From mboxrd@z Thu Jan  1 00:00:00 1970
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Path: utzoo!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!inmet!stt
From: stt@inmet.inmet.com
Newsgroups: comp.lang.ada
Subject: Re: Non-static constant propagation in
Message-ID: <20600033@inmet>
Date: 10 Jan 90 21:24:00 GMT
References: <1735@petsd.UUCP>
Nf-ID: #R:petsd.UUCP:1735:inmet:20600033:000:790
Nf-From: inmet.inmet.com!stt    Jan 10 16:24:00 1990
List-Id: <comp.lang.ada>


As Robert Firth said, the point of my joke about SQRT on universals
was exactly that the result is not always a rational number.
The definition of Ada does not currently include any operations on universal
reals which produce irrational results.  If we were to add SQRT,
then the cited wording would have to change.  I have no expectation
that SQRT will be added to the set of operations defined on
universal reals, by the way...

S. Tucker Taft
Intermetrics, Inc.
Cambridge, MA  02138

P.S. I wouldn't rule out some clever implementation which could
represent all algebraic numbers "exactly", but it would clearly
have to be more complicated than simply a pair of universal
integers as is used for rationals
(probably a tree structure of some sort, requiring symbolic
evaluation, etc).
-T