Standard library: Relative timelocks

[schoen]

Project

library

Describe the feature

We should have relative timelock functions in the standard library to replace the deprecated timelock jets. These are my current versions from https://docs.simplicity-lang.org/documentation/timelocks.

fn enforce_relative_distance(min_distance: Distance) {
    // Assert that the current input is spent in a transaction that can
    // only appear a distance of at least min_distance blocks after the input's
    // UTXO. Panic otherwise.

    // Transaction version must be at least 2.
    assert!(jet::le_32(2, jet::version()));

    // Fetch and parse sequence for current transaction
    let parsed_seq: Option<Either<Distance, Duration>> = jet::parse_sequence(jet::current_sequence());

    match parsed_seq {
        // Failure condition
        None => assert!(false),
        // This is either a distance or a duration, but only a distance is
        // acceptable here.
        Some(actual_data: Either<Distance, Duration>) => match actual_data {
            // Is the actual distance greater than or equal to the specified min_distance?
            Left(actual_distance: Distance) => assert!(jet::le_16(min_distance, actual_distance)),
            // A duration is not acceptable in this context.
            Right(actual_duration: Duration) => assert!(false),
        },
    }
}

fn enforce_relative_duration(min_duration: Duration) {
    // Assert that the current input is spent in a transaction that can only
    // appear a duration of at least min_duration units of 512 seconds after
    // the input's UTXO. Panic otherwise.

    // Transaction version must be at least 2.
    assert!(jet::le_32(2, jet::version()));

    // Fetch and parse sequence for current transaction
    let parsed_seq: Option<Either<Distance, Duration>> = jet::parse_sequence(jet::current_sequence());

    match parsed_seq {
        // Failure condition
        None => assert!(false),
        // This is either a distance or a duration, but only a duration is
        // acceptable here.
        Some(actual_data: Either<Distance, Duration>) => match actual_data {
            // A distance is not acceptable in this context.
            Left(actual_distance: Distance) => assert!(false),
            // Is the actual duration greater than or equal to the specified min_duration?
            Right(actual_duration: Duration) => assert!(jet::le_16(min_duration, actual_duration)),
        },
    }
}