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Path: utzoo!utcsri!greg
From: greg@utcsri.UUCP (Gregory Smith)
Newsgroups: net.lang
Subject: Re: Re: Multiple assignments
Message-ID: <2846@utcsri.UUCP>
Date: Mon, 26-May-86 16:08:51 EDT
Article-I.D.: utcsri.2846
Posted: Mon May 26 16:08:51 1986
Date-Received: Mon, 26-May-86 16:24:52 EDT
References: <1455@mmintl.UUCP> <825@bentley.UUCP> <1482@mmintl.UUCP> <201@cdx39.UUCP>
Reply-To: greg@utcsri.UUCP (Gregory Smith)
Organization: CSRI, University of Toronto
Lines: 32
Summary: 

In article <201@cdx39.UUCP> jc@cdx39.UUCP (John Chambers) writes:
>Surely there is no problem making a compiler understand
>such syntax.  As for why you might want it in C, haven't
>you ever been bitten by the "feature" of incompatible 
>types in a set-several-things-to-zero command?  Try the
>following:
>	main() {
>		char  *x;
>		double y;
>		y = x = 0;
>	}
>and see what your C compiler does.  Silly, isn't it?
>
It becomes the same as
	x = 0;
	y = x;	/* actually y=(double)x */

Are you suggesting that given (x,y)=0; it will be easier for a compiler
to detect the incompatibility and generate
	x = 0;
	y = 0.0;	????
I don't really think so. Note that the written-out 'explicit' version of your
initialization is as above; y = 0 causes an implicit ( compile-time )
conversion. So writing x=y=0; is asking for trouble, anyway. Actually,
this is the case with most compilers regardless of the types of x and y,
although it shouldn't be. Changing the syntax of multiple assignments
has little bearing on the problem itself, which is one of code generation.

-- 
"We demand rigidly defined areas of doubt and uncertainty!" - Vroomfondel
----------------------------------------------------------------------
Greg Smith     University of Toronto      UUCP: ..utzoo!utcsri!greg