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by marktangotango 4256 days ago
I really liked SML and wanted to use it in anger after reading "ML for the working programmer" and "Purely functional data structures" (excellent functional programming books by the way) but just couldn't due to the lack of libraries as you say. For me the object system on Ocaml was just too much. Tis a pity.
2 comments
Raphael_Amiard 4256 days ago
> For me the object system on Ocaml was just too much

What do you mean by that ? The current consensus about the object system in OCaml is "don't use it", even if there might be cases where it will describe your system better.

The standard library (both the real stdlib and Jane Street's Core library) don't use objects so you can pretty much ignore this part of the language if you want to.

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avsm 4256 days ago
There's nothing wrong with objects or classes in OCaml -- it's just that most problems can be expressed using a simplest abstraction technique such as modules. OCaml has steadily improved in every recent release to further reduce the set of problems that need objects (open types, GADTs, first class modules, destructive substitution in module types).

For problems where objects and classes are a good fit (e.g. something requiring open recursion), then OCaml objects are fine and sound. They are used quite nicely in CIL for implementing the visitor pattern, and I like them in the Lablgtk OCaml bindings as well. They also provide a nice bridge to foreign code in OCamlJava and js_of_ocaml when compiling to platforms that make more use of objects.

It's worth noting that class types and object types are distinct in OCaml, so you can often use objects without involving classes at all. This is explained in Real World OCaml: https://realworldocaml.org/v1/en/html/objects.html

Not using OCaml because it possesses an optional object and class extension is a little strange. It never really gets in the way...

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marktangotango 4256 days ago
Since that is the 'current consensus' as you say, it seems like the ocaml community converged on the opinion I formed 10 years ago. But it wasn't necessarily the consensus then.
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Raphael_Amiard 4256 days ago
Ok, makes perfect sense !
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pjmlp 4256 days ago
I remember reading that book on my crossings over the tagus river in Lisbon, after we got introduced to Caml Light.

Time flies!

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