.gitattributes

*.sol linguist-language=Solidity

payment-game.sol

import "fmg-core/contracts/State.sol";

contract PaymentGame {
    using State for bytes;
    // The core State library contains all attributes needed for a payment game state!
    
    function validTransition(bytes _old, bytes _new) public pure returns (bool) {
        uint[] oldResolution = State.resolution(_old);
        uint[] newResolution = State.resolution(_new);
        
        // conserve total balance
        require(oldResolution[0] + oldResolution[1] == newResolution[0] + newResolution[1])
        
        // can't take someone else's funds by moving
        uint8 i = _new.indexOfMover();
        require(newResolution[i] <= oldResolution[i]);
        
        return true;
    }
}