Path: utzoo!utgpu!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!rutgers!bellcore!texbell!sugar!ficc!peter
From: peter@ficc.uu.net (Peter da Silva)
Newsgroups: comp.lang.c
Subject: Re: new do-while syntax
Message-ID: <2507@ficc.uu.net>
Date: 20 Dec 88 15:43:09 GMT
References: <3049@arcturus> <864@calvin.EE.CORNELL.EDU> <1716@buengc.BU.EDU> <8562@alice.UUCP>
Organization: SCADA
Lines: 33

In article <8562@alice.UUCP>, ark@alice.UUCP (Andrew Koenig) writes:
> As I said before, it's way too late to get anything like this
> into C now.  It's fun to think about, though.

Is it? Petition your compiler writer. It should be a completely safe and
transparent extension to the existing syntax. The following should all
be valid:

	do ... while(x);	/* existing do/while, null while expr */
	while(x) ...		/* existing while, null do expr */
	do ... while(x) ...	/* full do/while */

The yaccoid BNF would be (since ";" is a valid statement):

dowhile	:	do WHILE(expr) statement
	;

do	:	/* nothing */
	|	DO statement
	;

If you can get a few compiler writers to put this in, it'll have a chance
of making it to the next version of 'C'. It reduces the complexity of the
language, too... replaces three constructs (do, while, and for) with one.
(yes, I am aware of the 'continue' problem, and I'm not suggesting removing
the for statement).

In fact, this could be declared an "editorial change" if you have the
brass.
-- 
Peter da Silva, Xenix Support, Ferranti International Controls Corporation.
Work: uunet.uu.net!ficc!peter, peter@ficc.uu.net, +1 713 274 5180.
Home: bigtex!texbell!sugar!peter, peter@sugar.uu.net.