{- |

Module : $Header$

Copyright : (c) Francisc-Nicolae Bungiu

License : GPLv2 or higher, see LICENSE.txt

Maintainer : Christian.Maeder@dfki.de

Stability : provisional

Portability : portable

RDF abstract syntax

References:

<http://www.informatik.uni-bremen.de/~till/papers/ontotrans.pdf>

<http://www.w3.org/TR/rdf-concepts/#section-Graph-syntax>

-}

module RDF.AS where

import Common.Id

import OWL2.AS

-- * Graphs

type Subject = IRI

type Predicate = IRI

type Object = Either IRI Literal

getIRIFromObject :: Object -> Maybe IRI

getIRIFromObject obj = case obj of

Left iri -> Just iri

_ -> Nothing

-- Axiom represents a RDF Triple

data Axiom = Axiom Subject Predicate Object

deriving (Show, Eq, Ord)

data RDFGraph = RDFGraph [Axiom]

deriving (Show, Eq, Ord)

data RDFEntityType = Subject | Predicate | Object

deriving (Show, Eq, Ord, Bounded, Enum)

data RDFEntity = RDFEntity RDFEntityType IRI

deriving (Show, Eq, Ord)

rdfEntityTypes :: [RDFEntityType]

rdfEntityTypes = [minBound .. maxBound]

instance GetRange RDFGraph where

instance GetRange Axiom where

instance GetRange RDFEntity where