downloads | documentation | faq | getting help | mailing lists | reporting bugs | php.net sites | links | my php.net 
search for in the  

<Returning valuesInternal (built-in) functions>
Last updated: Thu, 26 Jun 2008

Variable functions

PHP supports the concept of variable functions. This means that if a variable name has parentheses appended to it, PHP will look for a function with the same name as whatever the variable evaluates to, and will attempt to execute it. Among other things, this can be used to implement callbacks, function tables, and so forth.

Variable functions won't work with language constructs such as echo(), print(), unset(), isset(), empty(), include(), require() and the like. Utilize wrapper functions to make use of any of these constructs as variable functions.

Example #1 Variable function example

<?php
function foo() {
   echo
"In foo()<br />\n";
}

function
bar($arg = '')
{
   echo
"In bar(); argument was '$arg'.<br />\n";
}

// This is a wrapper function around echo
function echoit($string)
{
   echo
$string;
}

$func = 'foo';
$func();        // This calls foo()

$func = 'bar';
$func('test');  // This calls bar()

$func = 'echoit';
$func('test');  // This calls echoit()
?>

An object method can also be called with the variable functions syntax.

Example #2 Variable method example

<?php
class Foo
{
   function
Variable()
   {
      
$name = 'Bar';
      
$this->$name(); // This calls the Bar() method
  
}
  
   function
Bar()
   {
       echo
"This is Bar";
   }
}

$foo = new Foo();
$funcname = "Variable";
$foo->$funcname();  // This calls $foo->Variable()

?>

See also call_user_func(), variable variables and function_exists().



add a noteadd a note User Contributed Notes
Variable functions
There are no user contributed notes for this page.




<Returning valuesInternal (built-in) functions>
Last updated: Thu, 26 Jun 2008
show source | credits | sitemap | contact | advertising | mirror sites
Copyright © 2001-2005 The PHP Group
All rights reserved.
This unofficial mirror is operated at: http://phpbuilder.com/
Last updated: Tue Nov 1 20:20:59 2005 EST
Columns / Articles | Tips / Quickies | News | News Linking and RSS Feeds | Shared Code Library
Mail Archives | Support / Discussion Forums | Get Started! Links | Contribute! | Docs