Language.Souffle.Class

This module provides the top level API for Souffle related operations. It makes use of Haskell's powerful typesystem to make certain invalid states impossible to represent. It does this with a small type level DSL for describing properties of the Datalog program (see the Program and Fact typeclasses for more information).

The Souffle operations are exposed via 2 mtl-style interfaces (see MonadSouffle and MonadSouffleFileIO) that allows them to be integrated with existing monad transformer stacks.

This module also contains some helper type families for additional type safety and user-friendly error messages.

Documentation

class Program a where

A typeclass for describing a datalog program.

Example usage (assuming the program was generated from path.dl and contains 2 facts: Edge and Reachable):

data Path = Path  -- Handle for the datalog program

instance Program Path where
  type ProgramFacts Path = '[Edge, Reachable]
  programName = const "path"

Associated Types

type ProgramFacts a :: [Type]

A type level list of facts that belong to this program. This list is used to check that only known facts are added to a program.

Methods

programName :: a -> String

Function for obtaining the name of a Datalog program. This has to be the same as the name of the .dl file (minus the extension).

Instances

KnownSymbol progName => Program (ProgramOptions prog progName facts)

Defined in Language.Souffle.Class

Associated Types

type ProgramFacts (ProgramOptions prog progName facts) :: [Type]

Methods

programName :: ProgramOptions prog progName facts -> String

newtype ProgramOptions (prog :: Type) (progName :: Symbol) (facts :: [Type])

A helper data type, used in combination with the DerivingVia extension to automatically generate code to bind Haskell to a Souffle Datalog program.

The following is an example how to bind to a Datalog program "path" (saved as path.dl / path.cpp), that uses two facts called "edge" and "reachable" (represented with the Edge and Reachable types):

data Path = Path
  deriving Souffle.Program
  via Souffle.ProgramOptions Path "path" '[Edge, Reachable]

See also: FactOptions.

Constructors

ProgramOptions prog

Instances

KnownSymbol progName => Program (ProgramOptions prog progName facts)

Defined in Language.Souffle.Class

Associated Types

type ProgramFacts (ProgramOptions prog progName facts) :: [Type]

Methods

programName :: ProgramOptions prog progName facts -> String

type ProgramFacts (ProgramOptions prog progName facts)

Defined in Language.Souffle.Class

type ProgramFacts (ProgramOptions prog progName facts) = facts

class Marshal a => Fact a where

A typeclass for data types representing a fact in datalog.

Example usage:

instance Fact Edge where
  type FactDirection Edge = 'Input
  factName = const "edge"

Associated Types

type FactDirection a :: Direction

The direction or "mode" a fact can be used in. This is used to perform compile-time checks that a fact is only used in valid situations. For more information, see the Direction type.

Methods

factName :: Proxy a -> String

Function for obtaining the name of a fact (has to be the same as described in the Datalog program).

It uses a Proxy to select the correct instance.

Instances

(Marshal fact, KnownSymbol factName) => Fact (FactOptions fact factName dir)

Defined in Language.Souffle.Class

Associated Types

type FactDirection (FactOptions fact factName dir) :: Direction

Methods

factName :: Proxy (FactOptions fact factName dir) -> String

newtype FactOptions (fact :: Type) (factName :: Symbol) (dir :: Direction)

A helper data type, used in combination with the DerivingVia extension to automatically generate code to bind a Haskell datatype to a Souffle Datalog fact.

The following is an example how to bind to a Datalog fact "edge" that contains two symbols (strings in Haskell) that is an input (from the Datalog point of view):

data Edge = Edge String String
  deriving (Eq, Show, Generic)
  deriving anyclass Souffle.Marshal
  deriving Souffle.Fact
  via Souffle.FactOptions Edge "edge" 'Souffle.Input

See also: ProgramOptions.

Constructors

FactOptions fact

Instances

(Marshal fact, KnownSymbol factName) => Fact (FactOptions fact factName dir)

Defined in Language.Souffle.Class

Associated Types

type FactDirection (FactOptions fact factName dir) :: Direction

Methods

factName :: Proxy (FactOptions fact factName dir) -> String

Marshal fact => Marshal (FactOptions fact name dir)

Defined in Language.Souffle.Class

Methods

push :: MonadPush m => FactOptions fact name dir -> m ()

pop :: MonadPop m => m (FactOptions fact name dir)

type FactDirection (FactOptions fact factName dir)

Defined in Language.Souffle.Class

type FactDirection (FactOptions fact factName dir) = dir

class Marshal a where

A typeclass for providing a uniform API to marshal/unmarshal values between Haskell and Souffle datalog.

The marshalling is done via a stack-based approach, where elements are pushed/popped one by one. You need to make sure that the marshalling of values happens in the correct order or unexpected things might happen (including crashes). Pushing and popping of fields should happen in the same order (from left to right, as defined in Datalog). The ordering of how nested products are serialized is the same as when the fields of the nested product types are inlined into the parent type.

Generic implementations for push and pop that perform the previously described behavior are available. This makes it possible to write very succinct code:

data Edge = Edge String String deriving Generic

instance Marshal Edge

Minimal complete definition

Nothing

Methods

push :: MonadPush m => a -> m ()

Marshals a value to the datalog side.

default push :: (Generic a, SimpleProduct a, GMarshal (Rep a), MonadPush m) => a -> m ()

pop :: MonadPop m => m a

Unmarshals a value from the datalog side.

default pop :: (Generic a, SimpleProduct a, GMarshal (Rep a), MonadPop m) => m a

Instances

Marshal Int32

Defined in Language.Souffle.Marshal

Methods

push :: MonadPush m => Int32 -> m ()

pop :: MonadPop m => m Int32

Marshal Word32

Defined in Language.Souffle.Marshal

Methods

push :: MonadPush m => Word32 -> m ()

pop :: MonadPop m => m Word32

Marshal Text

Defined in Language.Souffle.Marshal

Methods

push :: MonadPush m => Text -> m ()

pop :: MonadPop m => m Text

Marshal Text

Defined in Language.Souffle.Marshal

Methods

push :: MonadPush m => Text -> m ()

pop :: MonadPop m => m Text

Marshal ShortText

Defined in Language.Souffle.Marshal

Methods

push :: MonadPush m => ShortText -> m ()

pop :: MonadPop m => m ShortText

Marshal String

Defined in Language.Souffle.Marshal

Methods

push :: MonadPush m => String -> m ()

pop :: MonadPop m => m String

Marshal Float

Defined in Language.Souffle.Marshal

Methods

push :: MonadPush m => Float -> m ()

pop :: MonadPop m => m Float

Marshal fact => Marshal (FactOptions fact name dir)

Defined in Language.Souffle.Class

Methods

push :: MonadPush m => FactOptions fact name dir -> m ()

pop :: MonadPop m => m (FactOptions fact name dir)

data Direction

A datatype describing which operations a certain fact supports. The direction is from the datalog perspective, so that it aligns with ".decl" statements in Souffle.

Constructors

Input

Fact can only be stored in Datalog (using addFact/addFacts).

Output

Fact can only be read from Datalog (using getFacts/findFact).

InputOutput

Fact supports both reading from / writing to Datalog.

Internal

Supports neither reading from / writing to Datalog. This is used for facts that are only visible inside Datalog itself.

type family ContainsInputFact prog fact :: Constraint where ...

A helper type family for checking if a specific Souffle Program contains a certain Fact. Additionally, it also checks if the fact is marked as either Input or InputOutput. This constraint will generate a user-friendly type error if these conditions are not met.

Equations

ContainsInputFact prog fact = (ContainsFact prog fact, IsInput fact (FactDirection fact))

type family ContainsOutputFact prog fact :: Constraint where ...

A helper type family for checking if a specific Souffle Program contains a certain Fact. Additionally, it also checks if the fact is marked as either Output or InputOutput. This constraint will generate a user-friendly type error if these conditions are not met.

Equations

ContainsOutputFact prog fact = (ContainsFact prog fact, IsOutput fact (FactDirection fact))

type family ContainsFact prog fact :: Constraint where ...

A helper type family for checking if a specific Souffle Program contains a certain Fact. This constraint will generate a user-friendly type error if this is not the case.

Equations

ContainsFact prog fact = CheckContains prog (ProgramFacts prog) fact

class Monad m => MonadSouffle m where

A mtl-style typeclass for Souffle-related actions.

Associated Types

type Handler m :: Type -> Type

Represents a handle for interacting with a Souffle program.

The handle is used in all other functions of this typeclass to perform Souffle-related actions.

type CollectFacts m (c :: Type -> Type) :: Constraint

Helper associated type constraint that allows collecting facts from Souffle in a list or vector. Only used internally.

type SubmitFacts m (a :: Type) :: Constraint

Helper associated type constraint that allows submitting facts to Souffle. Only used internally.

Methods

run :: Handler m prog -> m ()

Runs the Souffle program.

setNumThreads :: Handler m prog -> Word64 -> m ()

Sets the number of CPU cores this Souffle program should use.

getNumThreads :: Handler m prog -> m Word64

Gets the number of CPU cores this Souffle program should use.

getFacts :: (Fact a, ContainsOutputFact prog a, CollectFacts m c) => Handler m prog -> m (c a)

Returns all facts of a program. This function makes use of type inference to select the type of fact to return.

findFact :: (Fact a, ContainsOutputFact prog a, Eq a, SubmitFacts m a) => Handler m prog -> a -> m (Maybe a)

Searches for a fact in a program. Returns Nothing if no matching fact was found; otherwise Just the fact.

Conceptually equivalent to List.find (== fact) <$> getFacts prog, but this operation can be implemented much faster.

addFact :: (Fact a, ContainsInputFact prog a, SubmitFacts m a) => Handler m prog -> a -> m ()

Adds a fact to the program.

addFacts :: (Foldable t, Fact a, ContainsInputFact prog a, SubmitFacts m a) => Handler m prog -> t a -> m ()

Adds multiple facts to the program. This function could be implemented in terms of addFact, but this is done as a minor optimization.

Instances

MonadSouffle SouffleM

Defined in Language.Souffle.Compiled

Associated Types

type Handler SouffleM :: Type -> Type

type CollectFacts SouffleM c

type SubmitFacts SouffleM a

Methods

run :: Handler SouffleM prog -> SouffleM ()

setNumThreads :: Handler SouffleM prog -> Word64 -> SouffleM ()

getNumThreads :: Handler SouffleM prog -> SouffleM Word64

getFacts :: (Fact a, ContainsOutputFact prog a, CollectFacts SouffleM c) => Handler SouffleM prog -> SouffleM (c a)

findFact :: (Fact a, ContainsOutputFact prog a, Eq a, SubmitFacts SouffleM a) => Handler SouffleM prog -> a -> SouffleM (Maybe a)

addFact :: (Fact a, ContainsInputFact prog a, SubmitFacts SouffleM a) => Handler SouffleM prog -> a -> SouffleM ()

addFacts :: (Foldable t, Fact a, ContainsInputFact prog a, SubmitFacts SouffleM a) => Handler SouffleM prog -> t a -> SouffleM ()

MonadSouffle SouffleM

Defined in Language.Souffle.Interpreted

Associated Types

type Handler SouffleM :: Type -> Type

type CollectFacts SouffleM c

type SubmitFacts SouffleM a

Methods

run :: Handler SouffleM prog -> SouffleM ()

setNumThreads :: Handler SouffleM prog -> Word64 -> SouffleM ()

getNumThreads :: Handler SouffleM prog -> SouffleM Word64

getFacts :: (Fact a, ContainsOutputFact prog a, CollectFacts SouffleM c) => Handler SouffleM prog -> SouffleM (c a)

findFact :: (Fact a, ContainsOutputFact prog a, Eq a, SubmitFacts SouffleM a) => Handler SouffleM prog -> a -> SouffleM (Maybe a)

addFact :: (Fact a, ContainsInputFact prog a, SubmitFacts SouffleM a) => Handler SouffleM prog -> a -> SouffleM ()

addFacts :: (Foldable t, Fact a, ContainsInputFact prog a, SubmitFacts SouffleM a) => Handler SouffleM prog -> t a -> SouffleM ()

MonadSouffle m => MonadSouffle (ExceptT e m)

Defined in Language.Souffle.Class

Associated Types

type Handler (ExceptT e m) :: Type -> Type

type CollectFacts (ExceptT e m) c

type SubmitFacts (ExceptT e m) a

Methods

run :: Handler (ExceptT e m) prog -> ExceptT e m ()

setNumThreads :: Handler (ExceptT e m) prog -> Word64 -> ExceptT e m ()

getNumThreads :: Handler (ExceptT e m) prog -> ExceptT e m Word64

getFacts :: (Fact a, ContainsOutputFact prog a, CollectFacts (ExceptT e m) c) => Handler (ExceptT e m) prog -> ExceptT e m (c a)

findFact :: (Fact a, ContainsOutputFact prog a, Eq a, SubmitFacts (ExceptT e m) a) => Handler (ExceptT e m) prog -> a -> ExceptT e m (Maybe a)

addFact :: (Fact a, ContainsInputFact prog a, SubmitFacts (ExceptT e m) a) => Handler (ExceptT e m) prog -> a -> ExceptT e m ()

addFacts :: (Foldable t, Fact a, ContainsInputFact prog a, SubmitFacts (ExceptT e m) a) => Handler (ExceptT e m) prog -> t a -> ExceptT e m ()

MonadSouffle m => MonadSouffle (ReaderT r m)

Defined in Language.Souffle.Class

Associated Types

type Handler (ReaderT r m) :: Type -> Type

type CollectFacts (ReaderT r m) c

type SubmitFacts (ReaderT r m) a

Methods

run :: Handler (ReaderT r m) prog -> ReaderT r m ()

setNumThreads :: Handler (ReaderT r m) prog -> Word64 -> ReaderT r m ()

getNumThreads :: Handler (ReaderT r m) prog -> ReaderT r m Word64

getFacts :: (Fact a, ContainsOutputFact prog a, CollectFacts (ReaderT r m) c) => Handler (ReaderT r m) prog -> ReaderT r m (c a)

findFact :: (Fact a, ContainsOutputFact prog a, Eq a, SubmitFacts (ReaderT r m) a) => Handler (ReaderT r m) prog -> a -> ReaderT r m (Maybe a)

addFact :: (Fact a, ContainsInputFact prog a, SubmitFacts (ReaderT r m) a) => Handler (ReaderT r m) prog -> a -> ReaderT r m ()

addFacts :: (Foldable t, Fact a, ContainsInputFact prog a, SubmitFacts (ReaderT r m) a) => Handler (ReaderT r m) prog -> t a -> ReaderT r m ()

MonadSouffle m => MonadSouffle (StateT s m)

Defined in Language.Souffle.Class

Associated Types

type Handler (StateT s m) :: Type -> Type

type CollectFacts (StateT s m) c

type SubmitFacts (StateT s m) a

Methods

run :: Handler (StateT s m) prog -> StateT s m ()

setNumThreads :: Handler (StateT s m) prog -> Word64 -> StateT s m ()

getNumThreads :: Handler (StateT s m) prog -> StateT s m Word64

getFacts :: (Fact a, ContainsOutputFact prog a, CollectFacts (StateT s m) c) => Handler (StateT s m) prog -> StateT s m (c a)

findFact :: (Fact a, ContainsOutputFact prog a, Eq a, SubmitFacts (StateT s m) a) => Handler (StateT s m) prog -> a -> StateT s m (Maybe a)

addFact :: (Fact a, ContainsInputFact prog a, SubmitFacts (StateT s m) a) => Handler (StateT s m) prog -> a -> StateT s m ()

addFacts :: (Foldable t, Fact a, ContainsInputFact prog a, SubmitFacts (StateT s m) a) => Handler (StateT s m) prog -> t a -> StateT s m ()

(Monoid w, MonadSouffle m) => MonadSouffle (WriterT w m)

Defined in Language.Souffle.Class

Associated Types

type Handler (WriterT w m) :: Type -> Type

type CollectFacts (WriterT w m) c

type SubmitFacts (WriterT w m) a

Methods

run :: Handler (WriterT w m) prog -> WriterT w m ()

setNumThreads :: Handler (WriterT w m) prog -> Word64 -> WriterT w m ()

getNumThreads :: Handler (WriterT w m) prog -> WriterT w m Word64

getFacts :: (Fact a, ContainsOutputFact prog a, CollectFacts (WriterT w m) c) => Handler (WriterT w m) prog -> WriterT w m (c a)

findFact :: (Fact a, ContainsOutputFact prog a, Eq a, SubmitFacts (WriterT w m) a) => Handler (WriterT w m) prog -> a -> WriterT w m (Maybe a)

addFact :: (Fact a, ContainsInputFact prog a, SubmitFacts (WriterT w m) a) => Handler (WriterT w m) prog -> a -> WriterT w m ()

addFacts :: (Foldable t, Fact a, ContainsInputFact prog a, SubmitFacts (WriterT w m) a) => Handler (WriterT w m) prog -> t a -> WriterT w m ()

(MonadSouffle m, Monoid w) => MonadSouffle (RWST r w s m)

Defined in Language.Souffle.Class

Associated Types

type Handler (RWST r w s m) :: Type -> Type

type CollectFacts (RWST r w s m) c

type SubmitFacts (RWST r w s m) a

Methods

run :: Handler (RWST r w s m) prog -> RWST r w s m ()

setNumThreads :: Handler (RWST r w s m) prog -> Word64 -> RWST r w s m ()

getNumThreads :: Handler (RWST r w s m) prog -> RWST r w s m Word64

getFacts :: (Fact a, ContainsOutputFact prog a, CollectFacts (RWST r w s m) c) => Handler (RWST r w s m) prog -> RWST r w s m (c a)

findFact :: (Fact a, ContainsOutputFact prog a, Eq a, SubmitFacts (RWST r w s m) a) => Handler (RWST r w s m) prog -> a -> RWST r w s m (Maybe a)

addFact :: (Fact a, ContainsInputFact prog a, SubmitFacts (RWST r w s m) a) => Handler (RWST r w s m) prog -> a -> RWST r w s m ()

addFacts :: (Foldable t, Fact a, ContainsInputFact prog a, SubmitFacts (RWST r w s m) a) => Handler (RWST r w s m) prog -> t a -> RWST r w s m ()

class MonadSouffle m => MonadSouffleFileIO m where

A mtl-style typeclass for Souffle-related actions that involve file IO.

Methods

loadFiles :: Handler m prog -> FilePath -> m ()

Load all facts from files in a certain directory.

writeFiles :: Handler m prog -> FilePath -> m ()

Write out all facts of the program to CSV files in a certain directory (as defined in the Souffle program).

Instances

MonadSouffleFileIO SouffleM

Defined in Language.Souffle.Compiled

Methods

loadFiles :: Handler SouffleM prog -> FilePath -> SouffleM ()

writeFiles :: Handler SouffleM prog -> FilePath -> SouffleM ()

MonadSouffleFileIO m => MonadSouffleFileIO (ExceptT s m)

Defined in Language.Souffle.Class

Methods

loadFiles :: Handler (ExceptT s m) prog -> FilePath -> ExceptT s m ()

writeFiles :: Handler (ExceptT s m) prog -> FilePath -> ExceptT s m ()

MonadSouffleFileIO m => MonadSouffleFileIO (ReaderT r m)

Defined in Language.Souffle.Class

Methods

loadFiles :: Handler (ReaderT r m) prog -> FilePath -> ReaderT r m ()

writeFiles :: Handler (ReaderT r m) prog -> FilePath -> ReaderT r m ()

MonadSouffleFileIO m => MonadSouffleFileIO (StateT s m)

Defined in Language.Souffle.Class

Methods

loadFiles :: Handler (StateT s m) prog -> FilePath -> StateT s m ()

writeFiles :: Handler (StateT s m) prog -> FilePath -> StateT s m ()

(Monoid w, MonadSouffleFileIO m) => MonadSouffleFileIO (WriterT w m)

Defined in Language.Souffle.Class

Methods

loadFiles :: Handler (WriterT w m) prog -> FilePath -> WriterT w m ()

writeFiles :: Handler (WriterT w m) prog -> FilePath -> WriterT w m ()

(MonadSouffleFileIO m, Monoid w) => MonadSouffleFileIO (RWST r w s m)

Defined in Language.Souffle.Class

Methods

loadFiles :: Handler (RWST r w s m) prog -> FilePath -> RWST r w s m ()

writeFiles :: Handler (RWST r w s m) prog -> FilePath -> RWST r w s m ()