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# MIT License, Copyright (c) 2023 Marvin Borner
# De Bruijn numeral system (named by me)
# proof that this numeral system does not support zero/eq/sub/etc. is in
# Wadsworth, Christopher. "Some unusual λ-calculus numeral systems."
# very sad indeed
:import std/Combinator .
# increments De Bruijn numeral
inc [[[2 1]]]
++‣ inc
:test (++(+0d)) ((+1d))
:test (++(+5d)) ((+6d))
# decrements De Bruijn numeral
dec [[1 0 0]]
--‣ dec
:test (--(+1d)) ((+0d))
:test (--(+5d)) ((+4d))
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