Path: utzoo!attcan!uunet!wuarchive!psuvax1!news
From: flee@guardian.cs.psu.edu (Felix Lee)
Newsgroups: comp.lang.perl
Subject: Re: Is ; a simple statement?
Message-ID: <Ft?u$n_@cs.psu.edu>
Date: 9 Jul 90 06:18:25 GMT
References: <120@array.UUCP>
Sender: news@cs.psu.edu (Usenet)
Organization: Penn State Computer Science
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I thought about it a bit and decided that perl doesn't have null
expressions.  Consider the following:
	sub foo { 3; ; }
	print &foo;

If perl had null expressions, then I'd expect &foo to return an
undefined value, but instead it returns 3.

So I stared at perl's yacc file a bit, and lo, there is no such thing
as a null expression.  The "null statement" is handled in the rule
that says a label can be followed by a semicolon:
	bar: ;
and the label is optional.

Adding general null expressions may make perl quite un-yaccable.  I
think it's enough that you can say
	0 while (EXPR);
or
	while (EXPR) {}
and even
	while BLOCK {}
--
Felix Lee	flee@cs.psu.edu