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From: Ludovic Brenta <ludovic@ludovic-brenta.org>
Newsgroups: comp.lang.ada
Subject: Re: Implementing an Ada compiler and libraries.
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Date: Thu, 10 May 2007 18:37:52 +0200
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Date: 2007-05-10T18:37:52+02:00
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Stefan Bellon <sbellon@sbellon.de> writes:
> Gautier wrote:
>
>> - time stamps to check need of recompilations
>
> I've always wondered about the focussing on time stamps. I think the way
> to do it would be to calculate a hash sum (md5, sha1, ...) on the token
> stream without comments. This way you wouldn't have to recompile if you
> do layout and commentary changes, and even if you touch the file, you
> don't inadvertently trigger a recompilation.

That's what GNAT does, only it uses a simple checksum for performance
reasons.  Calculating the checksum and comparing it with the one in
the library (.ali files in the case of GNAT) has to be faster than
recompiling the file.

-- 
Ludovic Brenta.