In a suggestion to the XML Schema Working Group, Axel Dahmen suggested defining a facet that allows the introduction of new lexical forms for existing data types. This would allow you, for example, to write a decimal value as "1,23", or a date as "12DEC2008", or a boolean as "yes". The Schema WG has already put out two "last call" drafts of the XSD 1.1 spec, so it's not really welcoming ideas for new features at the moment, but I thought I would take a look at this one independently...   more »