Function lambda_calculus::booleans::xor

pub fn xor() -> Term

Applied to a Church-encoded boolean it returns its Church-encoded exclusive disjunction.

XOR := λab.a (NOT b) b = λ λ 2 (NOT 1) 1

Examples

use lambda_calculus::booleans::{xor, tru, fls};
use lambda_calculus::reduction::beta;
use lambda_calculus::reduction::Order::*;

assert_eq!(beta(app!(xor(), tru(), tru()), &Normal, 0), fls());
assert_eq!(beta(app!(xor(), tru(), fls()), &Normal, 0), tru());
assert_eq!(beta(app!(xor(), fls(), tru()), &Normal, 0), tru());
assert_eq!(beta(app!(xor(), fls(), fls()), &Normal, 0), fls());