Copyright	(C) 2012 Edward Kmett
License	BSD-style (see the file LICENSE)
Maintainer	Edward Kmett <ekmett@gmail.com>
Stability	provisional
Portability	rank-2, GADTs
Safe Haskell	None
Language	Haskell2010

Data.Machine.Type

Contents

Machines
- Building machines from plans
- Deconstructing machines back into plans
Reshaping machines
Applicative Machines

Description

Synopsis

Machines

newtype MachineT m k o Source #

A MachineT reads from a number of inputs and may yield results before stopping with monadic side-effects.

Constructors

MachineT
Fields runMachineT :: m (Step k o (MachineT m k o))

Instances

Monad m => Functor (MachineT m k) Source #
Methods fmap :: (a -> b) -> MachineT m k a -> MachineT m k b # (<$) :: a -> MachineT m k b -> MachineT m k a #
(Monad m, Appliance k) => Applicative (MachineT m k) Source #
Methods pure :: a -> MachineT m k a # (<>) :: MachineT m k (a -> b) -> MachineT m k a -> MachineT m k b # (>) :: MachineT m k a -> MachineT m k b -> MachineT m k b # (<*) :: MachineT m k a -> MachineT m k b -> MachineT m k a #
(~) (* -> *) m Identity => Foldable (MachineT m k) Source #	This permits toList to be used on a Machine.
Methods fold :: Monoid m => MachineT m k m -> m # foldMap :: Monoid m => (a -> m) -> MachineT m k a -> m # foldr :: (a -> b -> b) -> b -> MachineT m k a -> b # foldr' :: (a -> b -> b) -> b -> MachineT m k a -> b # foldl :: (b -> a -> b) -> b -> MachineT m k a -> b # foldl' :: (b -> a -> b) -> b -> MachineT m k a -> b # foldr1 :: (a -> a -> a) -> MachineT m k a -> a # foldl1 :: (a -> a -> a) -> MachineT m k a -> a # toList :: MachineT m k a -> [a] # null :: MachineT m k a -> Bool # length :: MachineT m k a -> Int # elem :: Eq a => a -> MachineT m k a -> Bool # maximum :: Ord a => MachineT m k a -> a # minimum :: Ord a => MachineT m k a -> a # sum :: Num a => MachineT m k a -> a # product :: Num a => MachineT m k a -> a #
Monad m => Pointed (MachineT m k) Source #
Methods point :: a -> MachineT m k a #
Monad m => Semigroup (MachineT m k o) Source #
Methods (<>) :: MachineT m k o -> MachineT m k o -> MachineT m k o # sconcat :: NonEmpty (MachineT m k o) -> MachineT m k o # stimes :: Integral b => b -> MachineT m k o -> MachineT m k o #
Monad m => Monoid (MachineT m k o) Source #
Methods mempty :: MachineT m k o # mappend :: MachineT m k o -> MachineT m k o -> MachineT m k o # mconcat :: [MachineT m k o] -> MachineT m k o #

data Step k o r Source #

This is the base functor for a Machine or MachineT.

Note: A Machine is usually constructed from Plan, so it does not need to be CPS'd.

Constructors

Stop
Yield o r
Await (t -> r) (k t) r

Instances

Functor (Step k o) Source #
Methods fmap :: (a -> b) -> Step k o a -> Step k o b # (<$) :: a -> Step k o b -> Step k o a #

type Machine k o = forall m. Monad m => MachineT m k o Source #

A Machine reads from a number of inputs and may yield results before stopping.

A Machine can be used as a MachineT m for any Monad m.

runT_ :: Monad m => MachineT m k b -> m () Source #

Stop feeding input into model, taking only the effects.

runT :: Monad m => MachineT m k b -> m [b] Source #

Stop feeding input into model and extract an answer

run :: MachineT Identity k b -> [b] Source #

Run a pure machine and extract an answer.

runMachine :: MachineT Identity k o -> Step k o (MachineT Identity k o) Source #

runMachine = runIdentity . runMachineT

encased :: Monad m => Step k o (MachineT m k o) -> MachineT m k o Source #

Pack a Step of a Machine into a Machine.

Building machines from plans

construct :: Monad m => PlanT k o m a -> MachineT m k o Source #

Compile a machine to a model.

repeatedly :: Monad m => PlanT k o m a -> MachineT m k o Source #

Generates a model that runs a machine until it stops, then start it up again.

repeatedly m = construct (forever m)

unfoldPlan :: Monad m => s -> (s -> PlanT k o m s) -> MachineT m k o Source #

Unfold a stateful PlanT into a MachineT.

before :: Monad m => MachineT m k o -> PlanT k o m a -> MachineT m k o Source #

Evaluate a machine until it stops, and then yield answers according to the supplied model.

preplan :: Monad m => PlanT k o m (MachineT m k o) -> MachineT m k o Source #

Incorporate a Plan into the resulting machine.

Deconstructing machines back into plans

deconstruct :: Monad m => MachineT m k (Either a o) -> PlanT k o m a Source #

tagDone :: Monad m => (o -> Bool) -> MachineT m k o -> MachineT m k (Either o o) Source #

Use a predicate to mark a yielded value as the terminal value of this Machine. This is useful in combination with deconstruct to combine Plans.

finishWith :: Monad m => (o -> Maybe r) -> MachineT m k o -> MachineT m k (Either r o) Source #

Use a function to produce and mark a yielded value as the terminal value of a Machine. All yielded values for which the given function returns Nothing are yielded down the pipeline, but the first value for which the function returns a Just value will be returned by a Plan created via deconstruct.

Reshaping machines

fit :: Monad m => (forall a. k a -> k' a) -> MachineT m k o -> MachineT m k' o Source #

Connect different kinds of machines.

fit id = id

fitM :: (Monad m, Monad m') => (forall a. m a -> m' a) -> MachineT m k o -> MachineT m' k o Source #

pass :: k o -> Machine k o Source #

Given a handle, ignore all other inputs and just stream input from that handle.

pass id :: Process a a
pass L  :: Tee a b a
pass R  :: Tee a b b
pass X  :: Wye a b a
pass Y  :: Wye a b b
pass Z  :: Wye a b (Either a b)

starve :: Monad m => MachineT m k0 b -> MachineT m k b -> MachineT m k b Source #

Run a machine with no input until it stops, then behave as another machine.

stopped :: Machine k b Source #

This is a stopped Machine

stepMachine :: Monad m => MachineT m k o -> (Step k o (MachineT m k o) -> MachineT m k' o') -> MachineT m k' o' Source #

Transform a Machine by looking at a single step of that machine.

Applicative Machines

class Appliance k where Source #

An input type that supports merging requests from multiple machines.

Minimal complete definition

applied

Methods

applied :: Monad m => MachineT m k (a -> b) -> MachineT m k a -> MachineT m k b Source #