[plt-scheme] Enumeration types

Hi all,

Is it possible to create a enumeration type in scheme? Just like
enums in C? Or a way to emulate the workings?

I though about:
(define ENUM1 1)
(define ENUM2 2)
...
(define ENUMn n)

but this is dirty... is there a cleaner way?

Best regards,

-- 
Paulo J. Matos : pocm(_at_)rnl.ist.utl.pt
Instituto Superior Tecnico - Lisbon    
Software & Computer Engineering - A.I.
 - > http://www.rnl.ist.utl.pt/~pocm 
 ---	
	Yes, God had a deadline...
		So, He wrote it all in Lisp!