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Path: utzoo!linus!vaxine!wjh12!kendall
From: kendall@wjh12.UUCP (Sam Kendall)
Newsgroups: net.lang.c
Subject: Re: Must useless expressions be evaluated?
Message-ID: <334@wjh12.UUCP>
Date: Sat, 15-Oct-83 04:52:56 EDT
Article-I.D.: wjh12.334
Posted: Sat Oct 15 04:52:56 1983
Date-Received: Sun, 16-Oct-83 14:31:56 EDT
References: <187@bbncca.ARPA>, <317@ucbtopaz.CC.Berkeley.ARPA>
Organization: Delft Consulting Corp., New York
Lines: 18


                I think useless expressions must be evaluated, simply because
        there is no syntactic criterion to determine the uselessness of any
        expression.  For example,
		(i=j)+something()+k++;
	is not syntactically different from
		(i=j)+1+k++;
	but something() probably has side effects.

Well, `something()' is a function call, and `1' isn't.

Some (syntactic) operators may have side effects, and others never do.  If
the result of one of the former isn't used, it must still be evaluated.  If
the result of one of the latter isn't used, there is no reason to evaluate
it.  Please, let's drop this topic.

	Sam Kendall		  {allegra,ihnp4}!wjh12!kendall
	Delft Consulting Corp.	    decvax!genrad!wjh12!kendall