Function lambda_calculus::data::list::church::is_nil

source · 
pub fn is_nil() -> Term
Expand description

Applied to a Church-encoded list it determines if it is empty.

IS_NIL ≡ λl.l TRUE (λax.FALSE) ≡ λ 1 TRUE (λ λ FALSE)

§Example

use lambda_calculus::data::list::church::{is_nil, nil};
use lambda_calculus::*;

assert_eq!(beta(app(is_nil(), nil()), NOR, 0), true.into());