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lib/Chess/Plisco/Engine/Position.pm  view on Meta::CPAN

	my $rooks = $self->[CP_POS_ROOKS];
	my $queens = $self->[CP_POS_QUEENS];
	my $kings = $self->[CP_POS_KINGS];

	# We simply assume that a position without pawns is in general a draw.
	# If one side is a minor piece ahead, it is considered a draw, when there
	# are no rooks or queens on the board.  Important exception is KBB vs KN.
	# But in that case the material delta is B + B - N which is greater
	# than B.  On the other hand KBB vs KB is a draw and the material balance
	# in that case is exactly one bishop.
	# These simple formulas do not take into account that there may be more
	# than two knights or bishops for one side on the board but in the
	# exceptional case that this happens, the result would be close enough
	# anyway.
	if (!$pawns) {
		my $delta = (do {	my $mask = $material >> CP_INT_SIZE * CP_CHAR_BIT - 1;	($material + $mask) ^ $mask;});
		if ($delta < CP_PAWN_VALUE
		    || (!$rooks && !$queens
		        && (($delta <= CP_BISHOP_VALUE)
		            || ($delta == 2 * CP_KNIGHT_VALUE)
			        || ($delta == CP_KNIGHT_VALUE + CP_BISHOP_VALUE)))) {

lib/Chess/Plisco/Macro.pod  view on Meta::CPAN

=back

If performance outweighs these problems in your use case, read on!

The source filter is probably not perfect but is able to translate at least
the source code of L<Chess::Plisco>.  If you have trouble like unexpected
syntax errors in your own code, you can use the function C<preprocess()> (see
below), to get a translation of your source file, and find the problem.

Please note that not all translation errors are considered a bug of the
source filter.  If the problem can be avoided by re-formulating your code,
a fix will probably be refused.

=head1 MOTIVATION

Chess programming should be really fast, and in this context the unavoidable
overhead of method or subroutine calls contributes enormously to the execution
time of the software.

In the C programming language, you can use preprocessor macros or inline
functions in order to avoid the calling overhead.  In Perl, this can only