PHP supports the concept of variable functions. This means that if a variable name is followed by parentheses, PHP will look for a function with the same name as the value of the variable and try to execute it. Variable functions can be used to implement some uses including callback functions, function tables, and so on.
Variable functions cannot be used for language structures, For example, Echo (), print (), unset (), Isset (), empty (), include (), require (), and similar statements。 You need to use your own wrapper functions for using these structures as variable functions.
Example #1 Variable Function example
Copy Code code as follows:
<?php
function foo () {
echo "in foo () <br/>/n";
}
function bar ($arg = ') {
echo "in Bar" (); Argument was ' $arg '. <br/>/n ";
}
Wrapping functions that use echo
function Echoit ($string)
{
Echo $string;
}
$func = ' Foo ';
$func (); This calls Foo ()
$func = ' Bar ';
$func (' Test '); This calls bar ()
$func = ' Echoit ';
$func (' Test '); This calls Echoit ()
?>
You can also invoke the method of an object by using the attributes of a variable function.
Example #2 variable method paradigm
Copy Code code as follows:
<?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 ()
?>
