TripLL

Gives a basic interface to a triple store. See homepage for an example.

Base Types for Accesing and Querying

class Triplestore h b | h -> b where

The Triplestore typeclass is an interface for triple stores. Every backend of this library uses this interface.

Methods

put :: Triple b -> h -> IO ()

most simple actions, a triple store has to support, put and del of triples:

del :: Triple b -> h -> IO ()

batch :: [BatchAction b] -> h -> IO ()

doing several simple actions in one go, one can use batch.

query :: QueryTriple b -> h -> IO [Triple b]

querying triples is done by filling in the known fields with 'Just x'.

withTrip :: FilePath -> (h -> IO a) -> IO a

createAndOpen :: FilePath -> IO h

open :: FilePath -> IO h

close :: h -> IO ()

data Triple a

A Triple is just anything consisting of three ordered pieces.

Constructors

Triple

Fields

subject :: a

predicate :: a

object :: a

data TriplePosition

TriplePosition gives a type for the fields within a Triple.

Constructors

Subject

Predicate

Object

Instances

Eq TriplePosition

Show TriplePosition

flatten :: Triple a -> (a, a, a)

flatten forgets about the description of the fields.

type QueryTriple a = Triple (Maybe a)

QueryTriple is a shorthand for Triple where the argument is encapsulated within a Maybe.

data BatchAction a

A BatchAction is either a Put or a Delete, i.e. either a `write given triple into database` or a `delete given triple from database`.

Constructors

Put (Triple a)

Delete (Triple a)