Path: utzoo!utgpu!water!watmath!clyde!bellcore!faline!ulysses!allegra!princeton!udel!gatech!mcnc!decvax!decwrl!pyramid!prls!philabs!pwa-b!mmintl!franka
From: franka@mmintl.UUCP
Newsgroups: comp.lang.c
Subject: Re: == vs =
Message-ID: <2681@mmintl.UUCP>
Date: 23 Jan 88 00:24:45 GMT
References: <626@PT.CS.CMU.EDU> <214@oink.UUCP>
Reply-To: franka@mmintl.UUCP (Frank Adams)
Organization: Multimate International, E. Hartford, CT.
Lines: 31
Posted: Fri Jan 22 19:24:45 1988

In article <214@oink.UUCP> jep@oink.UUCP (James E. Prior) writes:
>In article <626@PT.CS.CMU.EDU> edw@IUS1.CS.CMU.EDU (Eddie Wyatt) writes:
>>The language D should redefine assignment to := then hopefully this type
>>of bug will go away. (ie. we should learn from our mistakes)
>
>Like the authors of C, I find it most important to preserve a single
>character operator for assignment.
>I find := for assignment to be quite obnoxious.  It's the worst choice
>I've ever seen.

Given the chance to redefine things, I would keep == for comparison exactly
as it is.  I would also keep = as it is *for the most common kind of
comparsion* -- one where the result is not used.  I would then introduce a
new operator, perhaps :=, for the relatively rare assignment where the
result is used.

In other words, the type of an expression whose main operator is = is void.
This lets us adopt a strict rule that not using an expression whose type is
void is an error, without taking anything away from the programmer.

(There is something to be said for dropping the := as defined above, so that
instead of writing, for example, while ((ch = getchar()) != EOF) ... one
would write while ((ch = getchar(), ch) != EOF) ....  This gets a little
uglier when the expression being assigned into is not a simple variable
name, but still not so bad as all that.  It will probably lead people to
write x = 0; y = 0; instead of a single statement; but this strikes me as a
minor point.)
-- 

Frank Adams                           ihnp4!philabs!pwa-b!mmintl!franka
Ashton-Tate          52 Oakland Ave North         E. Hartford, CT 06108