Safe Haskell | None |
---|---|
Language | Haskell98 |
- data LValue
- data Node
- type Subject = Node
- type Predicate = Node
- type Object = Node
- data Triple = Triple !Node !Node !Node
- type Triples = [Triple]
- class View a b where
- plainL :: Text -> LValue
- plainLL :: Text -> Text -> LValue
- typedL :: Text -> Text -> LValue
- unode :: Text -> Node
- bnode :: Text -> Node
- lnode :: LValue -> Node
- triple :: Subject -> Predicate -> Object -> Triple
- unodeValidate :: Text -> Maybe Node
- uriValidate :: Text -> Maybe Text
- uriValidateString :: String -> Maybe String
- isUNode :: Node -> Bool
- isLNode :: Node -> Bool
- isBNode :: Node -> Bool
- resolveQName :: Maybe BaseUrl -> Text -> PrefixMappings -> Maybe Text
- absolutizeUrl :: Maybe BaseUrl -> Maybe Text -> Text -> Text
- isAbsoluteUri :: Text -> Bool
- mkAbsoluteUrl :: Text -> Text -> Text
- escapeRDFSyntax :: Text -> Text
- fileSchemeToFilePath :: Node -> Maybe Text
- class RDF rdf where
- class RdfParser p where
- class RdfSerializer s where
- data Namespace
- newtype PrefixMappings = PrefixMappings (Map Text Text)
- newtype PrefixMapping = PrefixMapping (Text, Text)
- newtype BaseUrl = BaseUrl Text
- type NodeSelector = Maybe (Node -> Bool)
- newtype ParseFailure = ParseFailure String
RDF triples, nodes and literals
PlainL !Text | A plain (untyped) literal value in an unspecified language. |
PlainLL !Text !Text | A plain (untyped) literal value with a language specifier. |
TypedL !Text !Text | A typed literal value consisting of the literal value and the URI of the datatype of the value, respectively. |
Eq LValue Source # | Two |
Ord LValue Source # | Ordering of |
Show LValue Source # | |
Generic LValue Source # | |
Binary LValue Source # | |
NFData LValue Source # | |
Hashable LValue Source # | |
type Rep LValue Source # | |
An RDF node, which may be either a URIRef node (UNode
), a blank
node (BNode
), or a literal node (LNode
).
UNode !Text | An RDF URI reference. URIs conform to the RFC3986 standard. See http://www.w3.org/TR/rdf-concepts/#section-Graph-URIref for more information. |
BNode !Text | An RDF blank node. See http://www.w3.org/TR/rdf-concepts/#section-blank-nodes for more information. |
BNodeGen !Int | An RDF blank node with an auto-generated identifier, as used in Turtle. |
LNode !LValue | An RDF literal. See http://www.w3.org/TR/rdf-concepts/#section-Graph-Literal for more information. |
Eq Node Source # | A node is equal to another node if they are both the same type of node and if the field values are equal. |
Ord Node Source # | Node ordering is defined first by type, with Unode < BNode < BNodeGen < LNode PlainL < LNode PlainLL < LNode TypedL, and secondly by the natural ordering of the node value. E.g., a '(UNode _)' is LT any other type of node, and a '(LNode (TypedL _ _))' is GT any other type of node, and the ordering of '(BNodeGen 44)' and '(BNodeGen 3)' is that of the values, or 'compare 44 3', GT. |
Show Node Source # | |
Generic Node Source # | |
Binary Node Source # | |
NFData Node Source # | |
Hashable Node Source # | |
type Rep Node Source # | |
An RDF triple is a statement consisting of a subject, predicate, and object, respectively.
See http://www.w3.org/TR/rdf-concepts/#section-triples for more information.
Eq Triple Source # | Two triples are equal iff their respective subjects, predicates, and objects are equal. |
Ord Triple Source # | The ordering of triples is based on that of the subject, predicate, and object of the triple, in that order. |
Show Triple Source # | |
Generic Triple Source # | |
Binary Triple Source # | |
NFData Triple Source # | |
type Rep Triple Source # | |
A type class for ADTs that expose views to clients.
Constructor functions
plainLL :: Text -> Text -> LValue Source #
Return a PlainLL LValue for the given string value and language, respectively.
typedL :: Text -> Text -> LValue Source #
Return a TypedL LValue for the given string value and datatype URI, respectively.
uriValidate :: Text -> Maybe Text Source #
Validate a Text URI and return it in a Just Text
if it is
valid, otherwise Nothing
is returned. See unodeValidate
.
uriValidateString :: String -> Maybe String Source #
Same as uriValidate
, but on String
rather than Text
Node query function
Miscellaneous
resolveQName :: Maybe BaseUrl -> Text -> PrefixMappings -> Maybe Text Source #
Resolve a prefix using the given prefix mappings and base URL. If the prefix is empty, then the base URL will be used if there is a base URL and if the map does not contain an entry for the empty prefix.
absolutizeUrl :: Maybe BaseUrl -> Maybe Text -> Text -> Text Source #
Resolve a URL fragment found on the right side of a prefix mapping by converting it to an absolute URL if possible.
isAbsoluteUri :: Text -> Bool Source #
returns True
if URI is absolute.
mkAbsoluteUrl :: Text -> Text -> Text Source #
Make an absolute URL by returning as is if already an absolute URL and otherwise appending the URL to the given base URL.
escapeRDFSyntax :: Text -> Text Source #
Escapes Uxxxxxxxx
and uxxxx
character sequences according
to the RDF specification.
fileSchemeToFilePath :: Node -> Maybe Text Source #
Removes "file://" schema from URIs in UNode
nodes
RDF Type
An RDF value is a set of (unique) RDF triples, together with the operations defined upon them.
For information about the efficiency of the functions, see the documentation for the particular RDF instance.
For more information about the concept of an RDF graph, see the following: http://www.w3.org/TR/rdf-concepts/#section-rdf-graph.
baseUrl :: rdf -> Maybe BaseUrl Source #
Return the base URL of this RDF, if any.
prefixMappings :: rdf -> PrefixMappings Source #
Return the prefix mappings defined for this RDF, if any.
addPrefixMappings :: rdf -> PrefixMappings -> Bool -> rdf Source #
Return an RDF with the specified prefix mappings merged with the existing mappings. If the Bool arg is True, then a new mapping for an existing prefix will replace the old mapping; otherwise, the new mapping is ignored.
Return an empty RDF.
mkRdf :: Triples -> Maybe BaseUrl -> PrefixMappings -> rdf Source #
Return a RDF containing all the given triples. Handling of duplicates in the input depend on the particular RDF implementation.
triplesOf :: rdf -> Triples Source #
Return all triples in the RDF, as a list.
Note that this function returns a list of triples in the RDF as they were added, without removing duplicates and without expanding namespaces.
uniqTriplesOf :: rdf -> Triples Source #
Return unique triples in the RDF, as a list.
This function performs namespace expansion and removal of duplicates.
select :: rdf -> NodeSelector -> NodeSelector -> NodeSelector -> Triples Source #
Select the triples in the RDF that match the given selectors.
The three NodeSelector parameters are optional functions that match
the respective subject, predicate, and object of a triple. The triples
returned are those in the given graph for which the first selector
returns true when called on the subject, the second selector returns
true when called on the predicate, and the third selector returns true
when called on the ojbect. A Nothing
parameter is equivalent to a
function that always returns true for the appropriate node; but
implementations may be able to much more efficiently answer a select
that involves a Nothing
parameter rather than an (id True)
parameter.
The following call illustrates the use of select, and would result in the selection of all and only the triples that have a blank node as subject and a literal node as object:
select gr (Just isBNode) Nothing (Just isLNode)
Note: this function may be very slow; see the documentation for the particular RDF implementation for more information.
query :: rdf -> Maybe Node -> Maybe Node -> Maybe Node -> Triples Source #
Return the triples in the RDF that match the given pattern, where the pattern (3 Maybe Node parameters) is interpreted as a triple pattern.
The Maybe Node
params are interpreted as the subject, predicate, and
object of a triple, respectively. Just n
is true iff the triple has
a node equal to n
in the appropriate location; Nothing
is always
true, regardless of the node in the appropriate location.
For example, query rdf (Just n1) Nothing (Just n2)
would return all
and only the triples that have n1
as subject and n2
as object,
regardless of the predicate of the triple.
Parsing RDF
class RdfParser p where Source #
An RdfParser is a parser that knows how to parse 1 format of RDF and can parse an RDF document of that type from a string, a file, or a URL. Required configuration options will vary from instance to instance.
parseString :: forall rdf. RDF rdf => p -> Text -> Either ParseFailure rdf Source #
Parse RDF from the given text, yielding a failure with error message or the resultant RDF.
parseFile :: forall rdf. RDF rdf => p -> String -> IO (Either ParseFailure rdf) Source #
Parse RDF from the local file with the given path, yielding a failure with error message or the resultant RDF in the IO monad.
parseURL :: forall rdf. RDF rdf => p -> String -> IO (Either ParseFailure rdf) Source #
Parse RDF from the remote file with the given HTTP URL (https is not supported), yielding a failure with error message or the resultant graph in the IO monad.
RdfParser NTriplesParser Source # |
|
RdfParser XmlParser Source # | |
RdfParser TurtleParser Source # |
|
Serializing RDF
class RdfSerializer s where Source #
An RdfSerializer is a serializer of RDF to some particular output format, such as NTriples or Turtle.
hWriteRdf :: forall rdf. RDF rdf => s -> Handle -> rdf -> IO () Source #
Write the RDF to a file handle using whatever configuration is specified by the first argument.
writeRdf :: forall rdf. RDF rdf => s -> rdf -> IO () Source #
Write the RDF to stdout; equivalent to
.hWriteRdf
stdout
hWriteH :: forall rdf. RDF rdf => s -> Handle -> rdf -> IO () Source #
Write to the file handle whatever header information is required based on the output format. For example, if serializing to Turtle, this method would write the necessary @prefix declarations and possibly a @baseUrl declaration, whereas for NTriples, there is no header section at all, so this would be a no-op.
writeH :: forall rdf. RDF rdf => s -> rdf -> IO () Source #
Write header information to stdout; equivalent to
.hWriteRdf
stdout
hWriteTs :: s -> Handle -> Triples -> IO () Source #
Write some triples to a file handle using whatever configuration is specified by the first argument.
WARNING: if the serialization format has header-level information
that should be output (e.g., @prefix declarations for Turtle), then you should
use hWriteG
instead of this method unless you're sure this is safe to use, since
otherwise the resultant document will be missing the header information and
will not be valid.
writeTs :: s -> Triples -> IO () Source #
Write some triples to stdout; equivalent to
.hWriteTs
stdout
hWriteT :: s -> Handle -> Triple -> IO () Source #
Write a single triple to the file handle using whatever configuration is
specified by the first argument. The same WARNING applies as to hWriteTs
.
writeT :: s -> Triple -> IO () Source #
Write a single triple to stdout; equivalent to
.hWriteT
stdout
hWriteN :: s -> Handle -> Node -> IO () Source #
Write a single node to the file handle using whatever configuration is
specified by the first argument. The same WARNING applies as to hWriteTs
.
writeN :: s -> Node -> IO () Source #
Write a single node to sdout; equivalent to
.hWriteN
stdout
Namespaces and Prefixes
Represents a namespace as either a prefix and uri, respectively, or just a uri.
newtype PrefixMappings Source #
An alias for a map from prefix to namespace URI.
newtype PrefixMapping Source #
A mapping of a prefix to the URI for that prefix.
Supporting types
The base URL of an RDF.
type NodeSelector = Maybe (Node -> Bool) Source #
A NodeSelector
is either a function that returns True
or False
for a node, or Nothing, which indicates that all
nodes would return True
.
The selector is said to select, or match, the nodes for
which it returns True
.
When used in conjunction with the select
method of Graph
, three
node selectors are used to match a triple.
newtype ParseFailure Source #
Represents a failure in parsing an N-Triples document, including an error message with information about the cause for the failure.