contract XRateProvider {

    //@dev returns current exchange rate (in form of a simple fraction) from other currency to SAN (f.e. ETH:SAN).
    //@dev fraction numbers are restricted to uint16 to prevent overflow in calculations;
    function getRate() public returns (uint32 /*nominator*/, uint32 /*denominator*/);

    //@dev provides a code for another currency, f.e. "ETH" or "USD"
    function getCode() public returns (string);
}
//
function getCode() public returns (string);

//@dev provides a code for another currency, f.e. "ETH" or "USD"