Re: [Caml-list] duplication implementation/interface

[Judicael Courant <Judicael.Courant@lri.fr>]

Brian Rogoff a écrit :
> 
[...]
> What's the problem with the hack I suggested earlier: put the huge variant
> (and other duplicated types) in a "pure" .mli file (I hate using .ml for
> that) and "open"ing it where you need it, once in the .mli file and once in the
> .ml file? This way you reduce the duplication to two lines.
> 
> I know some people are open-phobes, but I find this use of open to be
> acceptable.
> 

As for open-phobes, somebody gave me a good solution a few days ago: you
can locally define a module with a very short name.

Example : put your type in my_beautiful_type.mli with constructors Node,
Leaf, ..., and where you need it do

module T = My_beautiful_type

then you can use it with a small overhead of 2 chars per use of a
constructor of My_beautiful_type: T.Node, T.Leaf, ...

This is quite elegant IMHO as it makes your code very clear.

As an aside, if you consider applying the same treatment for exceptions
(also duplicated), you need to put them in a .ml file (not a .mli) as a
.cmo is needed for linking (an exception actually creates at run-time a
fresh exception identifier).

Judicaël
-- 
Judicael.Courant@lri.fr, http://www.lri.fr/~jcourant/
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"Montre moi des morceaux de ton monde, et je te montrerai le mien"
Tim, matricule #929, condamné à mort.
http://rozenn.picard.free.fr/tim.html
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