Path: utzoo!utgpu!water!watmath!clyde!cbosgd!ihnp4!homxb!mhuxt!mhuxm!mhuxo!ulysses!allegra!mit-eddie!rutgers!ames!hc!hi!kurt
From: kurt@hi.UUCP
Newsgroups: comp.lang.c
Subject: Re: comma operator
Message-ID: <22902@hi.unm.edu>
Date: 16 Jan 88 23:23:40 GMT
References: <3819@sigi.Colorado.EDU> <8599@ism780c.UUCP> <1866@bsu-cs.UUCP>
Reply-To: zeilenga@hc.dspo.gov (Kurt Zeilenga)
Organization: U. of New Mexico, Albuquerque
Lines: 39

In article <1866@bsu-cs.UUCP> dhesi@bsu-cs.UUCP (Rahul Dhesi) writes:
>I respectfully suggest that the comma operator be used only where it is
>essential, and not for convenience.
>
>Why?  Because of the following strange situation.  The comma operator
>is one of the features of C that is used only rarely, the only common
>usages being in for loop expressions and in macros.  For this reason

I commonly use the comma operator in many other "peculiar" places (in
expression by passed to functions, loops, if statements, etc.) because
of convenience or need.  If C didn't have these convenieces, I would
us another language.

>compiler writers may not test it as exhaustively as they might, for
>example, test assignments or arithmetic operators.

The comma operator is as important as any other operator in C.  Should
we restrict the use of "=" because compiler writers may not test it
exhaustively.  It is the compilers writers job to implement the language
to spec (K&R, ANSI, or whatever).  If they can't handle it, then they
should find a new job.

>So it is more likely that your code will break because of a
>compiler bug if you use comma operators in peculiar situations.

Any peculiar situation is more likely to bring out a compiler
bug.  But suggesting programmers use less convenent operators is
not the solution.   What is the solution?  Better compilers (and
compiler writers :-).

>I base this statistical conclusion on just one line of C code that I
>wrote, that annoyed several C compilers on different flavors of UNIX.
>-- 
>Rahul Dhesi         UUCP:  <backbones>!{iuvax,pur-ee,uunet}!bsu-cs!dhesi

I base my conclusions on absolutely no statistics, just common sense.

-- 
	Kurt (zeilenga@hc.dspo.gov)