Procedural macro for generate [physical_quantity::Unit] in compile time.
``` extern crate typenum;
use unitproc::unit; use constfrac::Frac; use physical_quantity:: { Unit, Dim }; use typenum;
let height = unit!("ft.").pq(5f64) + unit!("in.").pq(8f64); let cm = unit!("cm").value(height).unwrap();
assert_eq!(cm, 172.72); ```
This package is in the very early stage.