
PXP::ExtensionPointClass - Basic logic and Mandatory interfaces for L<PXP::ExtensionPoint>s.

use base qw(PXP::ExtensionPointClass);
...
# overload basic methods
sub register {
}

The PXP::ExtensionPointClass helps implement new ExtensionPoints. It provides basic methods and logic for dealing with Extensions.
The register method is called by Extensions to add themselves to the extension directory maintained by the ExtensionPoint.
An ExtensionPoint must overload this method, use its own data structure and check that only valid extensions try to register.
Return 'undef' if the extension is invalid.
Return the extension itself if it has been successfully added to the internal registry.