logict-0.7.0.2: A backtracking logic-programming monad.

Copyright(c) Dan Doel
LicenseBSD3
Maintainerdan.doel@gmail.com
Stabilityexperimental
Portabilitynon-portable (multi-parameter type classes)
Safe HaskellSafe
LanguageHaskell98

Control.Monad.Logic

Contents

Description

A backtracking, logic programming monad.

Adapted from the paper /Backtracking, Interleaving, and Terminating Monad Transformers/, by Oleg Kiselyov, Chung-chieh Shan, Daniel P. Friedman, Amr Sabry (http://okmij.org/ftp/papers/LogicT.pdf).

Synopsis

Documentation

The Logic monad

type Logic = LogicT Identity Source #

The basic Logic monad, for performing backtracking computations returning values of type a.

logic :: (forall r. (a -> r -> r) -> r -> r) -> Logic a Source #

A smart constructor for Logic computations.

runLogic :: Logic a -> (a -> r -> r) -> r -> r Source #

Runs a Logic computation with the specified initial success and failure continuations.

observe :: Logic a -> a Source #

Extracts the first result from a Logic computation.

observeMany :: Int -> Logic a -> [a] Source #

Extracts up to a given number of results from a Logic computation.

observeAll :: Logic a -> [a] Source #

Extracts all results from a Logic computation.

The LogicT monad transformer

newtype LogicT m a Source #

A monad transformer for performing backtracking computations layered over another monad m.

Constructors

LogicT 

Fields

  • unLogicT :: forall r. (a -> m r -> m r) -> m r -> m r
     
Instances
MonadTrans LogicT Source # 
Instance details

Defined in Control.Monad.Logic

Methods

lift :: Monad m => m a -> LogicT m a #

MonadState s m => MonadState s (LogicT m) Source # 
Instance details

Defined in Control.Monad.Logic

Methods

get :: LogicT m s #

put :: s -> LogicT m () #

state :: (s -> (a, s)) -> LogicT m a #

MonadReader r m => MonadReader r (LogicT m) Source # 
Instance details

Defined in Control.Monad.Logic

Methods

ask :: LogicT m r #

local :: (r -> r) -> LogicT m a -> LogicT m a #

reader :: (r -> a) -> LogicT m a #

MonadError e m => MonadError e (LogicT m) Source # 
Instance details

Defined in Control.Monad.Logic

Methods

throwError :: e -> LogicT m a #

catchError :: LogicT m a -> (e -> LogicT m a) -> LogicT m a #

Monad (LogicT m) Source # 
Instance details

Defined in Control.Monad.Logic

Methods

(>>=) :: LogicT m a -> (a -> LogicT m b) -> LogicT m b #

(>>) :: LogicT m a -> LogicT m b -> LogicT m b #

return :: a -> LogicT m a #

fail :: String -> LogicT m a #

Functor (LogicT f) Source # 
Instance details

Defined in Control.Monad.Logic

Methods

fmap :: (a -> b) -> LogicT f a -> LogicT f b #

(<$) :: a -> LogicT f b -> LogicT f a #

MonadFail (LogicT m) Source # 
Instance details

Defined in Control.Monad.Logic

Methods

fail :: String -> LogicT m a #

Applicative (LogicT f) Source # 
Instance details

Defined in Control.Monad.Logic

Methods

pure :: a -> LogicT f a #

(<*>) :: LogicT f (a -> b) -> LogicT f a -> LogicT f b #

liftA2 :: (a -> b -> c) -> LogicT f a -> LogicT f b -> LogicT f c #

(*>) :: LogicT f a -> LogicT f b -> LogicT f b #

(<*) :: LogicT f a -> LogicT f b -> LogicT f a #

(Monad m, Foldable m) => Foldable (LogicT m) Source # 
Instance details

Defined in Control.Monad.Logic

Methods

fold :: Monoid m0 => LogicT m m0 -> m0 #

foldMap :: Monoid m0 => (a -> m0) -> LogicT m a -> m0 #

foldr :: (a -> b -> b) -> b -> LogicT m a -> b #

foldr' :: (a -> b -> b) -> b -> LogicT m a -> b #

foldl :: (b -> a -> b) -> b -> LogicT m a -> b #

foldl' :: (b -> a -> b) -> b -> LogicT m a -> b #

foldr1 :: (a -> a -> a) -> LogicT m a -> a #

foldl1 :: (a -> a -> a) -> LogicT m a -> a #

toList :: LogicT m a -> [a] #

null :: LogicT m a -> Bool #

length :: LogicT m a -> Int #

elem :: Eq a => a -> LogicT m a -> Bool #

maximum :: Ord a => LogicT m a -> a #

minimum :: Ord a => LogicT m a -> a #

sum :: Num a => LogicT m a -> a #

product :: Num a => LogicT m a -> a #

Foldable (LogicT Identity) Source # 
Instance details

Defined in Control.Monad.Logic

Methods

fold :: Monoid m => LogicT Identity m -> m #

foldMap :: Monoid m => (a -> m) -> LogicT Identity a -> m #

foldr :: (a -> b -> b) -> b -> LogicT Identity a -> b #

foldr' :: (a -> b -> b) -> b -> LogicT Identity a -> b #

foldl :: (b -> a -> b) -> b -> LogicT Identity a -> b #

foldl' :: (b -> a -> b) -> b -> LogicT Identity a -> b #

foldr1 :: (a -> a -> a) -> LogicT Identity a -> a #

foldl1 :: (a -> a -> a) -> LogicT Identity a -> a #

toList :: LogicT Identity a -> [a] #

null :: LogicT Identity a -> Bool #

length :: LogicT Identity a -> Int #

elem :: Eq a => a -> LogicT Identity a -> Bool #

maximum :: Ord a => LogicT Identity a -> a #

minimum :: Ord a => LogicT Identity a -> a #

sum :: Num a => LogicT Identity a -> a #

product :: Num a => LogicT Identity a -> a #

Traversable (LogicT Identity) Source # 
Instance details

Defined in Control.Monad.Logic

Methods

traverse :: Applicative f => (a -> f b) -> LogicT Identity a -> f (LogicT Identity b) #

sequenceA :: Applicative f => LogicT Identity (f a) -> f (LogicT Identity a) #

mapM :: Monad m => (a -> m b) -> LogicT Identity a -> m (LogicT Identity b) #

sequence :: Monad m => LogicT Identity (m a) -> m (LogicT Identity a) #

MonadIO m => MonadIO (LogicT m) Source # 
Instance details

Defined in Control.Monad.Logic

Methods

liftIO :: IO a -> LogicT m a #

Alternative (LogicT f) Source # 
Instance details

Defined in Control.Monad.Logic

Methods

empty :: LogicT f a #

(<|>) :: LogicT f a -> LogicT f a -> LogicT f a #

some :: LogicT f a -> LogicT f [a] #

many :: LogicT f a -> LogicT f [a] #

MonadPlus (LogicT m) Source # 
Instance details

Defined in Control.Monad.Logic

Methods

mzero :: LogicT m a #

mplus :: LogicT m a -> LogicT m a -> LogicT m a #

Monad m => MonadLogic (LogicT m) Source # 
Instance details

Defined in Control.Monad.Logic

Methods

msplit :: LogicT m a -> LogicT m (Maybe (a, LogicT m a)) Source #

interleave :: LogicT m a -> LogicT m a -> LogicT m a Source #

(>>-) :: LogicT m a -> (a -> LogicT m b) -> LogicT m b Source #

ifte :: LogicT m a -> (a -> LogicT m b) -> LogicT m b -> LogicT m b Source #

once :: LogicT m a -> LogicT m a Source #

lnot :: LogicT m a -> LogicT m () Source #

runLogicT :: LogicT m a -> (a -> m r -> m r) -> m r -> m r Source #

Runs a LogicT computation with the specified initial success and failure continuations.

observeT :: Monad m => LogicT m a -> m a Source #

Extracts the first result from a LogicT computation, failing otherwise.

observeManyT :: Monad m => Int -> LogicT m a -> m [a] Source #

Extracts up to a given number of results from a LogicT computation.

observeAllT :: Monad m => LogicT m a -> m [a] Source #

Extracts all results from a LogicT computation.