Macro rustcane::lets

macro_rules! lets {
    (
        let $expect:pat = $result:expr;
        else $failure:expr;
        lift $success:expr;
    ) => { ... };
    (
        $(let $expect:pat = $result:expr;)+
        lift $success:expr;
    ) => { ... };
    (
        $(let $expect:pat = $result:expr;)+
        else $failure:expr;
    ) => { ... };
    (
        $(let $expect:pat = $result:expr;)+
    ) => { ... };
    (
        let $expect_first:pat = $result_first:expr;
        $(let $expect_next:pat = $result_next:expr;)+
        else $failure:expr;
        lift $success:expr;
    ) => { ... };
}

Executes a sequence of pattern matching statements in order. If any match fails, the result is given as an else expression. Otherwise the result is given as the lift expression.