On Sat, Aug 21, 2010 at 23:14, Paulo Tanimoto
One question: enumFile has type
enumFile :: FilePath -> Enumerator SomeException ByteString IO b
and iterParser has type
iterParser :: Monad m => Parser a -> Iteratee ParseError ByteString m a
How do we use both together? Something in these lines won't type-check
E.run (E.enumFile "file" E.$$ (E.iterParser p))
because the error types are different.
Forgot to mention that -- use the "mapError" function from enumerator-0.2.1 thusly: http://ianen.org/haskell/enumerator/api-docs/Data-Enumerator.html#v%3AmapErr... -------------------------------------------------------------------------------- parser :: Parser Foo toExc :: Show a => a -> E.SomeException toExc = E.SomeException . E.ErrorCall . show main :: IO () main = do run (enumFile "parsetest.txt" $$ mapError toExc $$ iterParser parser) >>= print -------------------------------------------------------------------------------- You don't have to map to SomeException -- any type will do. For example, in a complex pipeline with real error handling at the other end, you might want a custom error type so you'll know at what stage the error occurred.