Control.Quiver.Enumerator

This library defines a set of functions that convert between the Quiver and Data.Enumerator paradigms. The conversion is bidirectional: an appropriately-typed stream processor can be converted into an Iteratee and back into a stream processor. In addition, a stream processor can be fed into an iteratee (or Step), resulting in Enumerator.

The library has been designed specifically for use with Snap, but I'm sure that many other interesting uses of it exist.

Documentation

fromStream :: Stream a -> Maybe [a]

Converts a Stream to an optional list.

toStream :: Maybe [a] -> Stream a

Converts an optional list to a Stream.

toSingletonStream :: Maybe a -> Stream a

Converts an optional value to a singleton Stream.

iterateeToConsumer :: Functor m => Iteratee a m r -> Q.Consumer () a m (Either SomeException (r, Maybe [a]))

Converts an Iteratee into a Q.Consumer.

stepToConsumer :: Functor m => Step a m r -> Q.Consumer () a m (Either SomeException (r, Maybe [a]))

Converts a Step into a Q.Consumer.

consumerToIteratee :: Monad m => Q.Consumer a a' m r -> Iteratee a' m r

Converts a Q.Consumer into an Iteratee.

processorToEnumerator :: Monad m => Q.P a a' b () m r1 -> Step b m r2 -> Iteratee a' m (r1, r2)

Feed the output of a stream processor to a Step, effectively converting it into an Enumerator, generalised slightly to allow distinct input and output types. The chunks of the input stream are fed into the stream processor one element at the time, and its output is fed to the iteratee one element per chunk.