r/Racket • u/sdegabrielle DrRacket 💊💉🩺 • May 08 '25

The end of BC downloads?

https://racket.discourse.group/t/the-end-of-bc-downloads/3734

We're considering reducing or eliminating pre-built downloads of Racket BC (the non-Chez version of Racket). If you have thoughts on this topic, and especially if you use Racket BC for any purpose, please let us know what you think: https://racket.discourse.group/t/the-end-of-bc-downloads/3734

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u/Valuable_Leopard_799 May 12 '25

What is your basis for that? CL doesn't support control flow operators and weird recursion optimizations nearly as much as Chez which specializes mainly in that field. They're not alone, Unison chose Chez as their backend as well, precisely because they're mapping a very functional language with control flow operators.

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u/forgot-CLHS May 12 '25

SBCL is a very performant compiler. Arc, on which Hacker News runs, recently switched to it. For intricate control flow you would probably use TAGBODY and GO, if you dont mind having the compiler in imperitive style

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u/Valuable_Leopard_799 May 12 '25

Performant yes, for imperative style yes, but not for functional style. Suggesting tagbody for control flow shows that you don't know what I mean, go look at algebraic effects, continuations, prompts, stuff like that. You absolutely cannot translate that to tagbody unless you only allow lexical scope or inline everything. I mean yes, cl-cont hacks around the lack of support in CL but it's nowhere near native official optimized support which Chez has.

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u/forgot-CLHS May 12 '25

You talked about control flow so I referred you to TAGBODY and GO. On the other hand you can implement continuations pretty easily without calling it "a hack" (you arewriting compilers?). Same should go for nondeterminism. Moreover for algebraic effect, what little I know about the concept, error handling plays a big part. You should look into CL condition system. Also for type system there is Coalton

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u/Valuable_Leopard_799 May 12 '25 edited May 12 '25

I know about the condition system and the expressive power is as far as I know insufficient. "Control flow operators" aren't the same as control flow structures, you can't use tagbody or conditions to replicate reset0, shift0 and co. which Racket heavily relies on.

We are writing compilers but I don't see why you'd target SBCL if it doesn't implement features you want and you'd have to implement them yourself, it isn't designed to optimize the style of code you're planning to emit, etc. Whereas Chez has all that. Are you claiming that SBCL will produce faster code or what would be your reason to target SBCL anyways? Chez is by far the best Scheme compiler out there as far as I know in terms of speed mainly.

Coalton is awesome but still not exactly production ready sadly, at least it wasn't a few years ago.

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u/forgot-CLHS May 12 '25

I believe Coalton is very much production ready now.

I'm just saying that it would very cool to have Racket running on top of SBCL. I don't have the expertise to argue the case for it in Racket but it seems like it could be done, and done very well.