Crate flowcontrol 

Macros

exenum

Convert an enum to an option:

shed

A break shed. This defines a stopping point for break in the enclosed code, as if you had wrapped it in loop {}.

superif

Execute the second block where the first block breaks with the label, like the first block is a giant if condition.

ta_return

Type-assert return type: explicitly communicate the Ok return type for the block to the compiler via unreachable code.