Re: [Caml-list] some beautiful OCaml code

[Kristopher Micinski <krismicinski@gmail.com>]

On Wed, Jan 9, 2013 at 3:38 AM, David MENTRE <dmentre@linux-france.org> wrote:
> Hello OCaml experts,
>
> 2013/1/9 Francois Berenger <berenger@riken.jp>:
> I never fully grasped polymorphic variants compared to regular ones
> but I always had the feeling the polymorphic variants where less safe
> that variants because they would allow more possibility to mix
> unrelated things[1].
>


I would say that it's not that polymorphic variants are less safe, but
they can occasionally be more painful, because of the explicit type
signatures, and because of type inference you can end up with some
ugly errors.  It's typically recommended that when you use polymorphic
variants you use explicit annotations.

I suppose they could be unsafe if, say, you had two similarly named
constructors with the same signature that had different semantics
between different modules.  But that would probably be bad style to
begin with.

There's a StackOverflow guide on when to use polymorphic variants, I
agree with the answer:

http://stackoverflow.com/questions/9367181/variants-or-polymorphic-variants

Kris