On Sat, Apr 11, 2009 at 20:44, Anatoly Yakovenko <aeyakovenko@gmail.com> wrote:

i am trying to understand how data.data works. How would i traverse
the subterms of one type and build another type out of them.
something like this:

> gmapQ (\a -> Right a) (Just "hello")

I am not sure I understand what you're trying to do here. However, in general, 'gmapQ' is used in combination with 'mkQ' or 'extQ'. Those are not in Data.Data: you can import Data.Generics to get everything syb-related.

Cheers,
Pedro

<interactive>:1:0:
Inferred type is less polymorphic than expected
Quantified type variable `d' escapes
In the first argument of `gmapQ', namely `(\ a -> Right a)'
In the expression: gmapQ (\ a -> Right a) (Just "hello")
In the definition of `it':
it = gmapQ (\ a -> Right a) (Just "hello")

Thanks,
Anatoly
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