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Date: 7 Sep 93 21:56:53 GMT
From: eachus@mitre-bedford.arpa  (Robert I. Eachus)
Subject: Re: How to assign STRINGs?
Message-ID: <EACHUS.93Sep7165653@spectre.mitre.org>
List-Id: <comp.lang.ada>

In article <1993Sep3.181825.920@cfmu.eurocontrol.be> stef@cfmu.eurocontrol.be (
Stef Van Vlierberghe) writes:

   Newsgroups: comp.lang.ada
   Path: linus.mitre.org!linus!agate!doc.ic.ac.uk!uknet!mcsun!ub4b!cfmu!news
   From: stef@cfmu.eurocontrol.be (Stef Van Vlierberghe)
   Sender: news@cfmu.eurocontrol.be (News account)
   Date: Fri, 3 Sep 93 18:18:25 GMT
   References: <25gmc2$3cf@neomimsy.cs.umd.edu> <HILDJJ.93Aug26100909@jupiter.f
uentez.com> <EACHUS.93Aug27152310@spectre.mitre.org>
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   In article <EACHUS.93Aug27152310@spectre.mitre.org> eachus@spectre.mitre.org
 (Robert I. Eachus) writes:

  > Nice going Bob, but you were a bit over-focused on style I guess,
  > I would like to return Better_Ideas on this one :

  >			String'(In_Str_Len+1..Out_Str'LENGTH => Pad_Char);
					  ^^
  > or you get a CONSTRAINT_ERROR.

    Mea culpa.

  > Hey, a new species of bug : off by 2 !   :-)

    Nope!  Old bug species.  Incorrect signs from double negation.  I
originally wrote In_Str_Len..Out_Str'LENGTH-1. (The catenation wipes
the actual indexes, all that matters is the length.)  But I moved the
correction to the first index as less confusing, and the usually
helpful SunAda compiler failed to do the symbolic arithmetic to
eliminate the run-time check.  (Not a compliant, since it catches most
of these cases.)  Next time I post something like this I'll have to
test it, not just compile it.

--

					Robert I. Eachus

with Standard_Disclaimer;
use  Standard_Disclaimer;
function Message (Text: in Clever_Ideas) return Better_Ideas is...