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From: thomasm@llama.ingres.com (Tom Markson)
Newsgroups: comp.compilers
Subject: Semicolons (Re: Low-Rent Syntax)
Keywords: C, design, debug
Message-ID: <9008202341.AA06543@llama.ingres.com>
Date: 22 Aug 90 05:18:29 GMT
Sender: compilers-sender@esegue.segue.boston.ma.us
Reply-To: thomasm@llama.ingres.com (Tom Markson)
Organization: Compilers Central
Lines: 64
Approved: compilers@esegue.segue.boston.ma.us

> Well, I'll admit it :-).  I've been programming in C professionally for
> about 5 years, and about 1/2 my extra trips into the editor are still to
> correct missing semicolons.  I almost never *add* semicolons, though.
> This is true of most C programmers I know.  And note that when the added
> semicolon does appear, it usually takes the insidious form

> 	x = 100;
>	while( x );/* a nasty case */
>	/* 
>
>	 * these comments are intended only to obscure the fact
>	 * that the next statement will never be executed...
>
>	 */
>		x--;


The real problem here is not with the semicolon, it is with the grammar 
production that dominates C and Pascal:

while:	WHILE (expr) statement
	;

statement: '{' statements '}'
	 | while ';'
	 | /* etc */
	 ;

Thus, If WHILE were terminated with ENDWHILE, This error would not occur:

while:  WHILE (expr) 
		statements ';' 

	ENDWHILE ';'
	;

statements: statements ';' statement
	  | statement
	  ;


The semicolon in the erroneous code example above would simply be an empty 
statement.

> I'm just plain tired of debugging code (of my own and others' :-) like
>
>	if( v )
>		w;
>		if( x )
>			y;
>	else /*XXX*/;
>		z;

Again, this is the same problem as above.  As John mentioned, one safe
way to do it in C is to ALWAYS use braces after an if,for, etc..  You'll
find it makes your life much easier.

-- 
Tom Markson					Unix Systems
email: thomasm@llama.rtech.com			Ingres Corp
phone: 415-748-250
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