Copyright	(c) Ross Paterson 2017
License	BSD-style (see the file LICENSE)
Maintainer	[email protected]
Stability	experimental
Portability	portable
Safe Haskell	Safe
Language	Haskell98

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.

• runSelect (mapSelect f m) = f . runSelect m

The SelectT monad transformer

newtype SelectT r m a Source

Selection monad transformer.

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

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 (mapSelectT f m) = f . runSelectT m

Monad transformation

selectToContT :: Monad m => SelectT r m a -> ContT r m a Source

Convert a selection computation to a continuation-passing computation.

selectToCont :: Monad m => SelectT r m a -> ContT r m a Source

Deprecated name for selectToContT.