Moduletransformers-0.6.3.0Haskell2010

Control.Monad.Trans.Select

Selection monad transformer, modelling search algorithms.

Martin Escardo and Paulo Oliva. "Selection functions, bar recursion and backward induction", Mathematical Structures in Computer Science 20:2 (2010), pp. 127-168. https://www.cs.bham.ac.uk/~mhe/papers/selection-escardo-oliva.pdf
Jules Hedges. "Monad transformers for backtracking search". In Proceedings of MSFP 2014. https://arxiv.org/abs/1406.2058

2 types
5 values

Packagetransformers-0.6.3.0
Exports7
LanguageHaskell2010
LicenceBSD-3-Clause
SourceSelect.hs

The Select monad

4 declarations

typetype Select r = SelectT r Identity

The selection monad, which is non-strict.

valueselect :: ((a -> r) -> a) -> Select r a

Constructor for computations in the selection monad.

valuerunSelect :: Select r a -> (a -> r) -> a

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

valuemapSelect :: (a -> a) -> Select r a -> Select r a

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

runSelect (mapSelect f m) = f . runSelect m

The SelectT monad transformer

2 declarations

newtypenewtype SelectT r (m :: Type -> Type) a

Selection monad transformer.

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

SelectT r m is strict if and only if m is.

Constructors

SelectT
- runSelectT :: (a -> m r) -> m a
  Runs a SelectT computation with a function for evaluating answers to select a particular answer.

Instances10MonadTrans, Monad, Functor, MonadFail, Applicative, Alternative, …

MonadTrans (SelectT r)Defined in transformers-0.6.3.0 · Control.Monad.Trans.Select
Monad m => Monad (SelectT r m)Defined in transformers-0.6.3.0 · Control.Monad.Trans.Select
Functor m => Functor (SelectT r m)Defined in transformers-0.6.3.0 · Control.Monad.Trans.Select
MonadFail m => MonadFail (SelectT r m)Defined in transformers-0.6.3.0 · Control.Monad.Trans.Select
(Functor m, Monad m) => Applicative (SelectT r m)Defined in transformers-0.6.3.0 · Control.Monad.Trans.Select
(Functor m, MonadPlus m) => Alternative (SelectT r m)Defined in transformers-0.6.3.0 · Control.Monad.Trans.Select
MonadPlus m => MonadPlus (SelectT r m)Defined in transformers-0.6.3.0 · Control.Monad.Trans.Select
MonadIO m => MonadIO (SelectT r m)Defined in transformers-0.6.3.0 · Control.Monad.Trans.Select
Generic (SelectT r m a)Defined in transformers-0.6.3.0 · Control.Monad.Trans.Select
type Rep (SelectT r m a) = D1 ('MetaData "SelectT" "Control.Monad.Trans.Select" "transformers-0.6.3.0-24a4" 'True) (C1 ('MetaCons "SelectT" 'PrefixI 'True) (S1 ('MetaSel ('Just "runSelectT") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 ((a -> m r) -> m a))))Defined in transformers-0.6.3.0 · Control.Monad.Trans.Select

valuemapSelectT :: (m a -> m a) -> SelectT r m a -> SelectT r m a

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.

runSelectT (mapSelectT f m) = f . runSelectT m

Monad transformation

1 declaration

valueselectToContT :: Monad m => SelectT r m a -> ContT r m a

Convert a selection computation to a continuation-passing computation.