
11 Apr
2009
11 Apr
'09
6:44 p.m.
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")
<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