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From: Duncan Sands <baldrick@free.fr>
Newsgroups: comp.lang.ada
Subject: Re: Hashing on System.Address
Date: Tue, 14 Jun 2005 09:23:48 +0200
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Date: 2005-06-14T09:23:48+02:00

Hi Mark,

> You can always convert a value of type System.Address to a value of a
> signed or modular (implementation-defined) type. That should help when
> you want to hash it into a value of type Hash_Type.

yes that helps - thanks for the suggestion.  In fact that is what I'm already
doing.  The problem is the next part...  That can be simplified to: I have two
modular types (binary modulus), but I don't know their modulus.  Values of
the first type should be hashed into values of the second type.  This can be
done (I've done it) but somehow the code is much more horrible than I feel
it should be.  One annoying point is that a program with a static expression
that would raise Constraint_Error is illegal, even if you would never get to the
Contraint_Error raising part in run-time.  If you don't understand the relevance
of this remark, try to code this kind of hash thing yourself and you will soon
see :)

Thanks again,

Duncan.