NAME

Chess::Rep::Coverage - Expose chess ply potential energy

VERSION

version 0.1101

SYNOPSIS

  use Chess::Rep::Coverage;

  my $g = Chess::Rep::Coverage->new();
  print $g->board();

  $g->set_from_fen('8/8/8/3pr3/4P3/8/8/8 w ---- - 0 1');
  $c = $g->coverage(); # Recalculate board status
  print $g->board();
  $piece = $g->piece_at($row, $col);
  $boolean = $g->protected($row, $col);
  $boolean = $g->threatened($row, $col);
  $boolean = $g->white_can_move($row, $col);
  $boolean = $g->black_can_move($row, $col);

DESCRIPTION

This module exposes the "potential energy" of a chess ply by returning a hash reference of the board positions, pieces and their "attack or protection status."

METHODS

new()

Return a new Chess::Coverage object.

coverage()

  $c = $gcoverage();

Set the cover attribute and return a data structure, keyed on board position, showing

  occupant            => Human readable piece name
  color               => Color number of the occupant
  index               => The C<Chess::Rep/Position> board position index
  move                => List of positions that are legal moves by this piece
  protects            => List of positions that are protected by this piece
  threatens           => List of positions that are threatened by this piece
  is_protected_by     => List of positions that protect this piece
  is_threatened_by    => List of positions that threaten this piece
  white_can_move_here => List of white piece positions that can move to this position
  black_can_move_here => List of black piece positions that can move to this position

board()

  print $self->board();

Return an ASCII board layout with threats, protections and move statuses.

Protection and threat is indicated by p/t. White and black movement is indicated by w:b.

For example, the FEN 8/8/8/3pr3/4P3/8/8/8 w ---- - 0 1 is rendered as:

       A     B     C     D     E     F     G     H
    +-----+-----+-----+-----+-----+-----+-----+-----+
  1 |     |     |     |     |     |     |     |     |
    +-----+-----+-----+-----+-----+-----+-----+-----+
  2 |     |     |     |     |     |     |     |     |
    +-----+-----+-----+-----+-----+-----+-----+-----+
  3 |     |     |     |     |     |     |     |     |
    +-----+-----+-----+-----+-----+-----+-----+-----+
  4 |     |     |     | 0:1 | 0/2 |     |     |     |
    +-----+-----+-----+-----+-----+-----+-----+-----+
  5 |     |     |     | 1/1 | 0/0 | 0:1 | 0:1 | 0:1 |
    +-----+-----+-----+-----+-----+-----+-----+-----+
  6 |     |     |     |     | 0:1 |     |     |     |
    +-----+-----+-----+-----+-----+-----+-----+-----+
  7 |     |     |     |     | 0:1 |     |     |     |
    +-----+-----+-----+-----+-----+-----+-----+-----+
  8 |     |     |     |     | 0:1 |     |     |     |
    +-----+-----+-----+-----+-----+-----+-----+-----+

This means that, 1) the black pawn at D5 can move to D4 and can capture the white pawn at E4; 2) the white pawn at E4 can capture the pawn at D5 but cannot move; 3) the black rook at E5 protects the black pawn at D5, can capture the white pawn at E4 and can move to F5 through H5 or E6 through E8.

move_probability()

  @piece_moves = move_probability(%arguments);

Compute the "likelihood" of moving to a protected or threatened position.

SEE ALSO

* The code in this distribution examples/ and t/ directories.

* Chess::Rep

* http://en.wikipedia.org/wiki/Forsyth-Edwards_Notation

AUTHOR

Gene Boggs <gene@cpan.org>

COPYRIGHT AND LICENSE

This software is copyright (c) 2014 by Gene Boggs.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.

cpanm Chess::Rep::Coverage

perl -MCPAN -e shell
install Chess::Rep::Coverage