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Re: [Caml-list] Improving OCaml's choice of type to display
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Date: 2009-10-09 (16:52)
From: Yaron Minsky <yminsky@g...>
Subject: Re: [Caml-list] Improving OCaml's choice of type to display
I do basically think of this as a deficiency in the compiler as opposed to a
deficiency in core (although it's hardly a major deficiency in the
compiler).  Signatures, modules and functors are an important part of the
language, and if you want to use them in a significant way, then you will
end up having multiple paths to get to the same type.  OCaml's algorithm for
choosing the type to display is somewhat unfortunate in this regard.

If you have a design approach that simultaneously makes good use of
functors, modules and signatures and makes OCaml's type-to-display-selector
happy, I'd be very interested in hearing it.

Finally, the specific point you make argues against the specific heuristic
(smallest type name) I proposed, but not against all other heuristics.
Another heuristic which I think has some potential is choosing the type name
with the smallest number of dots.  (also, as a matter of personal
preference, in the case that you outline, I would prefer the answer of "int"
to "color", but that is just a coincidence, of course.)

To be clear, some of this stuff can be made better by using signature
functors, but that has its own problems in terms of messiness and
boilerplate.  That said, I have half a mind to write a syntax extension to
clean that up, and switch over to signature functors, for this and other
reasons.  That said, signature functors only clean up a little bit of the


On Fri, Oct 9, 2009 at 10:18 AM, Damien Guichard <alphablock@orange.fr>wrote:

> Hi Yaron,
> I think you better think twice about the problem in general (rather than
> the particular needs of Core) before proposing some controversial type
> display improvement.
> Imagine my code is:
>   type color = int
>   let black : color = 0
> Then, following your proposition, evaluating *black* should give me an *
> int* rather than a *color* because *int* is shorter and therefore nicer.
> So, now, what's the point in the *color* type declaration ?
> There is none, type aliasing becomes useless because you can't expose it.
> Call me crazy but i whish i can use more than 3 characters as a type name.
> So you want it to be displayed as an *Int.t* rather than an *
> Int.comparable* ?
> Then just declare it as *Int.t* rather than *Int.comparable*, or choose
> another shorter name, it's not an OCaml issue, its' a Core issue.
> (obviously it would really help if no english word would be more than 6
> characters but Ocaml can't be blamed for that)
> I mean, when designing an elaborate software library, you have to make
> choices, and often, no matter how good OCaml is, some choices will be
> compromises. You have to pick the lesser between several evils and live with
> it.
> I have learned that when programming Ocaml-Idaho<https://forge.ocamlcore.org/projects/ocaml-idaho/>,
> suddenly module names become longer, module types become more composited,
> data types become more subtle, and so on and so on...
> Blaming OCaml is a too easy path.
> At one certain point you have to face the verbosity *you* have created and
> decide whether the additionnal expressivity worths the price.
> If you think it does then it's ok, if not then just amend, if amending
> doesn't help then consider refactoring.
> Seek the best expressiveness/verbosity ratio without sacrifying too much
> functionality.
> That's your job as a library designer.
> - *damien*
>  ------------------------------
>  *En réponse au message*
> *de :* Yaron Minsky
> *du :* 2009-10-09 11:58:11
> *À :* Andrej Bauer
> *CC :* caml-list@yquem.inria.fr
> *Sujet :* Re: [Caml-list] Improving OCaml's choice of type to display
> Well, if we're picking heuristics, the fewest number of characters wouldn't
> be crazy either.  Given the choice between Int.t and Int.comparable (which
> are aliases for the same type), I'd prefer to see Int.t.
> y
> On Fri, Oct 9, 2009 at 3:33 AM, Andrej Bauer <andrej.bauer@andrej.com>wrote:
>> On Fri, Oct 9, 2009 at 3:40 AM, Yaron Minsky <yminsky@gmail.com> wrote:
>> > Choosing shorter names.
>> By which you probably mean "the fewest number of dots (module
>> projections)". It might be a bit annoying if the code that prints
>> doesn't know what modules are open. What do the INRIA priests say?
>> Andrej
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