Re: forward function definitions

From: Sven LUTHER (luther@maxime.u-strasbg.fr)
Date: Mon Jun 14 1999 - 12:55:38 MET DST


Date: Mon, 14 Jun 1999 12:55:38 +0200
From: Sven LUTHER <luther@maxime.u-strasbg.fr>
To: Junbiao Zhang <junzhang@ccrl.nj.nec.com>, caml-list@inria.fr
Subject: Re: forward function definitions
In-Reply-To: <Pine.GSO.4.10.9906091354050.14576-100000@flame>; from Junbiao Zhang on Wed, Jun 09, 1999 at 02:38:22PM -0400

On Wed, Jun 09, 1999 at 02:38:22PM -0400, Junbiao Zhang wrote:
> Hi,
>
> We're developing a fairly large system with multiple function
> definitions. It's inevitable that some functions may call other functions
> defined later(may not even be recursive calls as in the case of
> Sys.Signal_handle). My question is: how do I solve such a problem which is
> extremely trival in other languages? Thanks.

If the two functions are in different modules, just provide a interface file
for them, and it should work ok but can cause some linker problems.

2 clean way of doing this are :

* use the later called function as a parameter to the first called function :

  let register_signals_arg f = Sys.signal Sys.sigalrm (Sys.Signal_handle f)

  ...
  
  let a sigid = ...
  let register_signals = register_signals_arg a
  
* Or you could define all this in the form of a module functor :

  module type XXX = sig val a : id -> ... end
  module Make_M (X : XXX) = struct
    let register_signals = Sys.signal Sys.sigalrm (Sys.Signal_handle X.a)
         end
  module ARG = struct
    let a sigid = ...
         end
  module M = Make_M ARG
  open M
        
Friendly,

Sven LUTHER



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