resumable-exceptions-0.0.0.20100313: A monad transformer for resumable exceptions Source code Contents Index

Control.Monad.Resumable Portability non-portable (GHC extensions) Stability experimental Maintainer nicolas.frisby@gmail.com

Contents Monadic interface Monad transformer Run functions Scope manipulation Manipulating the inner monad

Description

A monad transformer for resumable exceptions. The ResumableT transformer is isomorphic to ReactT, the dominant reactivity monad in the literature. The differences serve to match the mtl style.

Synopsis

class Monad m => MonadResumable req res m | m -> req res where yield :: req -> (res -> m a) -> m a handle :: m a -> (req -> (res -> m a) -> m a) -> m a type Resumable scope req res = ResumableT scope req res Identity newtype ResumableT scope req res m a = ResumableT { unResumableT :: m (Either (req, res -> ResumableT scope req res m a) a) } runResumableT :: Monad m => ResumableT scope req res m a -> m (req -> (res -> ResumableT scope req res m a) -> ResumableT scope req res m a) -> m a runResumableT_responder :: Monad m => ResumableT scope req res m a -> m (req -> ResumableT scope req res m res) -> m a runResumableT' :: Monad m => ResumableT scope req res m a -> (req -> (res -> ResumableT scope req res m a) -> ResumableT scope req res m a) -> m a runResumableT_responder' :: Monad m => ResumableT scope req res m a -> (req -> ResumableT scope req res m res) -> m a data Static data Dynamic asStatic :: ResumableT Static req res m a -> ResumableT Static req res m a asDynamic :: ResumableT Dynamic req res m a -> ResumableT Dynamic req res m a statically :: Scoped Static m => (ScopedAs Static m a -> ScopedAs Static m b) -> m a -> m b dynamically :: Scoped Dynamic m => (ScopedAs Dynamic m a -> ScopedAs Dynamic m b) -> m a -> m b mapResumableT_static :: (m (Either (req, res -> ResumableT scope req res m a) a) -> n (Either (req', res' -> ResumableT scope' req' res' n b) b)) -> ResumableT scope req res m a -> ResumableT scope' req' res' n b mapResumableT_dynamic :: (Monad m, Monad n) => (m (Either (req, res -> ResumableT scope req res m a) a) -> n (Either (req, res -> ResumableT scope req res m a) b)) -> ResumableT scope req res m a -> ResumableT scope req res n b

Monadic interface

class Monad m => MonadResumable req res m | m -> req res where Source

A monadic interface for resumable exceptions. Methods yield :: req -> (res -> m a) -> m a Source Raise the exception: a request and a resumption to use if the request can be handled. handle :: m a -> (req -> (res -> m a) -> m a) -> m a Source Installs a handler to quiesce an exception before it percolates to the higher-level handlers. Instances MonadResumable req res m => MonadResumable req res (ContT r m) (Error e, MonadResumable req res m) => MonadResumable req res (ErrorT e m) MonadResumable req res m => MonadResumable req res (StateT s m) (Monoid w, MonadResumable req res m) => MonadResumable req res (WriterT w m) MonadResumable req res m => MonadResumable req res (ReaderT r m) (Monoid w, MonadResumable req res m) => MonadResumable req res (RWST r w s m) Monad m => MonadResumable req res (ResumableT Dynamic req res m) Monad m => MonadResumable req res (ResumableT Static req res m)

Monad transformer

type Resumable scope req res = ResumableT scope req res Identity Source

newtype ResumableT scope req res m a Source

Constructors ResumableT unResumableT :: m (Either (req, res -> ResumableT scope req res m a) a) Instances (Monoid w, MonadReader r m, MonadState s m, MonadWriter w m) => MonadRWS r w s (ResumableT Dynamic req res m) (Monoid w, MonadReader r m, MonadState s m, MonadWriter w m) => MonadRWS r w s (ResumableT Static req res m) Monad m => MonadResumable req res (ResumableT Dynamic req res m) Monad m => MonadResumable req res (ResumableT Static req res m) MonadReader r m => MonadReader r (ResumableT Dynamic req res m) MonadReader r m => MonadReader r (ResumableT Static req res m) MonadState s m => MonadState s (ResumableT scope req res m) MonadError e m => MonadError e (ResumableT Dynamic req res m) MonadError e m => MonadError e (ResumableT Static req res m) MonadWriter w m => MonadWriter w (ResumableT scope req res m) Scoped scope (ResumableT scope' req res m) MonadTrans (ResumableT scope req res) Monad m => Monad (ResumableT scope req res m) Functor m => Functor (ResumableT scope req res m) MonadFix m => MonadFix (ResumableT scope req res m) MonadCont m => MonadCont (ResumableT scope req res m) MonadIO m => MonadIO (ResumableT scope req res m)

Run functions

runResumableT :: Monad m => ResumableT scope req res m a -> m (req -> (res -> ResumableT scope req res m a) -> ResumableT scope req res m a) -> m a Source

The preferred top-level interface nevers allows exceptions to go unhandled.

runResumableT_responder :: Monad m => ResumableT scope req res m a -> m (req -> ResumableT scope req res m res) -> m a Source

This variation recognizes that the handling of requests primarily involves generating responses.

runResumableT' :: Monad m => ResumableT scope req res m a -> (req -> (res -> ResumableT scope req res m a) -> ResumableT scope req res m a) -> m a Source

The handler does not depend on the inner monad.

runResumableT_responder' :: Monad m => ResumableT scope req res m a -> (req -> ResumableT scope req res m res) -> m a Source

The responder does not depend on the inner monad.

Scope manipulation

data Static Source

Instances (Monoid w, MonadReader r m, MonadState s m, MonadWriter w m) => MonadRWS r w s (ResumableT Static req res m) Monad m => MonadResumable req res (ResumableT Static req res m) MonadReader r m => MonadReader r (ResumableT Static req res m) MonadError e m => MonadError e (ResumableT Static req res m)

data Dynamic Source

Instances (Monoid w, MonadReader r m, MonadState s m, MonadWriter w m) => MonadRWS r w s (ResumableT Dynamic req res m) Monad m => MonadResumable req res (ResumableT Dynamic req res m) MonadReader r m => MonadReader r (ResumableT Dynamic req res m) MonadError e m => MonadError e (ResumableT Dynamic req res m)

asStatic :: ResumableT Static req res m a -> ResumableT Static req res m a Source

Establishes static scoping as default.

asDynamic :: ResumableT Dynamic req res m a -> ResumableT Dynamic req res m a Source

Establishes dynamic scoping as default.

statically :: Scoped Static m => (ScopedAs Static m a -> ScopedAs Static m b) -> m a -> m b Source

dynamically :: Scoped Dynamic m => (ScopedAs Dynamic m a -> ScopedAs Dynamic m b) -> m a -> m b Source

Manipulating the inner monad

mapResumableT_static :: (m (Either (req, res -> ResumableT scope req res m a) a) -> n (Either (req', res' -> ResumableT scope' req' res' n b) b)) -> ResumableT scope req res m a -> ResumableT scope' req' res' n b Source

This manipulation of the inner monad acheives static scoping -- the manipulation is not preserved in the resumption.

mapResumableT_dynamic :: (Monad m, Monad n) => (m (Either (req, res -> ResumableT scope req res m a) a) -> n (Either (req, res -> ResumableT scope req res m a) b)) -> ResumableT scope req res m a -> ResumableT scope req res n b Source

This manipulation of the inner monad acheives dynamic scoping -- the manipulation is preserved in the resumption.

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