[Haskell-beginners] How does the Deriving being implemented in Haskell?

Haisheng Wu freizl at gmail.com
Tue Jun 14 14:07:27 CEST 2011


Hi guys,
  What I understanding `deriving` is Haskell automatically make a type to be
a instance of a particular typeclass.
  If that's the case, the question is How does Haskell do that underline?

  Take code below as sample, the type Day is now an instance of Bounded.

 data Day = Monday | Tuesday | Wednesday | Thursday | Friday | Saturday |
Sunday
            deriving (Bounded, Enum)

  Therefore, *minBound :: Day* will produce *Monday*.

 Just be curious how it is being implemented.

Thanks.
Simon
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.haskell.org/pipermail/beginners/attachments/20110614/2bffcfc2/attachment.htm>


More information about the Beginners mailing list