// SPDX-License-Identifier: GPL-3.0-or-later
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

pragma solidity ^0.8.0;

/**
 * @title Denominations
 * @dev Provides a list of ground denominations for those tokens that cannot be represented by an ERC20.
 * For now, the only needed is the native token that could be ETH, MATIC, or other depending on the layer being operated.
 */
library Denominations {
    address internal constant NATIVE_TOKEN = 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE;

    // Fiat currencies follow https://en.wikipedia.org/wiki/ISO_4217
    address internal constant USD = address(840);

    function isNativeToken(address token) internal pure returns (bool) {
        return token == NATIVE_TOKEN;
    }
}