Compatability with various different PHP versions

PHP5 changes the way the world revolves... well, it changes the way objects are handled so that $object is always a reference to an object. The consequence is that in PHP5, this: $object = new Foo(); $copy = $object; is equivalent to $object = new Foo(); $copy = &$object; in PHP4. In PHP5, the = operator is copy by reference not copy by value.

Conveniently, PHP5 provides you with the clone keyword to get around this. Inconveniently, that same keyword is not in PHP4 so you can't just use it to get around your problems.

If the version of PHP being used here is earlier than 5.0, then use a PHP-only inplementation of the clone keyword (as a function) from the PEAR PHP_Compat library:

http://pear.php.net/package/PHP_Compat

So now, instead of using the above construct to copy the $object, you use: $object = new Foo(); $copy = clone($object);

Note that in normal PHP5, you would not include the parentheses as clone is a keyword not a function, but for the PHP4 compatability to work, it has to be written as a function. PHP5 will just throw away the parentheses, pretending that they are for (an unneeded) grouping not a function call.

• filesource: Source Code for this file
• version: $Id$
• license: GNU Public License
• copyright: Copyright Stuart Prescott
• author: Stuart Prescott