{-# LANGUAGE OverloadedStrings #-} -- only used in 'fromMaybe "" mbase' line of parseN3 -------------------------------------------------------------------------------- -- See end of this file for licence information. -------------------------------------------------------------------------------- -- | -- Module : N3Parser -- Copyright : (c) 2003, Graham Klyne, 2009 Vasili I Galchin, 2011 Douglas Burke -- License : GPL V2 -- -- Maintainer : Douglas Burke -- Stability : experimental -- Portability : OverloadedStrings -- -- This Module implements a Notation 3 parser (see [1], [2], [3]), returning a -- new 'RDFGraph' consisting of triples and namespace information parsed from -- the supplied N3 input string, or an error indication. -- -- REFERENCES: -- -- 1 <http://www.w3.org/TeamSubmission/2008/SUBM-n3-20080114/> -- Notation3 (N3): A readable RDF syntax, -- W3C Team Submission 14 January 2008 -- -- 2 <http://www.w3.org/DesignIssues/Notation3.html> -- Tim Berners-Lee's design issues series notes and description -- -- 3 <http://www.w3.org/2000/10/swap/Primer.html> -- Notation 3 Primer by Sean Palmer -- -- NOTES: -- -- UTF-8 handling is not really tested. -- -- No performance testing has been applied. -- -- Not all N3 grammar elements are supported, including: -- -- - @\@forSome@ (we read it in but ignore the arguments) -- -- - @\@forAll@ (this causes a parse error) -- -- - formulae are lightly tested -- -- - string support is incomplete (e.g. unrecognized escape characters -- such as @\\q@ are probably handled incorrectly) -- -------------------------------------------------------------------------------- module Swish.RDF.N3Parser ( ParseResult , parseN3 , parseN3fromText , parseAnyfromText , parseTextFromText, parseAltFromText , parseNameFromText -- , parsePrefixFromText , parseAbsURIrefFromText, parseLexURIrefFromText, parseURIref2FromText -- * Exports for parsers that embed Notation3 in a bigger syntax , N3Parser, N3State(..), SpecialMap , getPrefix -- a combination of the old defaultPrefix and namedPrefix productions , n3symbol -- replacement for uriRef2 -- TODO: check this is semantically correct , quickVariable -- was varid , lexUriRef , document, subgraph , newBlankNode ) where import Swish.RDF.RDFGraph ( RDFGraph, RDFLabel(..) , ToRDFLabel(..) , NamespaceMap , LookupFormula(..) , addArc , setFormula , setNamespaces , emptyRDFGraph ) import Swish.RDF.GraphClass (arc) import Swish.Utils.LookupMap ( LookupMap(..) , LookupEntryClass(..) , mapFind, mapFindMaybe, mapReplaceOrAdd, mapAdd, mapReplace ) import Swish.Utils.Namespace ( Namespace, makeNamespace , ScopedName , getScopeNamespace , getScopedNameURI , getScopeNamespace , makeURIScopedName , makeQNameScopedName , makeNSScopedName , nullScopedName ) import Swish.Utils.QName (QName) import Swish.RDF.Vocabulary ( langName , rdfType , rdfFirst, rdfRest, rdfNil , owlSameAs, logImplies , xsdBoolean, xsdInteger, xsdDecimal, xsdDouble ) import Swish.RDF.RDFParser ( SpecialMap , ParseResult -- , mapPrefix , prefixTable , specialTable , ignore , notFollowedBy , endBy , sepEndBy , manyTill , noneOf , char , ichar , string , stringT , symbol , lexeme , whiteSpace , mkTypedLit , hex4 , hex8 , appendURIs ) import Control.Applicative import Control.Monad (forM_, foldM) import Network.URI (URI(..), parseURIReference) import Data.Char (isSpace, isDigit, ord) import Data.Maybe (fromMaybe, fromJust) import qualified Data.Text as T import qualified Data.Text.Lazy as L import Text.ParserCombinators.Poly.StateText ---------------------------------------------------------------------- -- Define parser state and helper functions ---------------------------------------------------------------------- -- | N3 parser state data N3State = N3State { graphState :: RDFGraph -- Graph under construction , thisNode :: RDFLabel -- current context node (aka 'this') , prefixUris :: NamespaceMap -- namespace prefix mapping table , syntaxUris :: SpecialMap -- special name mapping table , nodeGen :: Int -- blank node id generator , keywordsList :: [T.Text] -- contents of the @keywords statement , allowLocalNames :: Bool -- True if @keywords used so that bare names are QNames in default namespace } -- | Functions to update N3State vector (use with stUpdate) setPrefix :: Maybe T.Text -> URI -> N3State -> N3State setPrefix pre uri st = st { prefixUris=p' } where p' = mapReplaceOrAdd (makeNamespace pre uri) (prefixUris st) -- | Set name for special syntax element setSName :: String -> ScopedName -> N3State -> N3State setSName nam snam st = st { syntaxUris=s' } where s' = mapReplaceOrAdd (nam,snam) (syntaxUris st) setSUri :: String -> URI -> N3State -> N3State setSUri nam = setSName nam . makeURIScopedName -- | Set the list of tokens that can be used without needing the leading -- \@ symbol. setKeywordsList :: [T.Text] -> N3State -> N3State setKeywordsList ks st = st { keywordsList = ks, allowLocalNames = True } -- Functions to access state: -- | Get name for special syntax element, default null getSName :: N3State -> String -> ScopedName getSName st nam = mapFind nullScopedName nam (syntaxUris st) getSUri :: N3State -> String -> URI getSUri st nam = getScopedNameURI $ getSName st nam -- Map prefix to URI getPrefixURI :: N3State -> Maybe T.Text -> Maybe URI getPrefixURI st pre = mapFindMaybe pre (prefixUris st) getKeywordsList :: N3State -> [T.Text] getKeywordsList = keywordsList getAllowLocalNames :: N3State -> Bool getAllowLocalNames = allowLocalNames -- Return function to update graph in N3 parser state, -- using the supplied function of a graph -- updateGraph :: (RDFGraph -> RDFGraph) -> N3State -> N3State updateGraph f s = s { graphState = f (graphState s) } ---------------------------------------------------------------------- -- Define top-level parser function: -- accepts a string and returns a graph or error ---------------------------------------------------------------------- type N3Parser a = Parser N3State a -- | Parse a string as N3 (with no real base URI). -- -- See 'parseN3' if you need to provide a base URI. -- parseN3fromText :: L.Text -- ^ input in N3 format. -> ParseResult parseN3fromText = flip parseN3 Nothing -- | Parse a string with an optional base URI. -- -- See also 'parseN3fromString'. -- parseN3 :: L.Text -- ^ input in N3 format. -> Maybe QName -- ^ optional base URI -> ParseResult parseN3 txt mbase = parseAnyfromText document mbase txt {- -- useful for testing test :: String -> RDFGraph test = either error id . parseAnyfromString document Nothing -} hashURI :: URI hashURI = fromJust $ parseURIReference "#" -- TODO: change from QName to URI for the base? -- | Function to supply initial context and parse supplied term. -- parseAnyfromText :: N3Parser a -- ^ parser to apply -> Maybe QName -- ^ base URI of the input, or @Nothing@ to use default base value -> L.Text -- ^ input to be parsed -> Either String a parseAnyfromText parser mbase input = let pmap = LookupMap [makeNamespace Nothing hashURI] muri = fmap (makeQNameScopedName Nothing) mbase smap = LookupMap $ specialTable muri pstate = N3State { graphState = emptyRDFGraph , thisNode = NoNode , prefixUris = pmap , syntaxUris = smap , nodeGen = 0 , keywordsList = ["a", "is", "of", "true", "false"] -- not 100% sure about true/false here , allowLocalNames = False } (result, _, _) = runParser parser pstate input in result newBlankNode :: N3Parser RDFLabel newBlankNode = do n <- stQuery (succ . nodeGen) stUpdate $ \s -> s { nodeGen = n } return $ Blank (show n) -- Test functions for selected element parsing -- TODO: remove these parseTextFromText :: String -> L.Text -> Either String String parseTextFromText s = parseAnyfromText (string s) Nothing parseAltFromText :: String -> String -> L.Text -> Either String String parseAltFromText s1 s2 = parseAnyfromText (string s1 <|> string s2) Nothing parseNameFromText :: L.Text -> Either String String parseNameFromText = parseAnyfromText n3NameStr Nothing {- This has been made tricky by the attempt to remove the default list of prefixes from the starting point of a N3 parse and the subsequent attempt to add every new namespace we come across to the parser state. So we add in the original default namespaces for testing, since this routine is really for testing. -} addTestPrefixes :: N3Parser () addTestPrefixes = stUpdate $ \st -> st { prefixUris = LookupMap prefixTable } -- should append to existing map {- parsePrefixFromText :: L.Text -> Either String URI parsePrefixFromText = parseAnyfromText p Nothing where p = do addTestPrefixes pref <- n3Name st <- stGet case getPrefixURI st (Just pref) of Just uri -> return uri _ -> fail $ "Undefined prefix: '" ++ pref ++ "'" -} parseAbsURIrefFromText :: L.Text -> Either String URI parseAbsURIrefFromText = parseAnyfromText explicitURI Nothing parseLexURIrefFromText :: L.Text -> Either String URI parseLexURIrefFromText = parseAnyfromText lexUriRef Nothing parseURIref2FromText :: L.Text -> Either String ScopedName parseURIref2FromText = parseAnyfromText (addTestPrefixes *> n3symbol) Nothing ---------------------------------------------------------------------- -- Syntax productions ---------------------------------------------------------------------- -- helper routines comma, semiColon , fullStop :: N3Parser () comma = ignore $ symbol "," semiColon = ignore $ symbol ";" fullStop = ignore $ symbol "." -- a specialization of bracket/between br :: String -> String -> N3Parser a -> N3Parser a br lsym rsym = bracket (symbol lsym) (symbol rsym) -- to make porting from parsec to polyparse easier between :: Parser s lbr -> Parser s rbr -> Parser s a -> Parser s a between = bracket -- The @ character is optional if the keyword is in the -- keyword list -- atSign :: T.Text -> N3Parser () atSign s = do st <- stGet let p = ichar '@' if s `elem` getKeywordsList st then ignore $ optional p else p atWord :: T.Text -> N3Parser T.Text atWord s = do atSign s -- TODO: does it really make sense to add the not-followed-by-a-colon rule here? -- apply to both cases even though should only really be necessary -- when the at sign is not given -- lexeme $ stringT s *> notFollowedBy (== ':') return s {- Since operatorLabel can be used to add a label with an unknown namespace, we need to ensure that the namespace is added if not known. If the namespace prefix is already in use then it is over-written (rather than add a new prefix for the label). TODO: - could we use the reverse lookupmap functionality to find if the given namespace URI is in the namespace list? If it is, use it's key otherwise do a mapReplaceOrAdd for the input namespace. -} operatorLabel :: ScopedName -> N3Parser RDFLabel operatorLabel snam = do st <- stGet let sns = getScopeNamespace snam opmap = prefixUris st pkey = entryKey sns pval = entryVal sns rval = Res snam -- the lookup and the replacement could be fused case mapFindMaybe pkey opmap of Just val | val == pval -> return rval | otherwise -> do stUpdate $ \s -> s { prefixUris = mapReplace opmap sns } return rval _ -> do stUpdate $ \s -> s { prefixUris = mapAdd opmap sns } return rval {- Add statement to graph in N3 parser state. To support literals that are written directly/implicitly - i.e. as true/false/1/1.0/1.0e23 - rather than a string with an explicit datatype we need to special case handling of the object label for literals. Is this actually needed? The N3 Formatter now doesn't display the xsd: datatypes on output, but there may be issues with other formats (e.g RDF/XML once it is supported). -} type AddStatement = RDFLabel -> N3Parser () addStatement :: RDFLabel -> RDFLabel -> AddStatement addStatement s p o@(Lit _ (Just dtype)) | dtype `elem` [xsdBoolean, xsdInteger, xsdDecimal, xsdDouble] = do ost <- stGet let stmt = arc s p o oldp = prefixUris ost ogs = graphState ost newp = mapReplaceOrAdd (getScopeNamespace dtype) oldp stUpdate $ \st -> st { prefixUris = newp, graphState = addArc stmt ogs } addStatement s p o = stUpdate (updateGraph (addArc (arc s p o) )) addStatementRev :: RDFLabel -> RDFLabel -> AddStatement addStatementRev o p s = addStatement s p o {- A number of productions require a name, which starts with [A-Z_a-z#x00c0-#x00d6#x00d8-#x00f6#x00f8-#x02ff#x0370-#x037d#x037f-#x1fff#x200c-#x200d#x2070-#x218f#x2c00-#x2fef#x3001-#xd7ff#xf900-#xfdcf#xfdf0-#xfffd#x00010000-#x000effff] and then has [\-0-9A-Z_a-z#x00b7#x00c0-#x00d6#x00d8-#x00f6#x00f8-#x037d#x037f-#x1fff#x200c-#x200d#x203f-#x2040#x2070-#x218f#x2c00-#x2fef#x3001-#xd7ff#xf900-#xfdcf#xfdf0-#xfffd#x00010000-#x000effff]* we encode this as the n3Name production -} isaz, is09, isaz09 :: Char -> Bool isaz c = c >= 'a' && c <= 'z' is09 c = c >= '0' && c <= '9' isaz09 c = isaz c || is09 c startChar :: Char -> Bool startChar c = let i = ord c match :: (Ord a) => a -> [(a,a)] -> Bool match v = any (\(l,h) -> v >= l && v <= h) in c == '_' || match c [('A', 'Z'), ('a', 'z')] || match i [(0x00c0, 0x00d6), (0x00d8, 0x00f6), (0x00f8, 0x02ff), (0x0370, 0x037d), (0x037f, 0x1fff), (0x200c, 0x200d), (0x2070, 0x218f), (0x2c00, 0x2fef), (0x3001, 0xd7ff), (0xf900, 0xfdcf), (0xfdf0, 0xfffd), (0x00010000, 0x000effff)] inBody :: Char -> Bool inBody c = let i = ord c match :: (Ord a) => a -> [(a,a)] -> Bool match v = any (\(l,h) -> v >= l && v <= h) in c `elem` "-_" || i == 0x007 || match c [('0', '9'), ('A', 'Z'), ('a', 'z')] || match i [(0x00c0, 0x00d6), (0x00d8, 0x00f6), (0x00f8, 0x037d), (0x037f, 0x1fff), (0x200c, 0x200d), (0x203f, 0x2040), (0x2070, 0x218f), (0x2c00, 0x2fef), (0x3001, 0xd7ff), (0xf900, 0xfdcf), (0xfdf0, 0xfffd), (0x00010000, 0x000effff)] -- should this be strict or lazy text? n3Name :: N3Parser T.Text n3Name = T.cons <$> n3Init <*> n3Body where n3Init = satisfy startChar n3Body = L.toStrict <$> manySatisfy inBody n3NameStr :: N3Parser String n3NameStr = T.unpack <$> n3Name {- quickvariable ::= \?[A-Z_a-z#x00c0-#x00d6#x00d8-#x00f6#x00f8-#x02ff#x0370-#x037d#x037f-#x1fff#x200c-#x200d#x2070-#x218f#x2c00-#x2fef#x3001-#xd7ff#xf900-#xfdcf#xfdf0-#xfffd#x00010000-#x000effff][\-0-9A-Z_a-z#x00b7#x00c0-#x00d6#x00d8-#x00f6#x00f8-#x037d#x037f-#x1fff#x200c-#x200d#x203f-#x2040#x2070-#x218f#x2c00-#x2fef#x3001-#xd7ff#xf900-#xfdcf#xfdf0-#xfffd#x00010000-#x000effff]* -} -- TODO: is mapping to Var correct? quickVariable :: N3Parser RDFLabel quickVariable = char '?' *> (Var <$> n3NameStr) {- string ::= ("""[^"\\]*(?:(?:\\.|"(?!""))[^"\\]*)*""")|("[^"\\]*(?:\\.[^"\\]*)*") or string ::= tripleQuoted | singleQUoted -} n3string :: N3Parser T.Text n3string = tripleQuoted <|> singleQuoted {- singleQuoted ::= "[^"\\]*(?:\\.[^"\\]*)*" asciiChars :: String asciiChars = map chr [0x20..0x7e] asciiCharsN3 :: String asciiCharsN3 = filter (`notElem` "\\\"") asciiChars -} digit :: N3Parser Char digit = satisfy isDigit {- This is very similar to NTriples accept that also allow the escaping of ' even though it is not required. The Python rules allow \N{name}, where name is the Unicode name. It's not clear whether we need to support this too, so for now we do not. -} protectedChar :: N3Parser Char protectedChar = (char 't' *> return '\t') <|> (char 'n' *> return '\n') <|> (char 'r' *> return '\r') <|> (char '"' *> return '"') <|> (char '\'' *> return '\'') <|> (char '\\' *> return '\\') <|> (char 'u' *> hex4) <|> (char 'U' *> hex8) -- Accept an escape character or any character as long as it isn't -- a new-line or quote. Unrecognized escape sequences should therefore -- be left alone by this. -- n3Character :: N3Parser Char n3Character = (char '\\' *> (protectedChar <|> return '\\')) <|> noneOf "\"\n" {- <|> (oneOf asciiCharsN3 <?> "ASCII character") -- TODO: bodyChar and asciiCharsN3 overlap <|> (oneOf bodyChar <?> "Unicode character") -} sQuot :: N3Parser Char sQuot = char '"' {- TODO: there must be a better way of building up the Text -} singleQuoted :: N3Parser T.Text singleQuoted = fmap T.pack (bracket sQuot sQuot $ many n3Character) {- tripleQUoted ::= """[^"\\]*(?:(?:\\.|"(?!""))[^"\\]*)*""" -} tripleQuoted :: N3Parser T.Text tripleQuoted = tQuot *> fmap T.pack (manyTill (n3Character <|> sQuot <|> char '\n') tQuot) where -- tQuot = try (count 3 sQuot) tQuot = exactly 3 sQuot getDefaultPrefix :: N3Parser Namespace getDefaultPrefix = do s <- stGet case getPrefixURI s Nothing of Just uri -> return $ makeNamespace Nothing uri _ -> fail "No default prefix defined; how unexpected!" addBase :: URI -> N3Parser () addBase = stUpdate . setSUri "base" addPrefix :: Maybe T.Text -> URI -> N3Parser () addPrefix p = stUpdate . setPrefix p {-| Update the set of keywords that can be given without an \@ sign. -} updateKeywordsList :: [T.Text] -> N3Parser () updateKeywordsList = stUpdate . setKeywordsList {- document ::= | statements_optional EOF -} document :: N3Parser RDFGraph document = mkGr <$> (whiteSpace *> statementsOptional *> eof *> stGet) where mkGr s = setNamespaces (prefixUris s) (graphState s) {- statements_optional ::= | statement "." statements_optional | void -} statementsOptional :: N3Parser () statementsOptional = ignore $ endBy (lexeme statement) fullStop {- statement ::= | declaration | existential | simpleStatement | universal -} statement :: N3Parser () statement = declaration <|> existential <|> universal <|> simpleStatement -- having an error here leads to less informative errors in general, it seems -- <?> "statement (existential or universal quantification or a simple statement)" {- declaration ::= | "@base" explicituri | "@keywords" barename_csl | "@prefix" prefix explicituri -} -- TODO: do we need the try statements here? atWord would need to have a try on '@' -- (if applicable) which should mean being able to get rid of try -- declaration :: N3Parser () declaration = oneOf [ atWord "base" >> explicitURI >>= addBase, atWord "keywords" >> bareNameCsl >>= updateKeywordsList, atWord "prefix" *> getPrefix ] {- (try (atWord "base") >> explicitURI >>= addBase) <|> (try (atWord "keywords") >> bareNameCsl >>= updateKeywordsList) <|> (try (atWord "prefix") *> getPrefix) -} getPrefix :: N3Parser () getPrefix = do p <- lexeme prefix u <- explicitURI addPrefix p u {- explicituri ::= <[^>]*> Note: white space is to be ignored within <> -} explicitURI :: N3Parser URI explicitURI = do let lb = char '<' rb = char '>' -- TODO: do the whitespace definitions match? ustr <- between lb rb $ many (satisfy (/= '>')) let uclean = filter (not . isSpace) ustr case parseURIReference uclean of Nothing -> fail $ "Unable to convert <" ++ uclean ++ "> to a URI" Just uref -> do s <- stGet let base = getSUri s "base" either fail return $ appendURIs base uref -- production from the old parser; used in SwishScript lexUriRef :: N3Parser URI lexUriRef = lexeme explicitURI {- barename ::= [A-Z_a-z#x00c0-#x00d6#x00d8-#x00f6#x00f8-#x02ff#x0370-#x037d#x037f-#x1fff#x200c-#x200d#x2070-#x218f#x2c00-#x2fef#x3001-#xd7ff#xf900-#xfdcf#xfdf0-#xfffd#x00010000-#x000effff][\-0-9A-Z_a-z#x00b7#x00c0-#x00d6#x00d8-#x00f6#x00f8-#x037d#x037f-#x1fff#x200c-#x200d#x203f-#x2040#x2070-#x218f#x2c00-#x2fef#x3001-#xd7ff#xf900-#xfdcf#xfdf0-#xfffd#x00010000-#x000effff]* barename_csl ::= | barename barename_csl_tail | void barename_csl_tail ::= | "," barename barename_csl_tail | void -} bareNameCsl :: N3Parser [T.Text] bareNameCsl = sepBy (lexeme bareName) comma bareName :: N3Parser T.Text bareName = n3Name {- prefix ::= ([A-Z_a-z#x00c0-#x00d6#x00d8-#x00f6#x00f8-#x02ff#x0370-#x037d#x037f-#x1fff#x200c-#x200d#x2070-#x218f#x2c00-#x2fef#x3001-#xd7ff#xf900-#xfdcf#xfdf0-#xfffd#x00010000-#x000effff][\-0-9A-Z_a-z#x00b7#x00c0-#x00d6#x00d8-#x00f6#x00f8-#x037d#x037f-#x1fff#x200c-#x200d#x203f-#x2040#x2070-#x218f#x2c00-#x2fef#x3001-#xd7ff#xf900-#xfdcf#xfdf0-#xfffd#x00010000-#x000effff]*)?: -} prefix :: N3Parser (Maybe T.Text) prefix = optional (lexeme n3Name) <* char ':' {- symbol ::= | explicituri | qname symbol_csl ::= | symbol symbol_csl_tail | void symbol_csl_tail ::= | "," symbol symbol_csl_tail | void -} n3symbol :: N3Parser ScopedName n3symbol = (makeURIScopedName <$> explicitURI) <|> qname symbolCsl :: N3Parser [ScopedName] symbolCsl = sepBy (lexeme n3symbol) comma {- qname ::= (([A-Z_a-z#x00c0-#x00d6#x00d8-#x00f6#x00f8-#x02ff#x0370-#x037d#x037f-#x1fff#x200c-#x200d#x2070-#x218f#x2c00-#x2fef#x3001-#xd7ff#xf900-#xfdcf#xfdf0-#xfffd#x00010000-#x000effff][\-0-9A-Z_a-z#x00b7#x00c0-#x00d6#x00d8-#x00f6#x00f8-#x037d#x037f-#x1fff#x200c-#x200d#x203f-#x2040#x2070-#x218f#x2c00-#x2fef#x3001-#xd7ff#xf900-#xfdcf#xfdf0-#xfffd#x00010000-#x000effff]*)?:)?[A-Z_a-z#x00c0-#x00d6#x00d8-#x00f6#x00f8-#x02ff#x0370-#x037d#x037f-#x1fff#x200c-#x200d#x2070-#x218f#x2c00-#x2fef#x3001-#xd7ff#xf900-#xfdcf#xfdf0-#xfffd#x00010000-#x000effff][\-0-9A-Z_a-z#x00b7#x00c0-#x00d6#x00d8-#x00f6#x00f8-#x037d#x037f-#x1fff#x200c-#x200d#x203f-#x2040#x2070-#x218f#x2c00-#x2fef#x3001-#xd7ff#xf900-#xfdcf#xfdf0-#xfffd#x00010000-#x000effff]* TODO: Note that, for now, we explicitly handle blank nodes (of the form _:name) direcly in pathItem'. This is not a good idea since qname' is used elsewhere and so shouldn't we do the same thing there too? -} qname :: N3Parser ScopedName qname = -- (char ':' *> toSN getDefaultPrefix) (char ':' >> g >>= return . uncurry makeNSScopedName) <|> (n3Name >>= fullOrLocalQName) where g = (,) <$> getDefaultPrefix <*> (n3Name <|> return "") fullOrLocalQName :: T.Text -> N3Parser ScopedName fullOrLocalQName name = (char ':' *> fullQName name) <|> localQName name fullQName :: T.Text -> N3Parser ScopedName fullQName name = makeNSScopedName <$> findPrefix name <*> (n3Name <|> pure "") findPrefix :: T.Text -> N3Parser Namespace findPrefix pre = do st <- stGet case mapFindMaybe (Just pre) (prefixUris st) of Just uri -> return $ makeNamespace (Just pre) uri Nothing -> failBad $ "Prefix '" ++ T.unpack pre ++ ":' not bound." localQName :: T.Text -> N3Parser ScopedName localQName name = do st <- stGet if getAllowLocalNames st then let g = (,) <$> getDefaultPrefix <*> pure name in uncurry makeNSScopedName <$> g else fail ("Invalid 'bare' word: " ++ T.unpack name)-- TODO: not ideal error message; can we handle this case differently? {- existential ::= | "@forSome" symbol_csl For now we just read in the symbols and ignore them, since we do not mark blank nodes as existentially quantified (we assume this is the case). TODO: fix this? -} existential :: N3Parser () -- existential = try (atWord "forSome") *> symbolCsl >> return () existential = atWord "forSome" *> symbolCsl *> pure () {- simpleStatement ::= | subject propertylist -} simpleStatement :: N3Parser () simpleStatement = subject >>= propertyListWith {- subject ::= | expression -} subject :: N3Parser RDFLabel subject = lexeme expression {- expression ::= | pathitem pathtail pathtail ::= | "!" expression | "^" expression | void -} expression :: N3Parser RDFLabel expression = do i <- pathItem let backwardExpr = char '!' *> return addStatementRev forwardExpr = char '^' *> return addStatement mpt <- optional ( (,) <$> lexeme (forwardExpr <|> backwardExpr) <*> lexeme expression ) case mpt of Nothing -> return i Just (addFunc, pt) -> do bNode <- newBlankNode addFunc bNode pt i return bNode {- pathitem ::= | "(" pathlist ")" | "[" propertylist "]" | "{" formulacontent "}" | boolean | literal | numericliteral | quickvariable | symbol pathlist ::= | expression pathlist | void Need to think about how to handle formulae, since need to know the context of the call to know where to add them. TOOD: may include direct support for blank nodes here, namely convert _:stringval -> Blank stringval since although this should be done by symbol the types don't seem to easily match up (at first blush anyway) -} pathItem :: N3Parser RDFLabel pathItem = br "(" ")" pathList <|> br "[" "]" propertyListBNode <|> br "{" "}" formulaContent -- <|> try boolean <|> boolean <|> literal <|> numericLiteral <|> quickVariable <|> Blank <$> (string "_:" *> n3NameStr) -- TODO a hack that needs fixing <|> Res <$> n3symbol {- we create a blank node for the list and return it, whilst adding the list contents to the graph -} pathList :: N3Parser RDFLabel pathList = do cts <- many (lexeme expression) eNode <- operatorLabel rdfNil case cts of [] -> return eNode (c:cs) -> do sNode <- newBlankNode first <- operatorLabel rdfFirst addStatement sNode first c lNode <- foldM addElem sNode cs rest <- operatorLabel rdfRest addStatement lNode rest eNode return sNode where addElem prevNode curElem = do bNode <- newBlankNode first <- operatorLabel rdfFirst rest <- operatorLabel rdfRest addStatement prevNode rest bNode addStatement bNode first curElem return bNode {- formulacontent ::= | statementlist statementlist ::= | statement statementtail | void statementtail ::= | "." statementlist | void -} restoreState :: N3State -> N3Parser N3State restoreState origState = do oldState <- stGet stUpdate $ \_ -> origState { nodeGen = nodeGen oldState } return oldState {- We create a subgraph and assign it to a blank node, returning the blank node. At present it is a combination of the subgraph and formula productions from the origial parser. TODO: is it correct? -} formulaContent :: N3Parser RDFLabel formulaContent = do bNode <- newBlankNode pstate <- stGet stUpdate $ \st -> st { graphState = emptyRDFGraph, thisNode = bNode } statementList oldState <- restoreState pstate stUpdate $ updateGraph $ setFormula (Formula bNode (graphState oldState)) return bNode subgraph :: RDFLabel -> N3Parser RDFGraph subgraph this = do pstate <- stGet stUpdate $ \st -> st { graphState = emptyRDFGraph, thisNode = this } statementsOptional -- parse statements of formula oldState <- restoreState pstate return $ graphState oldState statementList :: N3Parser () statementList = ignore $ sepEndBy (lexeme statement) fullStop {- boolean ::= | "@false" | "@true" -} boolean :: N3Parser RDFLabel boolean = mkTypedLit xsdBoolean <$> (atWord "false" <|> atWord "true") -- (try (atWord "false") <|> atWord "true") {- dtlang ::= | "@" langcode | "^^" symbol | void literal ::= | string dtlang langcode ::= [a-z]+(-[a-z0-9]+)* -} literal :: N3Parser RDFLabel literal = Lit <$> n3string <*> optional dtlang dtlang :: N3Parser ScopedName dtlang = (char '@' *> langcode) <|> string "^^" *> n3symbol -- <|> (try (string "^^") *> n3symbol) langcode :: N3Parser ScopedName langcode = do h <- many1Satisfy isaz mt <- optional ( L.append <$> (char '-' *> pure (L.singleton '-')) <*> many1Satisfy isaz09) return $ langName $ L.toStrict $ L.append h (fromMaybe L.empty mt) {- decimal ::= [-+]?[0-9]+(\.[0-9]+)? double ::= [-+]?[0-9]+(\.[0-9]+)?([eE][-+]?[0-9]+) integer ::= [-+]?[0-9]+ numericliteral ::= | decimal | double | integer We actually support 1. for decimal values which isn't supported by the above production. TODO: we could convert via something like maybeRead value :: Double >>= Just . toRDFLabel which would mean we store the canonical XSD value in the label, but it is not useful for the xsd:decimal case since we currently don't have a Haskell type that goes with it. -} numericLiteral :: N3Parser RDFLabel numericLiteral = -- -- try (mkTypedLit xsdDouble <$> n3double) -- try (d2s <$> n3double) -- <|> try (mkTypedLit xsdDecimal <$> n3decimal) d2s <$> n3double <|> mkTypedLit xsdDecimal . T.pack <$> n3decimal <|> mkTypedLit xsdInteger . T.pack <$> n3integer n3sign :: N3Parser Char n3sign = char '+' <|> char '-' n3integer :: N3Parser String n3integer = do ms <- optional n3sign ds <- many1 digit case ms of Just s -> return $ s : ds _ -> return ds n3decimal :: N3Parser String -- n3decimal = (++) <$> n3integer <*> ( (:) <$> char '.' <*> many1 digit ) n3decimal = (++) <$> n3integer <*> ( (:) <$> char '.' <*> many digit ) n3double :: N3Parser String n3double = (++) <$> n3decimal <*> ( (:) <$> satisfy (`elem` "eE") <*> n3integer ) -- Convert a double, as returned by n3double, into it's -- canonical XSD form. We assume that n3double returns -- a syntactivally valid Double, so do not bother with reads here -- d2s :: String -> RDFLabel d2s s = toRDFLabel (read s :: Double) {- propertylist ::= | verb object objecttail propertylisttail | void propertylisttail ::= | ";" propertylist | void -} -- it's probably important that bNode is created *after* -- processing the plist (mainly for the assumptions made by -- formatting the output as N3; e.g. list/sequence ordering) -- propertyListBNode :: N3Parser RDFLabel propertyListBNode = do plist <- sepEndBy ((,) <$> lexeme verb <*> objectList) semiColon bNode <- newBlankNode let addList ((addFunc,vrb),items) = mapM_ (addFunc bNode vrb) items forM_ plist addList return bNode propertyListWith :: RDFLabel -> N3Parser () propertyListWith subj = let -- term = lexeme verb >>= objectListWith subj term = lexeme verb >>= \(addFunc, vrb) -> objectListWith (addFunc subj vrb) in ignore $ sepEndBy term semiColon {- object ::= | expression objecttail ::= | "," object objecttail | void We change the production rule from objecttail to objectlist for lists of objects (may change back). May be an optimisation needed in the case of :s :p :o1 , .. , :o<large number>. Is parsec creating the list of actions, using sepBy1 in objectListWith, and then evaluating them all once the list has been created? -} object :: N3Parser RDFLabel object = lexeme expression objectList :: N3Parser [RDFLabel] objectList = sepBy1 object comma objectWith :: AddStatement -> N3Parser () objectWith addFunc = object >>= addFunc objectListWith :: AddStatement -> N3Parser () objectListWith addFunc = ignore $ sepBy1 (objectWith addFunc) comma {- objectList1 :: N3Parser [RDFLabel] objectList1 = sepBy1 object comma -} {- verb ::= | "<=" | "=" | "=>" | "@a" | "@has" expression | "@is" expression "@of" | expression -} verb :: N3Parser (RDFLabel -> RDFLabel -> AddStatement, RDFLabel) verb = -- we check reverse first so that <= is tried before looking for a URI via expression rule (,) addStatementRev <$> verbReverse <|> (,) addStatement <$> verbForward -- those verbs for which subject is on the right and object on the left verbReverse :: N3Parser RDFLabel verbReverse = string "<=" *> operatorLabel logImplies <|> between (atWord "is") (atWord "of") (lexeme expression) {- try (string "<=") *> operatorLabel logImplies <|> between (try (atWord "is")) (atWord "of") (lexeme expression) -} -- those verbs with subject on the left and object on the right verbForward :: N3Parser RDFLabel verbForward = -- (try (string "=>") *> operatorLabel logImplies) (string "=>" *> operatorLabel logImplies) <|> (string "=" *> operatorLabel owlSameAs) -- <|> (try (atWord "a") *> operatorLabel rdfType) <|> (atWord "a" *> operatorLabel rdfType) <|> (atWord "has" *> lexeme expression) <|> lexeme expression {- universal ::= | "@forAll" symbol_csl TODO: what needs to be done to support universal quantification -} universal :: N3Parser () universal = -- try (atWord "forAll") *> atWord "forAll" *> failBad "universal (@forAll) currently unsupported." -- will be something like: *> symbolCsl {- -- OLD -- -- helper routines isymbol :: String -> N3Parser () isymbol s = symbol s >> return () -- document = directive* statement-list document :: N3Parser RDFGraph document = do whiteSpace _ <- many directive statements eof s <- getState return $ setNamespaces (prefixUris s) (graphState s) -- directive = "@prefix" prefix ":" uriRef2 "." // Namespace declaration -- | "@prefix" ":" uriRef2 "." // Default namespace -- | "@equivalence" uriRef2 "." // Alternative to daml:equivalent -- | "@listfirst" uriRef2 "." // Alternative to n3:first -- | "@listrest" uriRef2 "." // Alternative to n3:rest -- | "@listnull" uriRef2 "." // Alternative to n3:null -- | "@plus" uriRef2 "." // Alternative to operator:plus -- | "@minus" uriRef2 "." // Alternative to operator:minus -- | "@slash" uriRef2 "." // Alternative to operator:slash -- | "@star" uriRef2 "." // Alternative to operator:star -- | "@base" uriRef2 "." // Base URI for relative URIs. directive :: N3Parser () directive = (try (symbol "@prefix") >> (defaultPrefix <|> namedPrefix)) <|> (string "@" >> syntaxUri) <?> "directive" defaultPrefix :: N3Parser () defaultPrefix = do u <- br ":" "." uriRef2 updateState $ setPrefix "" (getScopedNameURI u) namedPrefix :: N3Parser () namedPrefix = do n <- name u <- br ":" "." uriRef2 updateState $ setPrefix n (getScopedNameURI u) syntaxUri :: N3Parser () syntaxUri = do s <- uriName u <- uriRef2 isymbol "." updateState $ setSUri s (getScopedNameURI u) uriName :: N3Parser String uriName = try (symbol "equivalence") <|> try (symbol "listfirst") <|> try (symbol "listrest") <|> try (symbol "listnull") <|> try (symbol "plus") <|> try (symbol "minus") <|> try (symbol "slash") <|> try (symbol "star") <|> try (symbol "base") <?> "special URI directive" -- statements = [ statement ( "." statement )* ] -- -- statement = subject property-list -- -- properties = [ property ( ";" property )* ] -- -- New statements are added to the user state graph statements :: N3Parser () statements = sepEndBy1 statement (symbol ".") >> return () statement :: N3Parser () -- statement = subject >>= optional . properties -- when using Parsec's optional statement = subject >>= optional . properties >> return () -- not sure this is exactly the same as with Parsec properties :: RDFLabel -> N3Parser () properties subj = sepBy1 (property subj) (symbol ";") >> return () -- property = verb object-list -- | ":-" anon-node // Creates anon-node aongside the current node -- verb = ">-" prop "->" // has 'prop' of -- | "<-" prop "<-" // is 'prop' of -- | operator // has operator:'operator' of (???) -- | prop // has 'prop' of -- shorthand -- | "has" prop "of" // has 'prop' of -- | "is" prop "of" // is 'prop' of -- | "a" // has rdf:type of -- | "=" // has daml:equivalent of -- -- subj is the subject node for these properties. -- -- New statements are added to the graph in the parser's user state. property :: RDFLabel -> N3Parser () property subj = (verb >>= uncurry (objects subj)) <|> (isymbol ":-" >> anonNode subj >> return ()) verb :: N3Parser (RDFLabel,Bool) verb = (prop >>= \p -> return (p, False)) <|> (operator >>= \p -> return (p, False)) <|> (br ">-" "->" prop >>= \p -> return (p, False)) <|> (br "<-" "<-" prop >>= \p -> return (p, True)) <|> (br "has" "of" prop >>= \p -> return (p, False)) <|> (br "is" "of" prop >>= \p -> return (p, True)) <|> (symbol "a" >> operatorLabel rdf_type >>= \lab -> return (lab, False)) <|> (symbol "=" >> operatorLabel owl_sameAs >>= \lab -> return (lab, False)) <?> "property" -- objects = object -- | object "," object-list -- -- subj is the subject node for the new statements, -- prop is the property node for the new statements. -- swap is true if the subject/object values in the resulting statement -- are to be swapped (for "is <prop> of", etc.) -- -- New statements are added to the graph in the parser's user state objects :: RDFLabel -> RDFLabel -> Bool -> N3Parser () objects subj ppty swap = sepBy1 (object subj ppty swap) (symbol ",") >> return () -- anonNode = "[" property-list "]" // Something with given properties -- | "{" statement-list "}" // List of statements as resource -- | "(" node-list ")" // Construct list with -- // rdf:first, rdf:rest, rdf:nil -- -- subj is the subject node with which the new anonymous node is equated, -- -- The anonymous node value is returned by this parser (which is often the same -- as the supplied subject node, but not always). -- -- New statements are added to the graph in the parser's user state -- (in the case of a formula, a new graph and parser are created, and -- the graph arcs are added to this new graph). anonNode :: RDFLabel -> N3Parser RDFLabel anonNode subj = (br "[" "]" (properties subj) >> return subj) <|> br "{" "}" (formula subj) <|> br "(" ")" (nodeList subj) <?> "anon node (\"[\", \"(\" or \"{\")" -- This method allows a statement list to be parsed as a subgraph -- whose value is associated with the supplied node of the current -- graph. formula :: RDFLabel -> N3Parser RDFLabel formula subj = do subgr <- subgraph subj updateState $ updateGraph $ setFormula (Formula subj subgr) return subj subgraph :: RDFLabel -> N3Parser RDFGraph subgraph this = do pstate <- getState let fstate = pstate { graphState = emptyRDFGraph, thisNode = this } setState fstate -- switch new state into parser statements -- parse statements of formula fstate' <- getState let nstate = pstate { nodeGen = nodeGen fstate' } setState nstate -- swap back state, with updated nodeGen return (graphState fstate') -- prop = uri-ref2 -- | varid -- -- Returns URI value as a Node prop :: N3Parser RDFLabel prop = nodeid <|> varid <|> uriNode -- operator = "+" // >- operator:plus -> -- | "-" // >- operator:minus -> -- | "/" // >- operator:slash -> -- | "*" // >- operator:star-> -- -- If matched, the operator is returned as a node value. operator :: N3Parser RDFLabel operator = (symbol "+" >> operatorLabel operator_plus) <|> (symbol "-" >> operatorLabel operator_minus) <|> (symbol "*" >> operatorLabel operator_star) <|> (symbol "/" >> operatorLabel operator_slash) <?> "" -- subject = node subject :: N3Parser RDFLabel subject = node -- object = litNode -- -- This production adds a new triple to the graph state, -- using the supplied subject and property values. -- If swap is True, the subject and object positions are -- swapped. object :: RDFLabel -> RDFLabel -> Bool -> N3Parser () object subj ppty True = do o <- litNode addStatement o ppty subj object subj ppty _ = do o <- litNode addStatement subj ppty o -- nodeList = litNode* -- -- subj is the node from which the list is linked. -- -- Returns the supplied head of list or Nil node allocated. -- -- Link first element of link to list head, scan rest of list, -- and return the list head; otherwise return a node rdf_null. -- -- This slightly convoluted pattern is to deal with two different -- occurrences of a list node: -- <node> :- ( l1, l2, ... ) -- Here, <node> (the supplied subj) is the listhead. -- <node> prop ( l1, l2, ... ) -- Here, the a new blank is supplied as subj to be the listhead. -- In either case, if the list is non-empty, the supplied subj -- is returned. But if the list is empty, a rdf_null node is returned. -- In the second case, the invoking production must use the returned -- value. nodeList :: RDFLabel -> N3Parser RDFLabel nodeList subj = (do val <- litNode first <- operatorLabel rdf_first addStatement subj first val nodeList1 subj return subj) <|> operatorLabel rdf_nil <?> "Node or ')'" nodeList1 :: RDFLabel -> N3Parser () nodeList1 prev = (do val <- litNode lnk <- newBlankNode first <- operatorLabel rdf_first rest <- operatorLabel rdf_rest addStatement lnk first val addStatement prev rest lnk nodeList1 lnk) <|> (do nil <- operatorLabel rdf_nil rest <- operatorLabel rdf_rest addStatement prev rest nil) <?> "Node or ')'" -- lit-node = node -- | str-node [ "@" lang ] [ "^^" uriRef2 ] -- str-node = '"' constant-value '"' -- | '"""' constant value '"""' // Including single or double occurences of -- // quotes and/or newlines -- -- Returns a new node value. litNode :: N3Parser RDFLabel litNode = node <|> liftM2 Lit strNode litTypeOrLang <?> "URI, blank node or literal" strNode :: N3Parser String strNode = tripleQuoteString <|> singleQuoteString litTypeOrLang :: N3Parser (Maybe ScopedName) litTypeOrLang = langTag <|> typeUri <|> return Nothing <?> "'@tag' (language tag) or '^^name' (datatype URI)" langTag :: N3Parser (Maybe ScopedName) langTag = fmap (Just . langName) (string "@" >> name) <?> "'@tag' (language tag)" typeUri :: N3Parser (Maybe ScopedName) typeUri = fmap Just (string "^^" >> uriRef2) <?> "'^^name' (datatype URI)" -- node = nodeid -- | varid -- | uri-ref2 -- | anon-node -- -- nodeid = "_:" name -- -- varid = "?" name -- -- Returns a new node value. node :: N3Parser RDFLabel node = nodeid <|> varid <|> uriNode <|> (newBlankNode >>= anonNode) <?> "URI or blank node" -- Identified blank node in input -- -- Note that automatically generated blank node identifiers start with -- a digit, where input node identifiers start with a letter, so there -- can be no clash. Care is needed when serializing a graph to ensure -- that future clashes are avoided. nodeid :: N3Parser RDFLabel -- nodeid = lexeme nodeid1 nodeid = fmap Blank (string "_:" >> name) -- variable identifier varid :: N3Parser RDFLabel varid = fmap Var (string "?" >> name) -- uriNode = qname -- | "<" URI-reference ">" -- | "this" uriNode :: N3Parser RDFLabel uriNode = fmap Res uriRef2 <|> fmap thisNode (string "this" >> getState) <?> "URI node" -- uriRef2 = qname -- | ":" local-name -- | "<" URI-reference ">" -- qname = prefix ":" local-name -- -- prefix = name // Namespace prefix -- -- local-name = name // Local name (namespace qualified) -- -- name = alpha alphanumeric* -- -- alpha = "a"-"z" -- | "A"-"Z" -- | "_" -- -- alphanumeric = alpha -- | "0"-"9" -- -- URI-reference = (conforming to syntax in RFC2396) -- -- uriRef2 returns a ScopedName. uriRef2 :: N3Parser ScopedName uriRef2 = lexeme (try uriRef2a) <?> "URI or QName" uriRef2a :: N3Parser ScopedName uriRef2a = liftM2 ScopedName prefix (colon >> localname) <|> (colon >> liftM2 ScopedName defaultprefix localname) <|> fmap makeUriScopedName absUriRef <?> "URI or QName" prefix :: N3Parser Namespace prefix = do pref <- prefixname st <- getState return (getPrefixNs st pref) -- map prefix to namespace defaultprefix :: N3Parser Namespace defaultprefix = do st <- getState return (getPrefixNs st "") name :: N3Parser String name = lexeme $ name1 identStart prefixname :: N3Parser String prefixname = name1 identStart localname :: N3Parser String localname = lexeme $ name1 identLetter -- 'name1' is a name without following whitespace -- initChar is a parser for the first character name1 :: N3Parser Char -> N3Parser String name1 initChar = liftM2 (:) initChar (many identLetter) <?> "identifier" ---------------------------------------------------------------------- -- Lexical support ---------------------------------------------------------------------- -- -- The following code adapted from ParsecToken, -- modified to handle different escape conventions and triple-quoted strings -- \c -- \uhhhh -- \Uhhhhhhhh -- -- Regular single-quoted string -- cannot be split over line breaks singleQuoteString :: N3Parser String singleQuoteString = lexeme ( between (char '"') (char '"' <?> "end of string (\")") anyStringChars <?> "literal string" ) anyStringChars :: CharParser st String anyStringChars = fmap (foldr (maybe id (:)) "") (many stringChar) -- Triple-quoted string -- may include line breaks, '"' or '""'. tripleQuoteString :: N3Parser String tripleQuoteString = lexeme (fmap (foldr (++) "") $ between (try $ string "\"\"\"") (string "\"\"\"" <?> "end of string (\"\"\")") (many tripleQuoteSubstring)) <?> "triple-quoted literal string" -- Match non-quote substring or one or two quote characters tripleQuoteSubstring :: N3Parser String tripleQuoteSubstring = tripleQuoteSubstring1 <|> try sqTripleQuoteSubstring1 <|> try dqTripleQuoteSubstring1 dqTripleQuoteSubstring1 :: N3Parser String dqTripleQuoteSubstring1 = fmap ("\"\""++) $ string "\"\"" >> tripleQuoteSubstring1 sqTripleQuoteSubstring1 :: N3Parser String sqTripleQuoteSubstring1 = fmap ('"':) $ char '"' >> tripleQuoteSubstring1 -- match at least one non-quote character in a triple-quoted string tripleQuoteSubstring1 :: N3Parser String tripleQuoteSubstring1 = fmap (foldr (maybe id (:)) "") $ many1 tripleQuoteStringChar tripleQuoteStringChar :: CharParser st (Maybe Char) tripleQuoteStringChar = stringChar <|> (string "\n" >> return (Just '\n')) stringChar :: CharParser st (Maybe Char) stringChar = fmap Just stringLetter <|> stringEscape <?> "string character" stringLetter :: CharParser st Char stringLetter = satisfy (\c -> (c /= '"') && (c /= '\\') && (c >= '\032')) stringEscape :: CharParser st (Maybe Char) stringEscape = fmap Just $ char '\\' >> escapeCode -- escape codes escapeCode :: CharParser st Char escapeCode = charEsc <|> charUCS2 <|> charUCS4 <?> "escape code" -- \c charEsc :: CharParser st Char charEsc = choice (map parseEsc escMap) where parseEsc (c,code) = fmap (const code) (char c) escMap = zip "nrt\\\"\'" "\n\r\t\\\"\'" -- \uhhhh charUCS2 :: CharParser st Char charUCS2 = fmap chr $ char 'u' >> numberFW 16 hexDigit 4 0 -- \Uhhhhhhhh charUCS4 :: CharParser st Char charUCS4 = fmap chr $ char 'U' >> numberFW 16 hexDigit 8 0 -- parse fixed-width number: numberFW :: Int -> CharParser st Char -> Int -> Int -> CharParser st Int numberFW _ _ 0 val = return val numberFW base baseDigit width val = do d <- baseDigit numberFW base baseDigit (width-1) (val*base + digitToInt d) ---------------------------------------------------------------------- -- Parse a URI reference from the input -- The result returned has absolute form; relative URIs are resolved -- relative to the current base prefix (set using "@base"). -- -- lexeme version lexUriRef :: N3Parser String lexUriRef = lexeme absUriRef -- from Swish.Utils.ProcessURI absoluteUriPart :: String -- ^ URI base -> String -- ^ URI reference -> String absoluteUriPart base rel = showURI $ fromJust $ relativeTo (fromJust (parseURIReference rel)) (fromJust (parseURI base)) absUriRef :: N3Parser String absUriRef = do u <- between (char '<') (char '>' <?> "end of URI '>'") anyUriChars if isURI u then return u else if isURIReference u then do s <- getState return $ absoluteUriPart (getSUri s "base") u else fail ("Invalid URI: <"++u++">") anyUriChars :: N3Parser String anyUriChars = many uriChar uriChar :: N3Parser Char uriChar = alphaNum <|> oneOf "[];?:@&=+$,-_.!~*'()%//#" <?> "URI character" -} -------------------------------------------------------------------------------- -- -- Copyright (c) 2003, Graham Klyne, 2009 Vasili I Galchin, 2011 Douglas Burke -- All rights reserved. -- -- This file is part of Swish. -- -- Swish is free software; you can redistribute it and/or modify -- it under the terms of the GNU General Public License as published by -- the Free Software Foundation; either version 2 of the License, or -- (at your option) any later version. -- -- Swish is distributed in the hope that it will be useful, -- but WITHOUT ANY WARRANTY; without even the implied warranty of -- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the -- GNU General Public License for more details. -- -- You should have received a copy of the GNU General Public License -- along with Swish; if not, write to: -- The Free Software Foundation, Inc., -- 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA -- --------------------------------------------------------------------------------