NAME
Game::Backgammon - backgammon as a reusable engine
SYNOPSIS
use Game::Backgammon;
my $game = Game::Backgammon->new(seed => $bytes);
$game->turn; # who the opening roll sent first
$game->dice; # [5, 2], from the seed
for my $turn (@{ $game->legal_turns }) { print $turn->notation, "\n" }
$game->play('8/3 6/4') or die $@;
$game->status; # 'active' or 'finished'
$game->result->margin; # 'single', 'gammon', 'backgammon'DESCRIPTION
Pure rules: no input, no output, no clock, and no randomness beyond the seed. A game is its seed plus the turn chosen at each roll, and "replay" rebuilds it from exactly that.
It is the engine behind the backgammon at https://peer2peergames.com.
A turn is the unit
Two dice mean up to two checkers move and doubles mean four, and the rules binding which combinations are legal are properties of the whole set. So legal_turns offers whole turns and play takes one. See Game::Backgammon::Rules.
The dice are checkable but not predictable
Roll n is SHA-256($seed . "roll:$n:..."), so a finished game can be replayed and verified from its seed, while somebody who learns the seed mid-game learns nothing about what is coming. See Game::Backgammon::Dice.
No doubling cube, and no draws
There is no cube: it is not a wager, but it reads like one, and leaving it out costs the game little. Backgammon cannot be drawn, so a result always has a winner.
METHODS
new(seed => $bytes)
The opening roll decides who starts and gives them their dice.
dice, legal_turns, play($turn_or_notation)
status, result, turn, board, history, to_log
seed
The 32 bytes every roll is derived from.
rolls
How many rolls the game has consumed: the dice index replay needs.
pending
The dice rolled and not yet played.
other
The other player's name.
finish(winner => ..., reason => ...)
A finish imposed from outside: a resignation, a timeout, an abandoned game. A resignation concedes a single.
replay(seed => ..., turns => [ '8/5 6/5', ... ])
SEE ALSO
Game::Backgammon::Board, Game::Backgammon::Rules, Game::Backgammon::Dice, Game::Backgammon::Result.
AUTHOR
LNATION, <email@lnation.org>
LICENSE AND COPYRIGHT
This software is Copyright (c) 2026 by LNATION.
This is free software, licensed under the Artistic License 2.0.