Stefan Israelsson Tampe writes: > (define-syntax-rule (letec f) > (let/ec x (f x)))) > > Actually lead to similar speeds as python3. Please keep in mind that this is math. There are parts of Python that are heavily optimized, for example reading strings from disk. Guile will likely have a hard time to compete with that. But for math Guile is quite a bit faster than Python :-) (next frontier: compete with math that’s implemented via numpy — you can find RPython implementations of the basics of numpy in the pypy-sources: https://foss.heptapod.net/pypy/pypy/-/tree/branch/default/pypy/module/micronumpy ) Best wishes, Arne -- Unpolitisch sein heißt politisch sein ohne es zu merken