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From: barmar@think.COM (Barry Margolin)
Newsgroups: comp.lang.c
Subject: Re: swaps with arrays
Message-ID: <8228@think.UUCP>
Date: Wed, 9-Sep-87 17:41:54 EDT
Article-I.D.: think.8228
Posted: Wed Sep  9 17:41:54 1987
Date-Received: Fri, 11-Sep-87 05:33:17 EDT
References: <2376@zeus.TEK.COM> <110@umigw.MIAMI.EDU>
Sender: news@think.UUCP
Reply-To: barmar@godot.think.com.UUCP (Barry Margolin)
Organization: Thinking Machines Corporation, Cambridge, MA
Lines: 29

In article <110@umigw.MIAMI.EDU> steve@umigw.UUCP (steve emmerson) writes:
>Well, I can't speak for everyone ;-), but if I was given a generic swap
>routine that only worked on a subset of all possible data types ...
>well, I might consider it very useful, but I wouldn't consider it
>generic.  Someone please correct me if I'm wrong, but I believe a
>"generic" routine is one that will work for any type of input (with a
>caveat for the above example that the two arguments have the same
>type).  Now, in the original article, Walter Bright had the word
>"generic" in quotes.  Perhaps he was thinking along these lines and
>ment to imply a "pseudo" or "quasi" generic routine (Walter?).

Several people have mentioned that the answer is that array names are
constants.  My point of view on this subject, and I think it directly
addresses the point quoted above, is that the "genericity" of the swap
macro is consistent with the rest of the language.  In C assignment is
generic, but you cannot use an array name as the target of an
assignment.  I don't know why anyone would expect anything in C to
automatically operate element-wise on an array, as it happens in no
other situation.  I'm not an experienced C programmer (although I know
it well enough that I knew why 'if *buffer == *"LDA"' was wrong in the
recent query), but I would expect such people to be SURPRISED when
things automatically handle arrays!

---
Barry Margolin
Thinking Machines Corp.

barmar@think.com
seismo!think!barmar