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From: Paul Rubin <no.email@nospam.invalid>
Newsgroups: comp.lang.ada
Subject: Re: 64-bit unsigned integer?
Date: Wed, 28 Feb 2018 02:17:51 -0800
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Date: 2018-02-28T02:17:51-08:00
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"Randy Brukardt" <randy@rrsoftware.com> writes:
> The problem is simply one of language definition; there is no way in
> the Ada language to get overflow for an unsigned type... These days,
> we're moving away from adding any more kinds of types; everything new
> will be a library much like the containers

That seems unfortunate.  I hope the libraries can be implemented in a
way that don't cause runtime overhead.  C unsigned ints wrap around but
that is bogus since it kills the invariant that n+1 is always greater
than n.  GHC has a Word type that wraps around, for when you want
wraparound, but Integers are (arbitrary precision) integers.  (Plus
there is also an evil and unsafe machine-word Int type).

Having an unsigned int type that 1) uses all the bits in the machine
word, and 2) errors on overflow, plus a separd Word type that wraps
around, seems like the right way to do things.  Oh well.