Loving flaws like buffer overflows looks more like a Stockholm syndrome to me: when the reality is terrible, people learn to find lovable bits in it, just to avoid insanity. C has its place, but its place is very, very close to hardware. (And I hope Zig will push it from there, too, eventually.)

I don't think that better static guarantees are going to come from direct adoption of languages like Haskell, or some tools like Coq or Agda. They will continue coming the same way Rust and Typescript gone mainstream: by integrating them into practical (not research) languages, and allowing escape hatches, prominently marked. Advanced features need adaptation to be ergonomic, after that they feel natural. This happens to every scientific achievement that has a large practical value: compare a laser on an optical workbench in a lab to a laser in a DVD drive, or a laser pointer.

I would likely laugh if someone told me in 1995 that pure FP approaches will conquer GUI development. Nevertheless, this happened twice: first with XSLT in 2000s, then with React in 2010s.

And I don't think it would even be improved by being pure; Elm has much more boilerplate to do similar things.

It's easy to test right? Can you replace calls/expressions with their result-value? If no, it's not pure-functional.

You can certainly replace most hooks with static return values. Many hooks are heavily memoizable and in turn heavily memoized which is how they find their performance in practice.

Multi-hook interactions generally follow a lot of the laws of monadic binding and a lot of the "hooks rules" aren't that strange in terms of monads: monadic binds have sequencing that matters (and dependencies you might track). The order of hooks matter in the same way that the order of IO binds or the order of Futures/Promises awaits.

Again, it is certainly hard to call it "pure" functional in most ways, it has a lot of impurity, but it is certainly "deeply" functional. There's not really a better paradigm to call what is React is doing with Hooks than "functional programming". The language of monads is somewhat helpful in reasoning about how Hooks work and where they sit in the paradigm. They definitely make everything a bit more "impure", especially from the strict mathematical sense of "pure functions are entirely dependent on their parameters". Especially with Hooks not being represented parametrically (which I did mention I think can be something of a problem and I wish wasn't the case).

"most" is not good enough. The idea of PFP is precisely that there is no exception, otherwise all guarantees are void. If I cannot rely on an expression to be referential transparent, then it means I have to look into to find out - and with that, the advantage of PFP goes through the window.

> The order of hooks matter in the same way that the order of IO binds or the order of Futures/Promises awaits.

The difference is that if you create an effect in a PFP style (like in Haskell), the effect itself doesn't do anything. You can now combine that effect with another effect in some way, e.g. by sequencing, which means first effect A and then afterwards effect B is executed. Yes. But what you get back is, again, an effect that doesn't do anything. So what you need to do is to build a datastructure of effects.

Do you do that with hooks? I don't think so. With hooks, you call one, then call another, and yeah, the result depends on the order just like with an effect monad like IO. But the difference is that once the line of code that calls the hook is executed, something happens and the world has changed. This is not true when you can the line of code that builds the datastructure for the effect execution.

You would have handle hooks like promises for this to work in a PFP way. But maybe I misunderstand and you can clarify it with a code example?

Otherwise, I just think it's about terminology. I agree that there is a relation between the two things, but we shouldn't give it the same name, because it is still not the same concept.

The data structures that Hooks build in React gets built in a strangely bound, somewhat liminal `this` space so it effectively "disappears" in JS. That's certainly not how I would have built it. You are right that I probably would have used something more like JS Promises, given the choice. But I didn't build React's Hook systems, I'm just an outside critic. I'm very happy to agree that use of `this` bound things is about as impure functionally as you get in JS. (That said, it is a very JS solution that predates React and gets to old debates of whether or not JS is truly "OO". Prototypical OO is a gray space between OO and functional paradigms.)

Hooks are never imperative, even in the most complex multi-hook components. They use and build data structures. Those data structures are mostly hidden from view and hard to inspect, but they exist.

But you don't. It is react that builds the datastructure in the background, not you that builds and controls it. Hooks might be declarative, but this is actually orthogonal to being pfp or not.

All of that is totally fine btw., there is no need for everything to follow a pfp style. It's a tradeoff. But we shouldn't call something pfp that isn't, even if it is closely related.

It's very different from jQuery and the callback hell, or from any two-way bindings all the way to Visual Basic.

It teaches you to value immutability and purity, to crave it (then comes Ramda, etc).

Also, Promises are not entirely monadic, and `async` is not entirely the do-notation, but you can use a lot of monadic approaches, and reap some of the benefits.

Exactly, and that's why it is not pf. It's really as simple as that.

It's also not as if it would be theoretical distinction that has no meaning for praxis. It does. For instance, since I cannot control the execution of React's cycle (including rendering) it becomes hard(er) to do certain kind of page animations that should happen between renders.

> It's very different from jQuery and the callback hell

Yes, it is nicer to use. But it is not pfp-style.

Spoken Japanese you can't break the rules because everyone else instantly becomes unable to understand you. They barely use local accents/dialects in media because of this.

Only if you are the developer (victim ) it is fun to work with buffer overflows if you are the security researcher (law enforcement) or a hacker (kidnapper )

Last year I did advent of code in Lean4. I had written a heap implementation that I didn't end up using. As an exercise, I went back and added proofs for my indicies and a termination proof. I got the termination proof down to `0 < 0` and realized that I had an off by one error (I'd used the math for a 1-based array with a 0-based array).

My take-away was that this stuff can catch real bugs, but also that people are not going to do this stuff day-to-day. Maybe some equality saturation thing will make it possible for the compiler to sort out the proof in most cases. If the compiler can hit 80%, you could use it as a linter. (If you want something stricter, you can do totality checking but have escape hatches like Idris' assert_total / assert_smaller.)

> Even though at the time I wanted xhtml to win the battle of structured formats for the web, in hindsight I now believe messy html 5 was the way to go.

The structured vs unstructured thing is also interesting. I came to a similar conclusion years ago. I'd written some heuristics to pull recipes out of web pages, and also use embedded microdata on some pages. I found I got better results with my heuristics because of bad encoding of the structured data. E.g. a web site was missing entire ingredient blocks in their encoding because their process / data model didn't accommodate recipes with multiple ingredient blocks.

You seem to be implying Esperanto's lack of popularity is related to its regularity, but I don't think it has anything to do with that - it comes down to network effects. It's not an official language in any country. There are very, very few native speakers of Esperanto. Of those blessed few, they obviously have at least one other native language, otherwise they'd be completely cut off from society.

And by the same token, English is popular as a second language due to network effects and the benefits learning it can confer (read: better economic opportunities) and little to do with its regularity. A lot of people have had the experience of learning a bit of Spanish and realizing that English's spelling system is atrociously irregular and we gain nothing by having so many spelling rules that have so many exceptions they can hardly be considered "rules". In fact, English's spelling used to be much more regular, it's just that our pronunciations have shifted a lot over time while the spelling has remained relatively static.

This is all tangential to your larger point, I just like talking about this kind of thing.

    while(n < busy_bever(10))
        n++

I think the point is that even though one can't determine loop termination for all loops (easily provable), there are a huge number of useful loops that do useful work and for which you can prove properties like termination (and other static properties).

Exactly! If the loop doesn't terminate, then you obviously cannot show it. But if it does, then you should be able to (even if that requires some changes to help the tool)

I don't think this is true for all loops either - some can be proven to never terminate, just like some can be proven to terminate. And some can't be proven either way.

    while(calculate_pi_stream(10 /* substring length */) != 0987654321);

Hopefully, though, termination of your program does not depend on this ... otherwise could be a long wait!

But this is of a theoretic interest. In practice the verifier says: "I can't prove that this function will terminate within (some reasonable window), program rejected". And this is what's actually needed: a program that provably has certain properties, where an automatic proof is tractable.