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From: Marius Amado Alves <amado.alves@netcabo.pt>
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Subject: Re: Mneson announcement and help request
Date: Wed, 02 Jun 2004 04:06:02 +0100
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Date: 2004-06-02T04:06:02+01:00

> In general, I hate to see code that uses exceptions for normal control flow
> processing. It certainly appears to
> me that your code that makes use of the various For_Each_XXX type procedures
> uses an exception
> raise to terminate the search when "done".

Yes, that is a controversial style. Some like it, some don't. Note the 
planned Ada standard containers are in this style. If it is found to be 
a performance hitter in Mneson I'll say change it. But my experiments so 
far have shown no speed loss from there. At least with GNAT. I'm more 
inclined to earn speed with inlining. But to do that properly reliable 
profiling is also required.

> On compilers that implement zero-cost-exceptions of some sort, the "cost" is
> high (or higher) on each
> exception occurance.
> 
> On compilers that do not implement it, the presence of an exception handler
> causes some overhead.

So that's how they do it :-)
Yes, we'll have to analyse the algorithms in view of this.

I'll be delighted to answer any questions on Mneson design, here or 
privately. I'll also try to improve the documentation soon, including 
design items.