Introduce an export framework

The idea is to implement a framework which deal with everything (export an entry point in the UI, execute the document, etc.) except actually serializing the package (XAR, LaTeX, etc.) which will be done by one of the found Output Filters.

That way you just have to provide a "myformat" Output Filter and you automatically get a button in the export menu to export any page in your format (probably with the restriction that your Output Filter must implement WikiDocumentFilter interface to be sure you know about documents ).