RE: [PHP] variable functions: empty/isset/unset invalid?

Thanks for the additional code, now I see what you are after. Sorry, I don't know the answer, other than using curly braces will fix the problem for empty(). Also, a User Contributed Note at http://www.php.net/manual/en/functions.php#functions.user-defined has this to say: <quote> there are tons of good uses for this sort of functionality. But it should be noted that this will not work with include() include_once() require() require_once() it's safe to assume that this is for safty. </quote> Kirk > -----Original Message----- > From: Philip Olson [mailto:philip@cornado.com] > Sent: Monday, May 07, 2001 11:45 AM > To: php-general@lists.php.net > Subject: RE: [PHP] variable functions: empty/isset/unset invalid? > > > > I wish it were that easy. Also, I'm looking for words on WHY this > behavior exists. > > http://www.php.net/manual/en/functions.variable-functions.php > > <?php > > // works > if (empty($var)) print '$var is empty<br>'; > > // works > $foo = 'is_string'; > $var = 'abcdef'; > if ($foo($var)) print '$var is a string<br>'; > > // works > $foo = 'strlen'; > $var = 'abcdef'; > if ($foo($var) > 5) print '$var is over 5 chars<br>'; > > // doesn't work : Fatal Error : Call to undefined function: empty() > // same with isset() and unset() > $foo = 'empty'; > if ($foo($var)) print '$var is empty'; > > ?> > > In otherwords, only these few functions aren't working as "variable > functions" but result in a "Fatal Error" instead. Why? > > > Regards, > Philip > > On Mon, 7 May 2001, Johnson, Kirk wrote: > > > Change the parens around $var to curly braces: > > > > if ($foo{$var}) print 'worked.'; > > > > Kirk