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From: dewar@cs.nyu.edu (Robert Dewar)
Subject: Re: Zoo question
Date: 1996/08/25
Message-ID: <dewar.840990532@schonberg>#1/1
X-Deja-AN: 176397006
references: <321207F7.4D24@lmtas.lmco.com> <4v1m7n$8du@zeus.orl.mmc.com>
 <32185D2A.167EB0E7@escmail.orl.mmc.com>
organization: Courant Institute of Mathematical Sciences
newsgroups: comp.lang.ada
Date: 1996-08-25T00:00:00+00:00
List-Id: <comp.lang.ada>


Ted Dennison says, referring to the Zoo example

"...or the check could be placed around the next USE of the value. This could
well be a useful optmization in some circumstances."

This transformation is only allowed if it is semantically invisible, and
hence does not need to enter into a discussion of the semantics of the Zoo
program. note in particular that such a transformation is not permitted
if it changes any external effect, or if it moves a CE outside the
current frame.