Re: Screaming-Fist: a JIT framework for Guile

[Maxime Devos]

Op 03-12-2023 om 18:26 schreef Nala Ginrut:
> (jit-define (square x)
>    (:anno: (int) -> int)
>    (* x x))
> (square 5)


Potentially-overflowing arithmetic involving ints (not unsigned ints, 
but ints)? Best document somewhere to what the jit code '(* x x)' 
evaluates when (not (<= min-int (* x x) max-int))).

Personally, I'm in favor of explicit long names like

*/error-on-overflow     (<-- maybe on the C-level the function could 
return a tagged union representing (failure [no value]) / (success [some 
value], at a slight performance cost)
*/wrap-around
*/undefined-on-overflow (<-- like in C, for maximal performance and 
dragons).

(Likewise for +, - and unsigned int)

Sure, they are a bit verbose, but they are explicit and 
non-explicitness+undefined behaviour of'*' in C has caused serious 
issues in the past, so I'd think it's better that the programmer has to 
choose what, in their situation, are the appropriate semantics.

If/when someone desired shorter names, there could be a
(jit-define-alias * */wrap-around) or something like that for that?

Best regards,
Maxime Devos

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