Bus 581

Bus 581

Paradigm(s)	Functional
Designed by	User:Hakerh400
Appeared in	2023
Computational class	Turing complete
Major implementations	Uniplemented
File extension(s)	.txt

Bus 581 is an esolang invented by User:Hakerh400 in 2023.

Overview

This programming language is a derivative of the SKI combinator calculus. There are three combinators K, S, T, and the following rewriting rules:

K a b   ---> a
S a b c ---> a c (b c)
T a     ---> b

In the last reduction, for any combinator a, if there exists some combinator b such that a b reduces to K, then T a reduces to one such b (implementation-dependent which one, but it must be done consistently). If there is no such b, then T a reduces to any combinator b (this also must be done consistently).

"Must be done consistently" means that for any fixed a, the expression T a always gives the same result.