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[Caml-list] choosing modules at runtime
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Date: -- (:)
From: Sven LUTHER <luther@d...>
Subject: Re: [Caml-list] choosing modules at runtime
On Tue, Sep 24, 2002 at 12:18:49PM +0200, Olivier Andrieu wrote:
>  Henri Dubois-Ferriere [Tuesday 24 September 2002] :
>  >
>  > Say I have a module signature M which is implemented by module structs 
>  > M_1, M_2, M_3, .. M_N.
>  > 
>  > At runtime , depending on some command-line parameters, I will choose one 
>  > of the module implementations (they use different algorithms internally). 
>  > 
>  > This means my main code will be littered with things like
>  > 
>  > if (use algorithm 1) then
>  > M_1.run_algo()
>  > else if (use algorithm 2) then
>  > M_2.run_algo() ...
> 
> You could use local modules :
> 
>  if (use algorithm 1) then
>   let module M = M_1 in
>   M.run_algo() ...
>  else if (use algorithm 2) then
>   let module M = M_2 in
>   M.run_algo() ...
> 
> the point is that the blocks under the `let module .. = ' are the
> same, so you can copy/paste them. You could use some preprocessing
> treatment to make it look better.

But some sort of syntactic sugar could be added to ocaml in order to
handle this properly, could it not ?

Friendly,

Sven Luther
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