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[Caml-list] Resource acquisition is initialization
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Date: -- (:)
From: Blair Zajac <blair@o...>
Subject: Re: [Caml-list] Resource acquisition is initialization
Xavier Leroy wrote:
> 
> > One of the nice things about C++ and Java is that with properly
> > designed classes, you don't need to worry about freeing resources
> > in complicated code, because the when the objects go out of scope
> > either normally or via an exception, they will clean themselves up.
> 
> I believe this is a C++-specific idiom.  Java doesn't have
> destructors, just finalizers that are called asynchronously by the
> GC.  OCaml also has GC finalization (see below).
> 
> > Given that Ocaml has objects, it would be useful to have this
> > idiom available to us.  Is there a way to implement it, rather
> > than just waiting for the garbage collector?
> 
> Yes: higher-order functions.  For a file:
> 
> let with_file_in filename action =
>   let ic = open_in filename in
>   try
>     let res = action ic in close_in ic; res
>   with x ->
>     close_in ic; raise x
> 
> For a mutex:
> 
> let synchronize mut action =
>   try
>     Mutex.lock mut;
>     let res = action () in
>     Mutex.unlock mut;
>     res
>   with x ->
>     Mutex.unlock mut;
>     raise x
> 
> You get the idea.

Thanks for all the answers everybody sent, both on and off list, it's
much appreciated.

Best,
Blair

-- 
Blair Zajac <blair@orcaware.com>
Plots of your system's performance - http://www.orcaware.com/orca/
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