All the info that is showed in the class browser is generated by a program called cTags. It parses your source files to some sort of tag based file wich is read by the class viewer, which in turn will render your program structure out of it.
This works fine for quite alot of langs because support has been baked in to cTags for those (Java, C(++), eiffel, vera). Support for scripting langs is quite limited unless you write it yourself. There are some good site about how to write parsers using cTags. And the structure of a tag file, most of it is available at cTags and you can always google.