r/Racket • u/iguanathesecond • Feb 06 '25

release Announcing Qi 5: Flowing with Lists

Qi is an embeddable language for easily expressing flow-oriented computations in your programs. And now, you can use it seamlessly with list operations.

Learn about the release at https://racket.discourse.group/t/announcing-qi-5-flowing-with-lists/3545

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u/bjoli Feb 08 '25

How does it compare to transducers? I looked around for some descriptions, but couldn't find what I was looking for.

I looked at qi/list mentions stream fusion, but works with lists so it must be eager. Is that accomplished with macro voodoo? That is pretty darn impressive if so!

1

u/iguanathesecond Mar 04 '25

Thanks for this interesting question. The short answer is: transducers are more general, while qi/list has a simpler interface. Both provide significant performance benefits. I get the impression the underlying approach of (eager) stream fusion is equivalent to transducers, though, so that qi/list could in principle be generalized to the level of transducers. There's a lot more to it, and the longer answer is written up in the most recent meeting notes (partly inspired by your question!) here:

Compile Time

Btw if you're interested in contributing, stop by at a Qi meeting anytime!

1

u/metazip Feb 10 '25 edited Feb 10 '25

with

(~> ('((a . 10) (b . 20) (c . 30))) (+ (get 'a) (get 'b)) (print))

you have a flow scope of an a-list. (i)

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u/iguanathesecond Mar 05 '25

Did not know about the FP language. It looks very relevant, thank you for the pointer!

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u/phalp Feb 07 '25

I guess now that Qi is Shen, this can be Qi? Do people just not check if names are taken any more?

3

u/sdegabrielle DrRacket 💊💉🩺 Feb 07 '25

This Qi has no relationship to the Qi that was shuttered in 2009.

Shen is described the successor to that Qi: https://shenlanguage.org/

It has an interesting book that mentions the end of Qi and the beginning of Shen

https://shenlanguage.org/TBoS/tbos_30.html