| Safe Haskell | None |
|---|---|
| Language | Haskell2010 |
Language.Souffle.Interpreted
Description
This module provides an implementation for the MonadSouffle typeclass
defined in Language.Souffle.Class.
It makes use of the Souffle interpreter and CSV files to offer an
implementation optimized for quick development speed compared to
Language.Souffle.Compiled.
It is however much slower so users are advised to switch over to the compiled alternative once the prototyping phase is finished.
Synopsis
- class Program a where
- type ProgramFacts a :: [Type]
- programName :: Proxy a -> String
- class Marshal a => Fact a where
- class Marshal a where
- data Config = Config {}
- data Handle prog
- data SouffleM a
- class Monad m => MonadSouffle m where
- type Handler m :: Type -> Type
- type CollectFacts m (c :: Type -> Type) :: Constraint
- init :: Program prog => prog -> m (Maybe (Handler m prog))
- run :: Handler m prog -> m ()
- setNumThreads :: Handler m prog -> Word64 -> m ()
- getNumThreads :: Handler m prog -> m Word64
- getFacts :: (Fact a, ContainsFact prog a, CollectFacts m c) => Handler m prog -> m (c a)
- findFact :: (Fact a, ContainsFact prog a, Eq a) => Handler m prog -> a -> m (Maybe a)
- addFact :: (Fact a, ContainsFact prog a) => Handler m prog -> a -> m ()
- addFacts :: (Foldable t, Fact a, ContainsFact prog a) => Handler m prog -> t a -> m ()
- runSouffle :: SouffleM a -> IO a
- runSouffleWith :: Config -> SouffleM a -> IO a
- defaultConfig :: MonadIO m => m Config
- cleanup :: forall prog. Program prog => Handle prog -> SouffleM ()
- souffleStdOut :: forall prog. Program prog => Handle prog -> SouffleM (Maybe Text)
- souffleStdErr :: forall prog. Program prog => Handle prog -> SouffleM (Maybe Text)
Documentation
class Program a where Source #
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] Source #
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.
class Marshal a where Source #
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).
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 () Source #
Marshals a value to the datalog side.
pop :: MonadPop m => m a Source #
Unmarshals a value from the datalog side.
push :: (Generic a, SimpleProduct a (Rep a), GMarshal (Rep a), MonadPush m) => a -> m () Source #
Marshals a value to the datalog side.
pop :: (Generic a, SimpleProduct a (Rep a), GMarshal (Rep a), MonadPop m) => m a Source #
Unmarshals a value from the datalog side.
A helper data type for storing the configurable settings of the interpreter.
- cfgDatalogDir: The directory where the datalog file(s) are located.
- cfgSouffleBin: The name of the souffle binary. Has to be available in
$PATH or an absolute path needs to be provided. Note: Passing in
Nothingwill fail to start up the interpreter in theinitfunction. - cfgFactDir: The directory where the initial input fact file(s) can be found if present. If Nothing, then a temporary directory will be used, during the souffle session.
- cfgOutputDir: The directory where the output facts file(s) are created. If Nothing, it will be part of the temporary directory.
Constructors
| Config | |
Fields | |
A datatype representing a handle to a datalog program. The type parameter is used for keeping track of which program type the handle belongs to for additional type safety.
A monad for executing Souffle-related actions in.
Instances
class Monad m => MonadSouffle m where Source #
A mtl-style typeclass for Souffle-related actions.
Associated Types
type Handler m :: Type -> Type Source #
Represents a handle for interacting with a Souffle program.
See also init, which returns a handle of this type.
type CollectFacts m (c :: Type -> Type) :: Constraint Source #
Helper associated type constraint that allows collecting facts from Souffle in a list or vector. Only used internally.
Methods
init :: Program prog => prog -> m (Maybe (Handler m prog)) Source #
Initializes a Souffle program.
The action will return Nothing if it failed to load the Souffle C++
program or if it failed to find the Souffle interpreter (depending on
compiled/interpreted variant).
Otherwise it will return a handle that can be used in other functions
in this module.
run :: Handler m prog -> m () Source #
Runs the Souffle program.
setNumThreads :: Handler m prog -> Word64 -> m () Source #
Sets the number of CPU cores this Souffle program should use.
getNumThreads :: Handler m prog -> m Word64 Source #
Gets the number of CPU cores this Souffle program should use.
getFacts :: (Fact a, ContainsFact prog a, CollectFacts m c) => Handler m prog -> m (c a) Source #
Returns all facts of a program. This function makes use of type inference to select the type of fact to return.
findFact :: (Fact a, ContainsFact prog a, Eq a) => Handler m prog -> a -> m (Maybe a) Source #
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, ContainsFact prog a) => Handler m prog -> a -> m () Source #
Adds a fact to the program.
addFacts :: (Foldable t, Fact a, ContainsFact prog a) => Handler m prog -> t a -> m () Source #
Adds multiple facts to the program. This function could be implemented
in terms of addFact, but this is done as a minor optimization.
Instances
runSouffle :: SouffleM a -> IO a Source #
Returns an IO action that will run the Souffle interpreter with
default settings (see defaultConfig).
runSouffleWith :: Config -> SouffleM a -> IO a Source #
Returns an IO action that will run the Souffle interpreter with the given interpreter settings.
defaultConfig :: MonadIO m => m Config Source #
Retrieves the default config for the interpreter. These settings can be overridden using record update syntax if needed.
By default, the settings will be configured as follows:
- cfgDatalogDir: Looks at environment variable $DATALOG_DIR, falls back to the current directory if not set.
- cfgSouffleBin: Looks at environment variable $SOUFFLE_BIN, or tries to locate the souffle binary using the which shell command if the variable is not set.
- cfgFactDir: Will make use of a temporary directory.
- cfgOutputDir: Will make use of a temporary directory.
cleanup :: forall prog. Program prog => Handle prog -> SouffleM () Source #
Cleans up the temporary directory that this library has written files to. This functionality is only provided for the interpreted version since the compiled version directly (de-)serializes data via the C++ API.