NAME

Games::Checkers - Play the Checkers games

SYNOPSIS

# automatical computer-vus-computer play script
use Games::Checkers::Constants;
use Games::Checkers::Board;
use Games::Checkers::BoardTree;

my $board = new Games::Checkers::Board;
my $color = White;
my $numMoves = 0;
print $board->dump;

while ($board->canColorMove($color)) {
    sleep(2);
    # allow 100 moves for each player
    die "Automatical draw\n" if $numMoves++ == 200;
    my $boardTree = new Games::Checkers::BoardTree
        ($board, $color, 2);  # think 2 steps ahead
    my $move = $boardTree->chooseBestMove;  # or: chooseRandomMove

    $board->transform($move);
    print $move->dump, "\n", $board->dump;
    $color = ($color == White)? Black: White;
}

print "\n", ($color == White? "Black": "White"), " won.\n";

ABSTRACT

Games::Checkers is a set of Perl classes implementing the Checkers game play. Several national rule variants are supported. A basic AI heuristics is implemented using the Minimax algorithm. Replay of previously recorded games is supported too.

DESCRIPTION

This package is intended to provide complete infrastructure for interactive and automatic playing and manipulating of Checkers games. Some features are not implemented yet.

Currently supported board sizes:

* 8x8
* 10x10 (not yet, but will be soon hopefully)

Currently supported variants:

* Russian Checkers (AI and game replay)
* British Checkers (game replay)
* Italian Checkers (game replay, set $ENV{ITALIAN_BOARD_NOTATION})

Currently supported game file formats:

* .pdn files (trying to detect a lot of broken notations too)
* .pdn.gz files (automatically uncompressed on the fly)

Currently installed scripts:

* pcheckers-auto-play
* pcheckers-replay-games

In the future one script pcheckers may be installed that will include:

* automatical AI game play (current script pcheckers-auto-play)
* recorded game replay (current script pcheckers-replay-games)
* interactive game play of 1 or 2 human players

GUI interface may be added too (gtk-pcheckers), or may be not.

The Rules of Checkers

Board

The regular checkerboard is comprised of 64 squares of contrasting colors, like black and white. The checker pieces may be red and white in color (or any combination of contrasting colors), usually grooved.

The black board squares are numbered either 1 to 32 or using the chess a1 to h8 notation. The diagram below shows the pieces set up for play, with Black occupying squares 1 to 12 (lines 6 to 8 in the chess notation) and White occupying squares 21 to 32 (lines 1 to 3 in the chess notation).

Chess notation:

  +-------------------------------+
8 |   |:@:|   |:@:|   |:@:|   |:@:|
  |---+---+---+---+---+---+---+---|
7 |:@:|   |:@:|   |:@:|   |:@:|   |
  |---+---+---+---+---+---+---+---|
6 |   |:@:|   |:@:|   |:@:|   |:@:|
  |---+---+---+---+---+---+---+---|
5 |:::|   |:::|   |:::|   |:::|   |
  |---+---+---+---+---+---+---+---|
4 |   |:::|   |:::|   |:::|   |:::|
  |---+---+---+---+---+---+---+---|
3 |:O:|   |:O:|   |:O:|   |:O:|   |
  |---+---+---+---+---+---+---+---|
2 |   |:O:|   |:O:|   |:O:|   |:O:|
  |---+---+---+---+---+---+---+---|
1 |:O:|   |:O:|   |:O:|   |:O:|   |
  +-------------------------------+
    a   b   c   d   e   f   g   h  

Numerical notation:

        1       2       3       4
  +-------------------------------+
  |   |:@:|   |:@:|   |:@:|   |:@:| 4
  |---+---+---+---+---+---+---+---|
 5|:@:|   |:@:|   |:@:|   |:@:|   |
  |---+---+---+---+---+---+---+---|
  |   |:@:|   |:@:|   |:@:|   |:@:|12
  |---+---+---+---+---+---+---+---|
13|:::|   |:::|   |:::|   |:::|   |
  |---+---+---+---+---+---+---+---|
  |   |:::|   |:::|   |:O:|   |:::|20
  |---+---+---+---+---+---+---+---|
21|:O:|   |:O:|   |:::|   |:O:|   |
  |---+---+---+---+---+---+---+---|
  |   |:O:|   |:O:|   |:O:|   |:O:|28
  |---+---+---+---+---+---+---+---|
29|:O:|   |:O:|   |:O:|   |:O:|   |
  +-------------------------------+
    29      30      31      32

Each player (White and Black) controls its own army of pieces. Pieces move only on dark squares which are numbered. The white pieces always move first in opening the game. For example, suppose White were to open the game by moving the piece on 23 to the square marked 19, like shown above. This would be recorded as 23-19. Or e3-f4 in the chess notation. Another possible notation is ef4.

The goal

The goal in the checkers game is either to capture all of the opponent's pieces or to blockade them. If neither player can accomplish the above, the game is a draw.

Moves

Starting with White, the players take turns moving one of their own pieces. A 'piece' means either a 'man' (other name is 'pawn') - an ordinary single checker or a 'king' which is what a man becomes if it reaches the last rank (see kings). A man may move one square diagonally only forward - that is, toward the opponent - onto an empty square.

Captures

Checkers rules state that captures or 'jumps' are mandatory. If a square diagonally in front of a man is occupied by an opponent's piece, and if the square beyond that piece in the same direction is empty, the man may 'jump' over the opponent's piece and land on the empty square. The opponent's piece is captured and removed from the board.

In some variants, if in the course of single or multiple jumps the man reaches the last rank, becoming a king, the turn shifts to the opponent; no further 'continuation' jump is possible.

The kings

When a single piece reaches the last rank of the board by reason of a move, or as the completion of a 'jump', it becomes a king; and that completes the move, or 'jump'.

A king can move in any of the four diagonal directions and skip zero, one or more empty cells, as the limits of the board permit. Similarly, the king can optionally capture exactly one opponent piece at a time during such jump.

In some variants, a king has the same limits as a man (can't skip empty cells), just moves and captures in 4 diagonal directions, as opposed to 2 forward directions.

CLASSES

Games::Checkers
Games::Checkers::Board
Games::Checkers::BoardConstants
Games::Checkers::BoardTree
Games::Checkers::BoardTreeNode
Games::Checkers::CompPlayer
Games::Checkers::Constants
Games::Checkers::CountMoveList
Games::Checkers::CreateMoveList
Games::Checkers::CreateUniqueMove
Games::Checkers::CreateVergeMove
Games::Checkers::DeclareConstant
Games::Checkers::ExpandMoveList
Games::Checkers::FigureIterator
Games::Checkers::IteratorConstants
Games::Checkers::Iterators
Games::Checkers::KingBeatIterator
Games::Checkers::KingStepIterator
Games::Checkers::LocationConversions
Games::Checkers::LocationIterator
Games::Checkers::Move
Games::Checkers::MoveConstants
Games::Checkers::MoveListNode
Games::Checkers::MoveLocationConstructor
Games::Checkers::PDNParser
Games::Checkers::PawnBeatIterator
Games::Checkers::PawnStepIterator
Games::Checkers::PieceRuleIterator
Games::Checkers::Player
Games::Checkers::PlayerConstants
Games::Checkers::UserPlayer
Games::Checkers::ValidKingBeatIterator

SEE ALSO

http://migo.sixbit.org/software/pcheckers/

AUTHOR

Mikhael Goikhman <migo@homamail.com>

cpanm Games::Checkers

perl -MCPAN -e shell
install Games::Checkers