In Haskell, data types and contructors must be designated by names whose first letter is capitalised. So,
> data currency = ... is illegal. Instead use, > data Currency = Dollar Double | Pound Double | Zloty Double | Euro Double Above are four data constructors and they can be used to contruct a datum of the type Currency. They can be exploited in functions through pattern matching as follows, > toDollar :: Currency -> Currency > toDollar (Pound d) = Dollar ( d / 2 ) > toDollar (Euro d) = Dollar ( d / 1.01 ) > ... I think, to answer your last question, that they are functions, however they can only be defined using a much more limited syntax. I'm sure someone else can give a fuller answer here. Tom _______________________________________________ Haskell mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell
