{- |

Module : $Header$

Copyright : (c) Felix Gabriel Mance

License : GPLv2 or higher, see LICENSE.txt

Maintainer : f.mance@jacobs-university.de

Stability : provisional

Portability : portable

RDF syntax parser

-}

module RDF.Parse where

import Common.Parsec

import Common.Lexer

import OWL2.AS

import OWL2.Parse

import RDF.AS

import RDF.Symbols

import Text.ParserCombinators.Parsec

-- * ntriples parser

-- | parses an object

parseObj :: CharParser st Object

parseObj = fmap Right literal <|> fmap Left uriP

-- | parses a comment

comment :: CharParser st ()

comment = do

skipChar '#'

forget $ manyTill anyChar $ char '\n'

-- | parses one ntriple (subject, predicate, object)

parseNTriple :: CharParser st Axiom

parseNTriple = do

many space

subj <- uriP

pre <- uriP

obj <- parseObj

skips $ char '.'

return $ Axiom subj pre obj

-- | parses a string containing several ntriples

basicSpec :: CharParser st RDFGraph

basicSpec = do

many $ forget space <|> comment

fmap RDFGraph $ many parseNTriple

-- | parses an ntriple file

parseNTriplesFile :: String -> IO RDFGraph

parseNTriplesFile file = do

str <- readFile file

case runParser (basicSpec << eof) () file str of

Right g -> return g

Left err -> error $ show err

-- * hets symbols parser

rdfEntityType :: CharParser st RDFEntityType

rdfEntityType = choice $ map (\ f -> keyword (show f) >> return f)

rdfEntityTypes

{- | parses an entity type (subject, predicate or object) followed by a

comma separated list of IRIs -}

rdfSymbItems :: GenParser Char st SymbItems

rdfSymbItems = do

ext <- optionMaybe rdfEntityType

iris <- rdfSymbs

return $ SymbItems ext iris

-- | parse a comma separated list of uris

rdfSymbs :: GenParser Char st [IRI]

rdfSymbs = uriP >>= \ u -> do

commaP `followedWith` uriP

us <- rdfSymbs

return $ u : us

<|> return [u]

-- | parse a possibly kinded list of comma separated symbol pairs

rdfSymbMapItems :: GenParser Char st SymbMapItems

rdfSymbMapItems = do

ext <- optionMaybe rdfEntityType

iris <- rdfSymbPairs

return $ SymbMapItems ext iris

-- | parse a comma separated list of uri pairs

rdfSymbPairs :: GenParser Char st [(IRI, Maybe IRI)]

rdfSymbPairs = uriPair >>= \ u -> do

commaP `followedWith` uriP

us <- rdfSymbPairs

return $ u : us

<|> return [u]