thusly (if running
before installing the package):<P>
<BLOCKQUOTE><TT>
perl -Iblib/lib tryme
</TT></BLOCKQUOTE>
so you can see its output.<P>
Removed the <TT>exit()</TT> statement that prevented the <TT>t/referee.t</TT> test from
doing anything very interesting [:-)].<P>
<H2>Download</H2>
<UL>
<LI><A HREF="Games-Chess-Referee-0.001.tar.gz">Version 0.001</A> (Released 1999-04-19)</LI>
<LI><A HREF="Games-Chess-Referee-0.002.tar.gz">Version 0.002</A> (Released 1999-04-26)</LI>
</UL
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<FONT SIZE=-1>Copyright © 1999-2006 Gregor N. Purdy</FONT>
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