Functress

Functress

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

Functress 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, R, and the following rewriting rules:

K a b           ---> a
S a b c         ---> a c (b c)
R K a b c d     ---> a
R S a b c d     ---> b
R R a b c d     ---> c
R (x y) a b c d ---> d x y

Reductions can be performed only at the beginning on the main expression. For example, R (K K K) does not reduce to R K, but R (K K K) a b c d does reduce to d (K K) K.