This guide is based on the PHP4 Manual, available at http://www.php.net/docs.php .
The only classifier in PHP4 is 'Class'.
PHP4 Class can not participate in an Association.
There is no Exception in PHP4
There are two files generated for each Class generation process:
'.inc' file that contains the class declaration
'.php' file that includes related the '.inc' on its first line
The following tagged value keys are supported for PHP4 Class:
'<<<' for Heredoc string
'initval' for an initial value of an operation parameter
'&' for operation parameter passed by reference
'&' for a function that returns a reference