Macro compactmap::declare_compactmap_token

macro_rules! declare_compactmap_token {
    ($x:ident) => { ... };
}

Create usize-equivalent struct that implements From<usize> and Into<usize>

For the wrapper.

#[macro_use] extern crate compactmap;
use compactmap::wrapped::CompactMap;
declare_compactmap_token!(MyCompactmapIndex);