Was this change reverted? from Zend/ChangeLog:
2003-06-09 Stanislav Malyshev <stas@zend.com>
* zend_API.c
zend_execute_API.c:
Support 'self' and 'parent' in call_user_func()
Using either 'self' or 'parent' now gives a warning, 'First argument
is expected to be a valid callback'. This worked as of the second
beta of PHP5, for example.
