The idea of fixed join point

A fixed join point let developers to express some feature variability in a transparent manner.
Aspects can be hooked to fixed join points.

It uses the include directive of PHP:

// here is a fixed join point
@include("auth.php")
// if the aspect auth.php exists, it is executed, otherwise nothing fails

Well, the cool thing is just the @ directive of PHP, that catches the Warning, and the looseness of the include directive, which just throws a warning (and not an error).

There is an implicit semantics in the file name included. For instance, in the example above, the auth.php file may contains some authentification mechanisms.

Known aspects are:
authentification: @include("auth.php") (an implementation is simplephpauth)
logging: @include("log.php") (an implementation is phpmodlog)
live debugging: @include("edit.php") (an implementation is livemaintenance)