This library offers an abstraction similar in scope to iteratees/enumerators/enumeratees, but with different characteristics and naming conventions.
Difference with traditional iteratees:
-
Simpler semantics: There is only one data type (
Pipe
), two primitives (await
andyield
), and only one way to composePipe
s (>+>
). In fact, (>+>
) is just convenient syntax for the composition operator inCategory
. Most pipes can be implemented just using theMonad
instance and composition. -
Different naming conventions: Enumeratees are called
Pipe
s, Enumerators areProducer
s, and Iteratees areConsumer
s.Producer
s andConsumer
s are just type synonyms forPipe
s with either the input or output end closed. -
Pipes form a Category: that means that composition is associative, and that there is an identity
Pipe
. -
"Vertical" concatenation works on every
Pipe
: (>>
), concatenatesPipe
s. Since everything is aPipe
, you can use it to concatenateProducer
s,Consumer
s, and even intermediatePipe
stages. Vertical concatenation can be combined with composition to create elaborate combinators, without the need of executing pipes in "passes" or resuming partially executed pipes.
This library is based on the pipes package by Gabriel Gonzalez.