[Atlas22]

Can you elaborate on why using the lookup table makes this objectionable/dishonest? Factorial of 20 is the largest factorial that fits in 64-bit integer. The factorial function you linked is only defined on codon's int type (64-bit signed) so it encompasses the full range of the output datatype.

[regularfry]

It's a targeted micro-optimisation that doesn't say anything about codon's more general-case numeric performance. Unless the other implementations are using the same algorithm it's not comparing like with like.

[tialaramex]

It's not that targeted. Factorial is a reasonable thing to do, optimising for the values that fit in a 64-bit integer is a reasonable thing to do.

If I read this in some code, I wouldn't think "Huh, that's a specialised feature, I bet it's attacking a specific benchmark" I would think, "Oh, that makes sense".

[Atlas22]

Looks like cpython does the same thing if for small n.

https://github.com/python/cpython/blob/a9c6e0618f26270e2591b...