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Reason: A new interface to OCaml

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Re: Reason: A new interface to OCaml

#221

Post by int_19h »

ufo wrote: post #168
jordwalke wrote: post #165

Earlier quoted context omitted.

I suspect the syntax of `<-` (or lack thereof) will be a common topic of discussion. Let's see how various audiences respond to this change and then discuss if we'd like to restore `<-` for mutation. Personally, I don't use a ton of mutations in my code so I have less at stake and if there's anything we can do to appeal to a wider audience, I'm inclined to give it a shot.

Maybe I'm too used to Ocaml to comment but I think using `=` for mutation is a bit misleading because it might make it appear that `x.mutablefield = bla` and `let x = bla` are the same thing, which is the case for typical imperative languages (but definitely not for Ocaml). BTW, one thing that I do find awkward about Ocaml's syntax is the difference between := and <-. Dunno if its possible to unify them in a sane man…

F# doesn't unify them, but it makes := largely redundant by letting you do "let mutable ...", and then assign to it with "<-" - so you simply don't need to use refs if you just need some mutable data (you still need them if you want to have a closure mutate something it closed over).

Re: Reason: A new interface to OCaml

#222

Post by LeonidasXIV »

jordwalke wrote: post #151
mhd wrote: post #146

I hope this doesn't sound like trolling, but JavaScript's syntax is now a selling point? I kinda-sorta get the reason why people want an actual JavaScript stack on the backend, but I never heard that syntax/semantics brought people from e.g. Rails to Node. Sure, OCaml isn't even the nicest syntax in the ML family, but I'm not sure whether that's worth it, especially considering that almost any "X-like" language often…

Jordan here (I work on Reason) I've mentioned elsewhere that the primary goal for now was to get the tooling automated as much as possible, so that when we receive common feedback, we can adapt to that feedback and trivially migrate people's code forward. I don't think JavaScript's syntax is a selling point and I am someone with a lot of JavaScript experience. I also don't think that OCaml's syntax today is a selling…

I am not a fan of introducing curly brackets in a similar way I am not a fan of curly-bracketisms in F#, it makes for a clumsy noise to a relative distraction-free language like OCaml. It feels like trying to get Algol-family programmers on board, whereas OCaml users have been using ( and ) as well as begin/end since a long time.

But an advantage I see with the new comment syntax is that there are is that there is no ambiguity what the hell (*) is. At least this.

Re: Reason: A new interface to OCaml

#223

Post by LeonidasXIV »

MichaelGG wrote: post #100

I started off a bit skeptical with the What's OCaml's status with multithreading? Are there any proposals for more flexible operators, so there doesn't need to be different operators for different numerics? (F# solves this by allowing inlined functions.)

If there is one single thing from F# I would like to have in OCaml it is the whitespace syntax. I can write nice OCaml, but I often need to exploit corners in the grammar and cheating around with precedence and @@ to get my code to not be full of clumsy parens, anonymous functions etc.

Re: Reason: A new interface to OCaml

#224

Post by tom_mellior »

weberc2 wrote: post #11
e_d_g_a_r wrote: post #2

I for one welcome the syntax. I run the OCaml meetup in Silicon Valley and syntax is definitely an issue for newcomers. This makes it easier for other programmers to instantly just jump into OCaml/ML rather than ask about what is `in` or what is `let foo = function`, etc etc. EDIT: Hosting a Meetup this friday at 6pm in San Francisco about Reason and how to instantly start using it, http://www.meetup.com/sv-ocaml/eve…

This definitely makes me feel more warmly toward OCaml. Syntax has kept me away in the past. It's silly, but it's really hard to evaluate a language if you can't read the examples.

> It's silly, but it's really hard to evaluate a language if you can't read the examples.

No, this is not a silly notion. But I don't think the difference Reason makes is as big as you think. I mean, I don't really believe that you can read this:

  let foo = if (cond) { x } else { y };
  foo + 1
but not this:

  let foo = if cond then x else y
  in
  foo + 1

Re: Reason: A new interface to OCaml

#225

Post by zem »

jameshart wrote: post #62

Wonder if this project has anything to do with Eric Lippert's move to Facebook ( https://ericlippert.com/2016/02/08/facebook/ - Eric has also been producing a series of blog posts implementing a Z-Machine interpreter in OCaml to run mini-Zork on, starting here: https://ericlippert.com/2016/02/01/west-of-house/ ). Eric was on the C# compiler team at Microsoft and previously worked on JScript.

damn, i recently started writing a z machine interpreter in ocaml, and now i both really want to read those posts and really don't want to be influenced by lippert's design decisions before i've at least gotten my own project solidly underway.

Re: Reason: A new interface to OCaml

#226

Post by LeonidasXIV »

gaius wrote: post #190
cvik wrote: post #180

Earlier quoted context omitted.

OCaml, like SML, have the syntax for defining their own operators. |> is defined, to my knowledge, both in the standard prelude and in core.

Since Ocaml 4 if I remember correctly

4.01 to be exact. Along with @@, which is kinda comparable to $ in Haskell.

Re: Reason: A new interface to OCaml

#227

Post by tom_mellior »

ubertaco wrote: post #172

As excited as I was to see a big new thing in OCaml-land, I have to say my excitement died down as I read on. I don't really see most of the changes as improvements. Having a different, explicitly-noticeable syntax for mutable updates is nice, because it calls out mutability (which should be used sparingly). I don't see extra braces as necessarily an improvement, given that OCaml's local scopes are already quite unam…

> I actually don't like ambiguity between type annotation and value assignment in my records. It's clear in current OCaml that {a: int} is a type declaration and {a = 1} is a value declaration/assignment.

Wild guess: Due to moving to a brace syntax for blocks and '=' for assignments, they needed to move to colons to disambiguate something that already used braces and '='. That is, something like this:

  let x = ref 0;
  type record = { x: int };
  if (cond) { x = 1 } else { x = 2 }
might read either as creating a new record value or as writing throught the reference. (Again, just a guess.)

EDIT: All that said, I agree with you. OCaml's syntax is meh, but moving it closer to brace languages makes it worse, not better. Some of these changes actually move closer to Haskell (constructors without parens, yay!), and those are the changes I like.

Re: Reason: A new interface to OCaml

#228

Post by LeonidasXIV »

thedufer wrote: post #193
cwyers wrote: post #117

I really wish they'd taken the pipeline (|>) operator from F#, if they were going to rework OCaml.

As others have noted, the pipeline operator already exists in OCaml. And even if it didn't, you can define it pretty easily: let (|>) x f = f x

Can be shortened to

    let (|>) x f = "%apply"
which utilises some language magic and is probably faster.

Re: Reason: A new interface to OCaml

#229

Post by LeonidasXIV »

oblio wrote: post #109

Has anyone here built something say, over 10k lines in Ocaml? How is the development experience? IDEs, debuggers, linters, deployment, etc.

I was working on a 30kloc compiler written in OCaml:

- No IDE, I was happily using Vim but many of my coworkers were using Emacs. What helped a lot was Merlin, so I could print the types of the identifiers. This was much more useful than any REPL or IDE I have ever used.

- Debuggers: didn't use much, ocamldebug was an okay experience at best

- Linters: did not use. Most of the LOC were simple enough to just be obvious.

- Deployment: it was a Makefile which took about a minute to build the compiler from scratch. I guess that by using a proper OCaml build system we could've sped things up by requiring less recompilation but it was fine. In the end a binary fell out and could be used however.

I liked the development experience a lot, once it compiled it was reasonably clear that it would work as expected, expanding the compiler was very nice since every time I added a new variant, the compiler complained where I need to add code and then it just worked. We had the advantage that we already had our own mini standard library, so most missing utility functions were already in place when I joined.

Re: Reason: A new interface to OCaml

#230

Post by Gonzih »

Cyph0n wrote: post #48

This looks very interesting. I've always had OCaml in mind but never actually got around to using it in a project. Facebook could have done a better job describing what exactly this is, but they do provide a good overview at the end of the page (strangely!) [1]. In summary, Reason [2] is a new language (correction: interface to OCaml) that shares a part of the OCaml compiler toolchain and runtime. I don't know of any…

I always liked ML family PLs, but my problem with OCaml is lack of good stdlib. This is why I never invested a lot of time in to it sadly. Reasons looks like a more solid out of the box ocaml distribution which I actually like a lot. Will play with it.
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