Path: utzoo!utgpu!water!watmath!clyde!rutgers!cmcl2!husc6!bbn!uwmcsd1!ig!agate!ucbvax!hplabs!sdcrdcf!csun!csuna!aeusesef
From: aeusesef@csuna.UUCP (sean fagan)
Newsgroups: comp.lang.c
Subject: Re: New Features:  ++(expr)
Keywords: lvalue expression enough already!
Message-ID: <1059@csuna.UUCP>
Date: 14 Feb 88 21:50:15 GMT
References: <386@osupyr.UUCP> <1102@bc-cis.UUCP> <681@devon.UUCP>
Reply-To: aeusesef@csuna.UUCP (Sean Eric Fagan)
Organization: California State University, Northridge
Lines: 38

In article <681@devon.UUCP> paul@devon.UUCP (Paul Sutcliffe Jr.) writes:
>In article <1102@bc-cis.UUCP> john@bc-cis.UUCP (John L. Wynstra) writes:
>> In article <386@osupyr.UUCP> ddc@osupyr.UUCP (Don Comeau) writes:
>> > Since everyone else is suggesting their addition to C, here is one I
>> > think would be useful.  Why are ++ and -- still limited to lvalues?  I
>> > think ++expresion should be an expression which has the value
>> > expression+1.
They are limited to lvalues because ++ and -- are, respectively,
incrementors and decrementors.  It makes no sense to increment an expression
(you can increment the value of it, but not the expression itself), whereas
incrementing an lvalue makes perfect sense.
[++lvalue is redundant]
>	lvalue = lvalue + 1
>	lvalue += 1
yeah, but then you have something like
    val = .... lvalue++ .... lvalue++ .... lvalue++;
(they are, hopefully, different lvalues, but not necessarily)
Your way, you have to do
    val = .... (lvalue += 1) .... (lvalue += 1) .... (lvalue += 1);
Hmm.. I think I'd take the ++ operators.  Now, if we use ++(expr), we get
    val = .... ++(a+b+c) ... ++(a+b+c) ... ++(a+b+c);
or
    val = .... (a+b+c+1) ... (a+b+c+1) ... (a+b+c+1);
Same amount of typing (but less shifting on my keyboard).  The only reason I
could see having the '++(expr)' is so that the '1' added would be multiplied
by the size of the expression.  However, I've never had a need to do that,
and overloading this operator in such a foolish fashion is, well, foolish.

>Paul Sutcliffe, Jr.
>UUCP (smart):  paul@devon.UUCP

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