Comment by YouAreWRONGtoo | Hacker News Reader

Comment by YouAreWRONGtoo | Hacker News Reader

Delimited continuations as a programming construct were somewhat of interest when I learned about them, but not even my university discussed them.

I don't think I ever had a colleague that even ever heard of the concept, let alone applied it. Of the "smart people", they typically only have heard of plain continuations, if you are lucky.

The debugger in Racket was useful when I used it years ago.

Unfortunately, it's kind of difficult to beat an entire planet cranking out libraries in other languages as many interesting programs are written for an ecosystem; if 90% of your project is building FFIs to make something work, perhaps you can better just choose the language of fools dun jour.

I don't think Scheme is the most academic language, today. Such honor would go to a language supporting a computable version of homotopy types, which I would guess only 1000 people in the world would be capable of using assuming production grade implementations (of which none exist).

> I don't think I ever had a colleague that even ever heard of the concept, let alone applied it. Of the "smart people", they typically only have heard of plain continuations, if you are lucky.

I have a similar picture so far in my work experience. Basically, none of my coworkers ever touched a lispy language. If I said words like "continuation", "environment of a closure", "continuation-passing style" or "macros and metaprogramming", I would get blank stares. Or if I complained about that lambdas in Python are stunted things, they would not understand, because they were only familiar with mainstream OOP and every noun a class paradigm and wouldn't get the ideas where to use lambdas or even inner/nested functions.

This kind of stuff is definitely not part of the usual CS curriculum at universities here (Germany). And of course even more pure fantasy to imagine that to be taught in any boot camps or other higher schools than universities.

Well, maybe some day I will work with people, who have this knowledge, and maaaaybe together we can make something happen employing the ideas and such a language, that implements these concepts well. Or even just work with people, who know FP and have explored building things with it, like I did.

Delimited continuations are quite similar to effect systems that seem to be getting a lot of interest lately. So who knows, maybe they will become more mainstream in the future.

back in the day when we wrote enterprise bullshit in common lisp (!), we had put together a proof of concept where we used delimited continuations to write business processes.

business processes were written in basically full common lisp with very few limitations, and with a few extra primitives to use (and 10x slower due to being interpreted, but that didn't matter at all). when a process reached a point where it was waiting for some external event (e.g. displaying a GUI for a user and waiting for their feedback, or sleeping until a deadline), then it got serialized into the (SQL) database.

it was pretty cool! when a user logged in, there was a list of processes waiting for him that he could click to see and interact with. all this with the transactional guarantees of the sql backend because the business objects were also stored in the same database.

https://github.com/hu-dwim/hu.dwim.delico was the continuation lib, hu.dwim.perec was the object relational mapper, and hu.dwim.serializer was used to turn CL objects into SQL blobs (with some properties extracted as reified SQL schema elements to be able to search for the suspended processes).

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