[ncmncm]

This is brilliant! Equivalent, in its way, to C++ template metaprogramming. It was cheeky to do a Forth instead of an ML. The traditional way to demonstrate TC is by sieving primes at compile time.

C++ is actively replacing its compile-time ML with core language features, but isn't there yet. Still, it has been many years since I needed to code any of my own TMP.

[bonzini]

Sort of, arithmetic is implemented (through the trait-eval crate) from the Peano axioms. Probably it is not very fast, even in comparison to C++ standards.

[Ashymad]

Indeed, could possibly be sped up by using typenum[1] instead of trait-eval, as it is not Peano axioms based.

[1] https://docs.rs/typenum/