On 09/04/12 23:49, Paolo Capriotti wrote:
I'm pleased to announce the release of version 0.1.0 of pipes-core, a library for efficient, safe and compositional IO, similar in scope to iteratee and conduits.
I have some issues with the function names used firstP :: Monad m => Pipe a b m r -> Pipe (Either a c) (Either b c) m r secondP :: Monad m => Pipe a b m r -> Pipe (Either c a) (Either c b) m r Why are firstP and secondP not called leftP and rightP? Those are the corresponding functions in Arrow. Similarly (***) should be called (+++). I also don't like `intersperse`, which does something completely different from its Data.List counterpart. intersperse :: Monad m => (a -> Bool) -> Pipe a (Maybe a) m r Data.List.intersperse :: a -> [a] -> [a] The documentation is also a bit misleading "Yield Nothing when an input satisfying the predicate is received." To me this suggests that could behave like some kind of filter, intersperse p = pipe $ \x -> if p x then Nothing else Just x A true intersperse analogue would be intersperse x = do y0 <- await yield y0 forever $ do y <- await yield x yield y The function you have defined is something like `yieldNothingBeforeMatching`. Do you have a use case for this function? Perhaps an interesting combinator would be -- | Run the first pipe until it yields a value, then run the second pipe until it yields, the the first pipe again, etc. alternate :: Pipe a b m r -> Pipe a b m r -> Pipe a b m r intersperse x = alternate idP (forever (yield x)) Although I have no idea if it is actually useful in practice. Twan