From: simpson@saturn.ind.trw.com (Scott Simpson)
Subject: Re: Ada functions versus arrays (i.e. () vs [] )
Date: 2 Mar 90 23:46:41 GMT [thread overview]
Message-ID: <3011@trwind.UUCP> (raw)
In-Reply-To: 6281@bd.sei.cmu.edu
In article <6281@bd.sei.cmu.edu> firth@sei.cmu.edu (Robert Firth) writes:
>In article <608@software.software.org> blakemor@software.org (Alex Blakemore) writes:
>
>>I agree that side effects are best avoided - they definitely mess up this
>>scheme. I assume the language designers left them in for the
>>very few times when they are justifiable (e.g. next_random_number).
>>Quite possibly a language design error forced on them by C programmers :-)
>
>As I recall, we left them in for the same reason Algol-60 did: it is
>impossible to rule out the bad uses without also ruling out the good
>ones. It is the responsibility of the programmer not to employ the
>bad uses.
Meyer summed this up much more beautifully I think in his book
Object-Oriented Software Construction when he said that side-effects
are harmless when they only affect the *concrete* state and not the
*abstract* state. This division is important. See section 7.7.3, page
135 of OOSC.
Scott Simpson TRW Information Networks Division simpson@trwind.trw.com
next prev parent reply other threads:[~1990-03-02 23:46 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
1990-02-20 16:13 Reasons for dropping Ada Ted Holden
1990-02-20 21:04 ` Richard S D'Ippolito
1990-02-20 23:03 ` Reasons for keeping Ada David Kassover
1990-02-21 0:40 ` Clement Pellerin
1990-02-21 19:02 ` Reasons for dropping Ada Loren Louis Hart
1990-02-22 16:07 ` Mike Coffin
1990-02-22 17:01 ` if UNIX then USE_C ?? (was: Reasons for drop) Dennis M. O'Connor
1990-02-22 21:51 ` Barry Margolin
1990-02-23 19:34 ` Loren Louis Hart
1990-02-25 19:58 ` David Kassover
1990-02-26 12:45 ` John F Nixon
1990-02-26 18:28 ` David Kassover
1990-02-26 20:55 ` John F Nixon
1990-02-26 22:00 ` David Kassover
1990-02-27 18:55 ` Jeremy Epstein
1990-02-28 1:19 ` Alex Blakemore
1990-02-28 18:56 ` Ada functions versus arrays (i.e. () vs [] ) Richard A Hammond
1990-03-01 3:25 ` Alex Blakemore
1990-03-01 13:11 ` Robert Firth
1990-03-02 10:56 ` Mike Harrison
1990-03-02 23:46 ` Scott Simpson [this message]
1990-03-02 10:42 ` Mike Harrison
1990-03-06 19:13 ` Erland Sommarskog
1990-03-08 14:21 ` John Goodenough
1990-03-14 18:19 ` if UNIX then USE_C ?? (was: Reasons for drop) RCAPENER
1990-03-01 0:29 ` David Kassover
1990-03-01 15:11 ` Steve Tynor
1990-03-01 18:29 ` David Kassover
1990-03-02 0:19 ` Robert D. Houk
1990-02-28 19:51 ` Andy DeFaria
1990-02-20 22:21 ` Reasons for dropping Ada Jeffrey M. Schweiger
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