PHP 5 is very very flexible in accessing member variables and member functions. These access methods maybe look unusual and unnecessary at first glance; but they are very useful sometimes; specially when you work with SimpleXML classes and objects. I have posted a similar comment in SimpleXML function reference section, but this one is more comprehensive.
I use the following class as reference for all examples:
<?php
class Foo {
public $aMemberVar = 'aMemberVar Member Variable';
public $aFuncName = 'aMemberFunc';
function aMemberFunc() {
print 'Inside `aMemberFunc()`';
}
}
$foo = new Foo;
?>
You can access member variables in an object using another variable as name:
<?php
$element = 'aMemberVar';
print $foo->$element; ?>
or use functions:
<?php
function getVarName()
{ return 'aMemberVar'; }
print $foo->{getVarName()}; ?>
Important Note: You must surround function name with { and } or PHP would think you are calling a member function of object "foo".
you can use a constant or literal as well:
<?php
define(MY_CONSTANT, 'aMemberVar');
print $foo->{MY_CONSTANT}; print $foo->{'aMemberVar'}; ?>
You can use members of other objects as well:
<?php
print $foo->{$otherObj->var};
print $foo->{$otherObj->func()};
?>
You can use mathods above to access member functions as well:
<?php
print $foo->{'aMemberFunc'}(); print $foo->{$foo->aFuncName}(); ?>