transformers-0.6.1.0: Concrete functor and monad transformers
Copyright(c) Ross Paterson 2017
LicenseBSD-style (see the file LICENSE)
MaintainerR.Paterson@city.ac.uk
Stabilityexperimental
Portabilityportable
Safe HaskellSafe
LanguageHaskell2010

Control.Monad.Trans.Select

Description

Selection monad transformer, modelling search algorithms.

Synopsis

The Select monad

type Select r = SelectT r Identity Source #

Selection monad.

select :: ((a -> r) -> a) -> Select r a Source #

Constructor for computations in the selection monad.

runSelect :: Select r a -> (a -> r) -> a Source #

Runs a Select computation with a function for evaluating answers to select a particular answer. (The inverse of select.)

mapSelect :: (a -> a) -> Select r a -> Select r a Source #

Apply a function to transform the result of a selection computation.

The SelectT monad transformer

newtype SelectT r (m :: Type -> Type) a Source #

Selection monad transformer.

SelectT is not a functor on the category of monads, and many operations cannot be lifted through it.

Constructors

SelectT ((a -> m r) -> m a) 

Instances

Instances details
MonadTrans (SelectT r) Source # 
Instance details

Defined in Control.Monad.Trans.Select

Methods

lift :: Monad m => m a -> SelectT r m a Source #

MonadFail m => MonadFail (SelectT r m) Source # 
Instance details

Defined in Control.Monad.Trans.Select

Methods

fail :: String -> SelectT r m a Source #

MonadIO m => MonadIO (SelectT r m) Source # 
Instance details

Defined in Control.Monad.Trans.Select

Methods

liftIO :: IO a -> SelectT r m a Source #

(Functor m, MonadPlus m) => Alternative (SelectT r m) Source # 
Instance details

Defined in Control.Monad.Trans.Select

Methods

empty :: SelectT r m a Source #

(<|>) :: SelectT r m a -> SelectT r m a -> SelectT r m a Source #

some :: SelectT r m a -> SelectT r m [a] Source #

many :: SelectT r m a -> SelectT r m [a] Source #

(Functor m, Monad m) => Applicative (SelectT r m) Source # 
Instance details

Defined in Control.Monad.Trans.Select

Methods

pure :: a -> SelectT r m a Source #

(<*>) :: SelectT r m (a -> b) -> SelectT r m a -> SelectT r m b Source #

liftA2 :: (a -> b -> c) -> SelectT r m a -> SelectT r m b -> SelectT r m c Source #

(*>) :: SelectT r m a -> SelectT r m b -> SelectT r m b Source #

(<*) :: SelectT r m a -> SelectT r m b -> SelectT r m a Source #

Functor m => Functor (SelectT r m) Source # 
Instance details

Defined in Control.Monad.Trans.Select

Methods

fmap :: (a -> b) -> SelectT r m a -> SelectT r m b Source #

(<$) :: a -> SelectT r m b -> SelectT r m a Source #

Monad m => Monad (SelectT r m) Source # 
Instance details

Defined in Control.Monad.Trans.Select

Methods

(>>=) :: SelectT r m a -> (a -> SelectT r m b) -> SelectT r m b Source #

(>>) :: SelectT r m a -> SelectT r m b -> SelectT r m b Source #

return :: a -> SelectT r m a Source #

MonadPlus m => MonadPlus (SelectT r m) Source # 
Instance details

Defined in Control.Monad.Trans.Select

Methods

mzero :: SelectT r m a Source #

mplus :: SelectT r m a -> SelectT r m a -> SelectT r m a Source #

Generic (SelectT r m a) Source # 
Instance details

Defined in Control.Monad.Trans.Select

Associated Types

type Rep (SelectT r m a) 
Instance details

Defined in Control.Monad.Trans.Select

type Rep (SelectT r m a) = D1 ('MetaData "SelectT" "Control.Monad.Trans.Select" "transformers-0.6.1.0-2a04" 'True) (C1 ('MetaCons "SelectT" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 ((a -> m r) -> m a))))

Methods

from :: SelectT r m a -> Rep (SelectT r m a) x Source #

to :: Rep (SelectT r m a) x -> SelectT r m a Source #

type Rep (SelectT r m a) Source # 
Instance details

Defined in Control.Monad.Trans.Select

type Rep (SelectT r m a) = D1 ('MetaData "SelectT" "Control.Monad.Trans.Select" "transformers-0.6.1.0-2a04" 'True) (C1 ('MetaCons "SelectT" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 ((a -> m r) -> m a))))

runSelectT :: SelectT r m a -> (a -> m r) -> m a Source #

Runs a SelectT computation with a function for evaluating answers to select a particular answer. (The inverse of select.)

mapSelectT :: (m a -> m a) -> SelectT r m a -> SelectT r m a Source #

Apply a function to transform the result of a selection computation. This has a more restricted type than the map operations for other monad transformers, because SelectT does not define a functor in the category of monads.

Monad transformation

selectToContT :: forall (m :: Type -> Type) r a. Monad m => SelectT r m a -> ContT r m a Source #

Convert a selection computation to a continuation-passing computation.