Function add 

pub fn add() -> Term

Applied to two Stump-Fu-encoded numbers it produces their sum.

ADD ≡ λnm.n (λcp.c SUCC m) m ≡ λ λ 2 (λ λ 2 SUCC 3) 1

Example

use lambda_calculus::data::num::stumpfu::add;
use lambda_calculus::*;

assert_eq!(beta(app!(add(), 1.into_stumpfu(), 2.into_stumpfu()), NOR, 0), 3.into_stumpfu());
assert_eq!(beta(app!(add(), 2.into_stumpfu(), 3.into_stumpfu()), NOR, 0), 5.into_stumpfu());