Currentlly you can write a new questiontype because types are now plugins, but you can't add it to the known qtypes in import/export formats.

Example: Joseph Rezeau regular expression questiontype is only a slight variation of the shortanswer qtype. So if you use Joseph's original idea of REPLACING shortanswer qtype, you are able to import/export questions in a lot of formats including GIFT and XML.

But if you ADD it as a new question type (We choose 'regexp' with Joseph as name for this qtype and the code is ready and working) you are not able to export/import any regexp questions !

This is unfortunate so I think the import/export code should be made expandable if we want new custom qtypes to be really popular.

Maybe as a first step if Moodle xml was modified it will be a good start, but maybe also designing a general way for formats to be expandable would be better ?

Gustav, can you forward this to Howard Miller ?