Why GitHub used Haskell for Semantic • Hacker News Board

Re: Why GitHub used Haskell for Semantic

#31

Post by gilbetron » Thu, Jun 06, 2019, 1:28 AM UTC

thrwayxyz wrote: post #23

tathougies wrote: post #6

Earlier quoted context omitted.

I havr never noticed immutable data structures to be more difficult to deal with. For the most part, because of monads and effects and such you can essentially write better imperative code in haskell. Im noy sure why youve decided that haskell is incapable of the syntactic appearance of mutation.

You're lucky enough if you can find a developer who knows mutable data structures outside of SF. If you want immutable ones you need to add a zero to their wage. Most shops aren't prepared for that.

> You're lucky enough if you can find a developer who knows mutable data structures outside of SF.

That's one of the most arrogant statements I've read on HN in quite a while.

Nearly all developers know mutable data structures, it's bread and butter. Immutable ones aren't some exotic life form, it's just that using them effectively (read: efficiently) as mutable ones can be really tough, and leads to more complex code.

You should maybe get out of SF for a bit.

Re: Why GitHub used Haskell for Semantic

#32

Post by phodge » Thu, Jun 06, 2019, 1:28 AM UTC

> An example of this is the concept of resumable exceptions. During Semantic's interpretation passes, invalid code (unbound variables, type errors, infinite recursion) is recognized and handled based on the pass's calling context. ... Porting this to Java would require tremendous abuse of the try/catch/finally mechanism, as Java provides no way to separate control flow's policy and mechanism. And given Go's lack of exceptions, such a feature would be entirely impossible.

Not knowing much about FP, It'd be great to see a more in-depth article explaining this problem domain a bit more and showing some side-by-side examples of Haskell's specialized call sites compared to a Java try/except/finally solution (although Python would be a better procedural exception-based language to compare to)

One of the main reasons I don't care much about Haskell is because without any side-by-side comparisons of Haskell vs I don't understand what the Haskell advantages are, and I don't know when I'm dealing with a problem space where Haskell would help me.

Re: Why GitHub used Haskell for Semantic

#33

Post by chachachoney » Thu, Jun 06, 2019, 1:30 AM UTC

StavrosK wrote: post #11

jonahx wrote: post #10

Earlier quoted context omitted.

Because in its current form the subject and verb don't agree.

Only in American English. Groups are plural in British English. "The police are corrupt" vs "the police is corrupt".

Can you show an example of an article in a British publication that treats singular corporate entities as plural?

(theregister.co.uk doesn't appear to follow the convention)

Re: Why GitHub used Haskell for Semantic

#34

Post by _bxg1 » Thu, Jun 06, 2019, 1:34 AM UTC

Ixiaus wrote: post #27

_bxg1 wrote: post #4

I'm really curious why Haskell has seen so little adoption in industry. Is it just the difficulty? Or a chicken-and-egg effect with tooling and libraries? One thing I've wondered is if it actually isn't ideal for a lot of cases. FP is beautiful for certain things. But in some domains (or pieces of domains), state and mutation aren't just unfortunate implementation details, but a core element of the problem space. For…

I actually think it's seeing quite a bit of adoption in industry. What I'm seeing is a class of developer that won't learn it or thinks they can't learn it, of course "to each their own", but I truly think Haskell/PureScript/Idris/Agda are onto something remarkable: making the software industry more like an engineering discipline and less of a craft (i.e. like the difference between civil engineering and carpentry).…

Have you used it for anything interactive? All of the above seem to me like natural fits for a pure functional style

Re: Why GitHub used Haskell for Semantic

#35

Post by _bxg1 » Thu, Jun 06, 2019, 1:39 AM UTC

llamathrowaway wrote: post #25

_bxg1 wrote: post #4

I'm really curious why Haskell has seen so little adoption in industry. Is it just the difficulty? Or a chicken-and-egg effect with tooling and libraries? One thing I've wondered is if it actually isn't ideal for a lot of cases. FP is beautiful for certain things. But in some domains (or pieces of domains), state and mutation aren't just unfortunate implementation details, but a core element of the problem space. For…

> But in some domains (or pieces of domains), state and mutation aren't just unfortunate implementation details, but a core element of the problem space True, but I would argue that it is far, far more common for people to writing stateful code to do things that are better done in functional style, than the other way around. This comes from my own experience of learning functional programming in JavaScript (before kn…

> I would argue that it is far, far more common for people to writing stateful code to do things that are better done in functional style, than the other way around.

For sure. But still, there exist cases. Many of them in JavaScript, actually. In my JavaScript UIs I relish every opportunity to write something as a pure function. But I also need to manage a lot of deeply structured, non-homogenous state that's genuinely meaningful to the application. Separating the two is crucial, but both exist. I've really enjoyed MobX, as it allows you to make the most of both types of programming and hook them up together in a cohesive way.

> I think Haskell is not more widely used in the industry because it has a very academic reputation...you are more likely to be perceived as some eccentric scholar or their like.

And yet Clojure has gotten traction :)

Re: Why GitHub used Haskell for Semantic

#36

Post by tottenhm » Thu, Jun 06, 2019, 1:43 AM UTC

"Semantic" looks pretty neat. Are there are previous threads or announcements about Github's goal in developing it (i.e. services for which they plan to use it)?

Re: Why GitHub used Haskell for Semantic

#37

Post by k6k7f7uky8ki » Thu, Jun 06, 2019, 1:44 AM UTC

phodge wrote: post #32

> An example of this is the concept of resumable exceptions. During Semantic's interpretation passes, invalid code (unbound variables, type errors, infinite recursion) is recognized and handled based on the pass's calling context. ... Porting this to Java would require tremendous abuse of the try/catch/finally mechanism, as Java provides no way to separate control flow's policy and mechanism. And given Go's lack of e…

You mean examples like Rosettacode has?

Re: Why GitHub used Haskell for Semantic

#38

Post by kartickv » Thu, Jun 06, 2019, 1:50 AM UTC

_bxg1 wrote: post #4

I'm really curious why Haskell has seen so little adoption in industry. Is it just the difficulty? Or a chicken-and-egg effect with tooling and libraries? One thing I've wondered is if it actually isn't ideal for a lot of cases. FP is beautiful for certain things. But in some domains (or pieces of domains), state and mutation aren't just unfortunate implementation details, but a core element of the problem space. For…

My theory is that the FP folks would have seen more success had they figured out ways to bring their features to mainstream languages, rather than asking people to adopt wholesale their weird languages (from an average programmer's point of view). For example, why can't I annotate functions as lazy? Swift takes one step in that direction, with lazy var, but why not a lazy func or lazy class? Even the lazy var can't be used for local variables.

People are generally more willing to accept incremental changes than an entirely new way of doing things. For good reasons: they're skeptical, availability of talent, tools, libraries, IDEs, help if they run into trouble...

An analogy is the spread of yoga in the west the past decade or two, because it was easy to do so without changing your lifestyle. If Westerners were asked to fly to the Himalayas for a month to learn yoga, how many would have learnt yoga?

Re: Why GitHub used Haskell for Semantic

#39

Post by AnimalMuppet » Thu, Jun 06, 2019, 1:53 AM UTC

_bxg1 wrote: post #4

I'm really curious why Haskell has seen so little adoption in industry. Is it just the difficulty? Or a chicken-and-egg effect with tooling and libraries? One thing I've wondered is if it actually isn't ideal for a lot of cases. FP is beautiful for certain things. But in some domains (or pieces of domains), state and mutation aren't just unfortunate implementation details, but a core element of the problem space. For…

> But in some domains (or pieces of domains), state and mutation aren't just unfortunate implementation details, but a core element of the problem space. For these cases, the FP answer is usually "recompute and replace" (generally with immutable data structures that make this efficient).

It can get worse than that. My problem space has mutable state that is shared between multiple threads. FP's initial answer is "shared mutable state is evil". And they're right! But if that's the nature of your problem, then you're kind of stuck with it.

But the problem with the "recompute and replace an immutable data structure" is that I now have to notify all the relevant threads that they need to replace their reference to the data structure (avoiding race conditions in the process), and that seems at least as nasty as the problems I have doing it the imperative way.

Re: Why GitHub used Haskell for Semantic

#40

Post by MisterOctober » Thu, Jun 06, 2019, 1:54 AM UTC

Ixiaus wrote: post #27

_bxg1 wrote: post #4

I'm really curious why Haskell has seen so little adoption in industry. Is it just the difficulty? Or a chicken-and-egg effect with tooling and libraries? One thing I've wondered is if it actually isn't ideal for a lot of cases. FP is beautiful for certain things. But in some domains (or pieces of domains), state and mutation aren't just unfortunate implementation details, but a core element of the problem space. For…

I actually think it's seeing quite a bit of adoption in industry. What I'm seeing is a class of developer that won't learn it or thinks they can't learn it, of course "to each their own", but I truly think Haskell/PureScript/Idris/Agda are onto something remarkable: making the software industry more like an engineering discipline and less of a craft (i.e. like the difference between civil engineering and carpentry).…

Yep! Another good example: the pretty nifty Postgres API interface postgREST is implemented in Haskell