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From: jvl@ocsystems.com (Joel VanLaven)
Subject: Re: Question on modular types
Date: 1997/01/06
Message-ID: <1997Jan6.162846.37787@ocsystems.com>#1/1
X-Deja-AN: 208104567
references: <01bbfa96$66d516a0$8d2d5c8b@jerryware>
organization: OC Systems, Inc.
newsgroups: comp.lang.ada
Date: 1997-01-06T00:00:00+00:00
List-Id: <comp.lang.ada>


  I think I know what the confusion is.  The problem is that -1 is not a
literal!  -1 is actually -(1).  1 is a perfectly valid uint and the "-"
operator is the modular "-" and so reduces the result back into the valid
range.  The problem really comes from the problem that we humans take -1
to be a literal but the language doesn't.  I have been confused by that
a few times myself, but in cases where it was more obvious what the problem
was (subtyping an integer type and then not finding the "-" operator).

-- 
-- Joel VanLaven