It's not OK and it's an artifact of the weak-typing and ill-defined semantics that pervade iteratee libraries. It's possible to do a lot of bad stuff, including binding with an iteratee yielding a remainder without consuming input. Regards, John A. De Goes Twitter: @jdegoes LinkedIn: http://linkedin.com/in/jdegoes On Apr 19, 2011, at 6:27 AM, Daniel Schüssler wrote:
Hello,
for reference, said instance is:
instance Monad m => Monad (Iteratee a m) where return x = yield x (Chunks [])
m0 >>= f = ($ m0) $ fix $ \bind m -> Iteratee $ runIteratee m >>= \r1 -> case r1 of Continue k -> return (Continue (bind . k)) Error err -> return (Error err) Yield x (Chunks []) -> runIteratee (f x) Yield x extra -> runIteratee (f x) >>= \r2 -> case r2 of Continue k -> runIteratee (k extra) Error err -> return (Error err) Yield x' _ -> return (Yield x' extra)
The thing I don't understand yet is the last line: Why is it OK to discard the leftover input from the (f x) Iteratee and yield just the leftover input from the first one (m0)?
Cheers, Daniel
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