Hello.
Is there any Haskell implementation that supports
extensible data types, in which new value constructors
can be added to a previously declared data type,
like
data Fn = Sum | Pro | Pow
...
extend data Fn = Sin | Cos | Tan
where first the Fn datatype had only three values,
(Sum, Pro and Pow) but later it was extended with
three new values (Sin, Cos and Tan)?
What are the pointers to documentation on such
kind of extensions to Haskell?
Thanks.
Romildo
--
Prof. José Romildo Malaquias <[EMAIL PROTECTED]>
Departamento de Computação
Universidade Federal de Ouro Preto
Brasil
