# MIT License, Copyright (c) 2023 Marvin Borner

:import std/Combinator .
:import std/Logic .

zero [[1]] ⧗ Scott

inc [[[0 2]]] ⧗ Scott → Scott

:test (inc zero) ([[0 zero]])
:test (inc (inc zero)) ([[0 [[0 zero]]]])
:test (inc (inc (inc zero))) ([[0 [[0 [[0 zero]]]]]])

dec [0 zero [0]] ⧗ Scott → Scott

:test (dec zero) (zero)
:test (dec (inc zero)) (zero)
:test (dec (inc (inc zero))) (inc zero)

zero? [0 true [false]] ⧗ Scott → Boolean

:test (zero? zero) (true)
:test (zero? (inc zero)) (false)
:test (zero? (inc (inc zero))) (false)

add z [[[1 0 [inc (3 0 1)]]]] ⧗ Scott → Scott → Scott

:test (add zero zero) (zero)
:test (add zero (inc zero)) (inc zero)
:test (add (inc zero) zero) (inc zero)
:test (add (inc zero) (inc zero)) (inc (inc zero))