Embedding Perl in HTML with Mason

Chapter 12. Custom Mason Subclasses

Something that we have tried very hard to do beginning with the 1.10 release of Mason is to make it easier to customize Mason’s behavior. Jon Swartz was already on this track even back with the release of 0.80, which saw the first appearance of the HTML::Mason::Resolver classes, but 1.10 tries to bring this to new levels.

Starting with 1.10 it has become possible to subclass almost every core class that comes with Mason. Some obvious candidates for subclassing include the Lexer, Compiler, and Resolver. This chapter will demonstrate how you might go about implementing subclasses of various Mason objects.

Class::Container as a Superclass

A number of modules in Mason are subclasses of Class::Container. This is a class that was created to encapsulate some common behaviors for Mason objects. Originally, it was called HTML::Mason::Container, but Ken Williams decided to package this class separately and release it to CPAN, as it solves some fundamental problems of a large object-oriented system. Any Mason object that takes parameters to its constructor must inherit from this module. Of course, since all of the classes that you might consider subclassing inherit from Class::Container already, you shouldn’t need to inherit from it directly. However, you may need to use some of its methods. We will briefly cover a few of them here, but see the Class::Container documentation for more details.

The modules in the Mason core distribution that are Class::Container ...