Chess::Piece::Bishop - an object representation of a bishop in a game of chess

Chess documentation Contained in the Chess distribution.

Index

Code Index:

NAME

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Chess::Piece::Bishop - an object representation of a bishop in a game of chess

SYNOPSIS

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    $bishop = Chess::Piece::Bishop->new("f1", "white", 
                                        "White King's bishop");
    $true = $bishop->can_reach("c4");
    $true = $bishop->can_reach("h3");
    $false = $bishop->can_reach("d4");

DESCRIPTION

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The Chess module provides a framework for writing chess programs with Perl. This class forms part of that framework, representing a bishop in a Chess::Game.

METHODS

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Construction

Constructs a new Chess::Piece::Bishop. Requires two scalar parameters containing the initial square and color of the piece. Optionally takes a third parameter containing a description of the piece.

Class methods

There are no class methods for this class.

Object methods

Overrides base class version. Returns a list of squares that this pawn can reach from its current position. See "reachable_squares()" in Chess::Piece for more details on this method.

DIAGNOSTICS

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This module produces no warning messages. See DIAGNOSTICS in Chess::Board or DIAGNOSTICS in Chess::Piece for possible errors or warnings the program may produce.

BUGS

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Please report any bugs to the author.

AUTHOR

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Brian Richardson <bjr@cpan.org>

COPYRIGHT

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Copyright (c) 2002, 2005 Brian Richardson. All rights reserved. This module is Free Software. It may be modified and redistributed under the same terms as Perl itself.

Chess documentation Contained in the Chess distribution. 
package Chess::Piece::Bishop;

use Chess::Board;
use Chess::Piece;
use base 'Chess::Piece';
use strict;

sub new {
    my ($caller, $sq, $color, $desc) = @_;
    my $class = ref($caller) || $caller;
    my $self = $caller->SUPER::new($sq, $color, $desc);
    return bless $self, $class;
}

sub reachable_squares {
    my ($self) = @_;
    my $csq = $self->get_current_square();
    my $hdist = abs(Chess::Board->horz_distance("a1", $csq));
    my $vdist = abs(Chess::Board->vert_distance("a1", $csq));
    my $dist = $hdist > $vdist ? $vdist : $hdist;
    my $sq = Chess::Board->add_horz_distance($csq, -$dist);
    $sq = Chess::Board->add_vert_distance($sq, -$dist);
    my @squares = ( );
    push @squares, Chess::Board->squares_in_line($csq, $sq);
    $hdist = abs(Chess::Board->horz_distance("h1", $csq));
    $vdist = abs(Chess::Board->vert_distance("h1", $csq));
    $dist = $hdist > $vdist ? $vdist : $hdist;
    $sq = Chess::Board->add_horz_distance($csq, $dist);
    $sq = Chess::Board->add_vert_distance($sq, -$dist);
    push @squares, Chess::Board->squares_in_line($csq, $sq);
    $hdist = abs(Chess::Board->horz_distance("a8", $csq));
    $vdist = abs(Chess::Board->vert_distance("a8", $csq));
    $dist = $hdist > $vdist ? $vdist : $hdist;
    $sq = Chess::Board->add_horz_distance($csq, -$dist);
    $sq = Chess::Board->add_vert_distance($sq, $dist);
    push @squares, Chess::Board->squares_in_line($csq, $sq);
    $hdist = abs(Chess::Board->horz_distance("h8", $csq));
    $vdist = abs(Chess::Board->vert_distance("h8", $csq));
    $dist = $hdist > $vdist ? $vdist : $hdist;
    $sq = Chess::Board->add_horz_distance($csq, $dist);
    $sq = Chess::Board->add_vert_distance($sq, $dist);
    push @squares, Chess::Board->squares_in_line($csq, $sq);
    @squares = grep !/^$csq$/, @squares;
    return @squares;
}

1;