An enumeration as a type: how to do it?

[tcklnbrg]

Well, I guess, I am going to go for it and try to write my java code
generator in Mercury. 
I hope you will all put up with my questions while I get started:

How do I do an enumerated type?  Something like in standard Prolog:

integraltype(T):- member(T, ['byte', 'short', 'int', 'long', 'char']).

%I need for byte, short, int, long, char, etc to be strings not Mercury
%datatypes.

All help greatly appreciated,

Thanks,

Ann Tecklenburg