Path: utzoo!yunexus!geac!daveb
From: daveb@geac.UUCP (David Collier-Brown)
Newsgroups: comp.lang.c
Subject: Re: noalias, again
Summary: Public Policy
Message-ID: <2479@geac.UUCP>
Date: 22 Mar 88 17:26:08 GMT
Article-I.D.: geac.2479
Posted: Tue Mar 22 12:26:08 1988
References: <7712@apple.Apple.Com> <7485@brl-smoke.ARPA> <10731@mimsy.UUCP>
Reply-To: daveb@geac.UUCP (David Collier-Brown)
Organization: The Geac "C is a Living Language" Association.
Lines: 46


>In article <7485@brl-smoke.ARPA> gwyn@brl-smoke.ARPA (Doug Gwyn ) writes:
>>Basically, "noalias" is ... [long description deleted]
>>I think I got that substantially right, although I may have messed
>>up a few details.  Hey, I don't plan to use [noalias]!

In article <10731@mimsy.UUCP> chris@mimsy.UUCP (Chris Torek) writes:
>The point is that the standard library is now bestrewn with `noalias'
>declarations; these declarations make promises to the compiler; and you
>as a programmer are obligated to keep these promises, so you must know
>what they are and, when necessary, change your code where it violates
>them.  The C library you have been using makes no such promises.  There
>has been nothing to violate; now there is.

  We now have a **Public Policy** question: how much do we dare
change a language to keep it alive (ie, meet new real-world needs),
if by doing so we change the meaning of the language and thereby
existing programs written in the language.

  Languages, unlike data structures, do not evolve without
considerable effort.  How much must we expend?

	Some people will say "none", and require the language to be
    backwards-compatible[1].
	Some will say "a bit", and change new programs to fit the
    new requirements.
	Some will say "a moderate amount", and change some old
    programs when they need maintenance.
	Some will say "as much as you like", and throw away old
    programs if they don't meet new standards[2]

  Is this an area a standards body wishes to become involved in?
And if not they, who?

--dave

[1] C++ is backwards-compatible and good. C "=op" operators are
    backwards-compatible and bad.  (They're also gone.)
[2] People did this when "structured programming" came in, because
    it was worth it.  How many spagetti programs do **you** maintain
    today?
-- 
 David Collier-Brown.                 {mnetor yunexus utgpu}!geac!daveb
 Geac Computers International Inc.,   |  Computer Science loses its
 350 Steelcase Road,Markham, Ontario, |  memory (if not its mind) 
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