Richard Stallman wrote:
> You have the right idea.

I have tried to finish the code too now ;-)

Please see the attached files. Beside a more complete widget type for 
colors I have also included some basic functions for testing custom 
types. I believe these could be useful.

I have tried to make them as clean and simple as they can be at the 
moment. However I am unsure about how to call the :match and :validate 
functions. I might very well be missing something concerning the 
conversion from and to external values.

BTW when I have been looking at this I have had a hard time to 
understand why there are both :match and :validate functions.

I also do not understand the paramters they take. Why do the :match 
function have a widget parameter? Does it have something to do with 
external - internal conversion, or?