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A look back on OCaml since 2011 (ocamlpro.com)
131 points by andrenth 22 days ago | hide | past | web | favorite | 28 comments

My own retrospective... been using OCaml in a production compiler on obscure UNICES since 3.08 (> 15 years!). Pretty seamless, simple updates, everything kept working, lights are still on. I think source changes were required ~3 times, so amazingly stable from my POV :)

What kind of compiler is it? What does it compile?

Are you the only person who has worked on it?

It compiles a “C# class”-looking DSL to GNOME GObjects, pushing all the ugly boilerplate (I’m aware there are newer ways to do it that have appeared in the last 15 years :)) into the generated code. And nowadays I’d call it a transpiler, but...

It was written by a teammate in 2004 (Frenchman, obviously!) and I’ve owned it since. A number of people have submitted features, etc. It’s fairly straightforward and OCaml wasn’t really a barrier to entry for any of the contributors.

edit: I should have said “source changes due to OCaml upgrades” above to be more clear.

Three things left for the full glory: better Windows support (without MinGW/Cygwin hacks, or WSL), better debugging and profiling (see DWARF PRs in GitHub repository), and, of course, multicore. Looking forward to more OCaml and faster OCaml.

> multicore

what's the state of this nowadays?

> better Windows support

couldn't agree more - they can learn on Go's lessons (the language didn't get much traction until they added Windows support).

4.09 (which has just been released) includes a number of changes that are being introduced soley to ease the merging of multicore.

4.10 will also include a recently merged, large change for multicore support: https://github.com/ocaml/ocaml/pull/8713

The plan is to land multicore in trunk through a series of smaller chunks such as #8713

> 4.09 (which has just been released) includes a number of changes that are being introduced to ease the introduction of multicore.

Ocaml multicore has been on the tablet since ... pretty much the dawn of time. It's save to call it vaporware or the duke nukem forever of Ocaml.

The perfect is the enemy of the good.

multicore is still getting developed. you can watch the repo at https://github.com/ocaml-multicore/ocaml-multicore

It's been in development for more than 5 years and looks a bit like a boondoggle though, as the goal is not just to remove the GIL and provide "native threads" but

> use algebraic effects to compose concurrency and supports parallelism through domains and incremental GC. Rather than adding a specific multicore scheduler into the runtime system, we’re providing the minimum required toolset in the form of pluggable schedulers.

They're doing lots of great heavy lifting to get effects and handlers into a production language, and I don't think it's fair to write them off like this. Yes, it's hard, but they seem to be making positive progress.

> They're doing lots of great heavy lifting to get effects and handlers into a production language

Sure, but at the end of the day what it means is 5 years into the effort OCaml still as limited threading-wise as it was at the start of the effort. And that is what most users (and non-users) care about in a world where 2/4 is your mobile baseline and where AMD's R3-3300G is expected to be 6/12 for $99.

> boondoggle

Care to elaborate?

Go didn’t get much traction until they added Windows support? I could believe that Go began to take off around the time that Windows support was added, but that seems more of a coincidence than a cause. How many deployments are running on Windows, anyway?

Multicore and a modern GUI library will win me over.

I'd be happy with a regex engine with negative look-aheads.

i would say an update to the std lib to bring LWT into the language. something as simple as reading a file without an external lib is verbose

Love a good cheatsheet that actually respects the concept of being a SINGLE, fixed-layout page: http://www.ocamlpro.com/wp-content/uploads/2019/09/ocaml-lan...

It's something of a lost art in the paperless and HTML era of documentation.

Great to see OCaml picking back steam after a few slow years \o/

I use OCaml for my everyday development. The main thing OCaml really needs is modular implicits.

What are modular implicits?

As a layman I would describe them as implicits like in current Scala [0] but better (easier to reason about). One thing which they allow is ad-hoc polymorphism like typeclasses.



[0] https://scala-lang.org

The ML programming language is known for its advanced module system. First, you have structured, which are your traditional idea of a module. Structures define types and data. Signatures describe the interface of a module and are like the module's "type." By making types abstract or not mentioning members, signatures achieve encapsulation of modules. Finally, you have functors, which are functions from modules to modules. The parameter is constrained by a signature, and the client can pass any module that conforms to the signature to get an output module that uses the passed module in its implementation.

The module system is used when a type must support certain operations. For example, the Set module (https://caml.inria.fr/pub/docs/manual-ocaml/libref/Set.html) defines a signature called OrderedType for types equipped with a comparison function, and any module that implements OrderedType can be used to make a set.

Notably, ML modules differ from Haskell typeclasses because more than one module can exist for the same combination of types. However, you must pass ML modules explicitly, whereas typeclass instances are passed implicitly. So, ML modules have more power than typeclasses, but at the cost of convenience.

Here is an example where modules are used to make a set:

    module LtInt = struct
      type t = int
      (* Use built-in polymorphic comparison *)
      let compare = compare

    module GtInt = struct
      type t = int
      let compare lhs rhs = compare rhs lhs

    module LtIntSet = Set.Make(LtInt)

    module GtIntSet = Set.Make(GtInt)
However, modules can quickly get inconvenient:

    module type Monoid = sig
      type t
      val op : t -> t -> t
      val e : t

    module Addition = struct
      type t = int
      let op = (+)
      let e = 0

    module Multiplication = struct
      type t = int
      let op = ( * )
      let e = 1

    module FoldLeft (M : Monoid) = struct
      let fold_left = List.fold_left M.op M.e
Here, it's probably less verbose to just pass the operation and starting value directly to List.fold_left than to use modules! Debatably, this is as equally inconvenient as Haskell's newtype solution to multiple instances, but if there is only one instance, typeclasses are much cleaner to use.

Modular implicits are a long-awaited feature that will allow ML modules to be passed implicitly.


They did a pretty good job shepherding it, although I'm still not too fond that the current trend is fueled by the Javascriptification of all the things.

Sadly, meanwhile "Standard" ML is languishing in academia...

At least Standard ML has multicore: https://www.polyml.org/.

I don't follow. How do you feel is OCaml javascriptified?

I think he’s referring to ReasonML. Which plenty of OCaml developers dislike, but managed to build a healthy ecosystem in a short amount of time.

Not GP, but they probably were referring to ReasonML, a JavaScript style syntax for OCaml that primarily targets the web.

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