Re: [Caml-list] Re: module typing issue

[Guillaume Yziquel <guillaume.yziquel@citycable.ch>]

Le Friday 25 Mar 2011 à 17:59:41 (+0100), Andreas Rossberg a écrit :
> On Mar 25, 2011, at 17.42 h, Guillaume Yziquel wrote:
> >Le Friday 25 Mar 2011 à 16:46:47 (+0100), Andreas Rossberg a écrit :
> >>I don't think it ever makes sense to define private type
> >>abbreviations in a structure - they are intended for use in
> >>signatures. Just drop the private from your example.
> >
> >Uuh... It does make some sense, sometimes: In bindings, as output of
> >external stubs, and as phantom type arguments for instance...
> >'ever' is
> >somewhat too restrictive.
> 
> Well, fully abstract type definitions are sometimes handy for these
> purposes. But how do private type abbreviations help there?
> 
> /Andreas

type error = private int

external get_error : unit -> error = "zzz"

You get some error level that you can pattern match as an int, and this
also enforces that all values of type error come from a call to
get_error. This is sometimes handy. Depends on your specific use cases
to know if it's really worth it however.

-- 
     Guillaume Yziquel