| Copyright | (c) Ross Paterson 2017 |
|---|---|
| License | BSD-style (see the file LICENSE) |
| Maintainer | R.Paterson@city.ac.uk |
| Stability | experimental |
| Portability | portable |
| Safe Haskell | Safe |
| Language | Haskell2010 |
Control.Monad.Trans.Select
Description
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
Synopsis
- type Select r = SelectT r Identity
- select :: ((a -> r) -> a) -> Select r a
- runSelect :: Select r a -> (a -> r) -> a
- mapSelect :: (a -> a) -> Select r a -> Select r a
- newtype SelectT r (m :: Type -> Type) a = SelectT ((a -> m r) -> m a)
- runSelectT :: SelectT r m a -> (a -> m r) -> m a
- mapSelectT :: (m a -> m a) -> SelectT r m a -> SelectT r m a
- selectToContT :: forall (m :: Type -> Type) r a. Monad m => SelectT r m a -> ContT r m a
The Select 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.)
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
| MonadTrans (SelectT r) Source # | |||||
| MonadFail m => MonadFail (SelectT r m) Source # | |||||
| MonadIO m => MonadIO (SelectT r m) Source # | |||||
| (Functor m, MonadPlus m) => Alternative (SelectT r m) Source # | |||||
| (Functor m, Monad m) => Applicative (SelectT r m) Source # | |||||
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 # | |||||
| Monad m => Monad (SelectT r m) Source # | |||||
| MonadPlus m => MonadPlus (SelectT r m) Source # | |||||
| Generic (SelectT r m a) Source # | |||||
Defined in Control.Monad.Trans.Select Associated Types
| |||||
| type Rep (SelectT r m a) Source # | |||||
Defined in Control.Monad.Trans.Select | |||||
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.
runSelectT(mapSelectTf m) = f .runSelectTm