Just to clarify, I really liked the SYB solution to my previous issue
with stripping token locations. It looked like this:
strip :: (Data a) => a -> a
strip = everywhere (mkT f)
where f (TokenPos a _) = a
f x = x
In the general AST transformation case, my constructor name is the
same and so is the number of arguments. So, yes, it's a different
type but it's a derivative of Data and Typeable just like the
original type.
Conceptually, I want to "lookup" the new type from a given module,
using the same constructor name as the original type. Then I want to
apply morph to every argument of the source constructor and give the
resulting values to the new constructor.
Lastly, I would like to write pattern matches for special cases (see
TokenPos above) and write out the transformation by hand. My ASTs are
quite large and there aren't that many special cases.
Thanks, Joel
On Apr 19, 2007, at 5:11 PM, Joel Reymont wrote:
instance Morpher Type C.Type where
...
morph (TyList ty) = liftM C.TyList (morph ty)
morph (TyArray ty) = liftM C.TyArray (morph ty)
morph (TySeries ty) = liftM C.TySeries (morph ty)
morph (TyInput ty) = liftM C.TyProp (morph ty)
morph (TyRef ty) = liftM C.TyRef (morph ty)
morph TyUnit = return C.TyUnit
morph TyPrintDest = return C.TyPrintDest
--
http://wagerlabs.com/
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