View Source RDF.Triple (RDF.ex v2.0.1)

Helper functions for RDF triples.

An RDF Triple is represented as a plain Elixir tuple consisting of three valid RDF values for subject, predicate and object.

Summary

Functions

Returns a list of all RDF.BlankNodes within the given triple.

Returns whether the given triple contains a blank node.

Returns whether the given value is a component of the given triple.

Returns a triple where each element from a RDF.Triple is mapped with the given function.

Creates a RDF.Triple with proper RDF values.

Checks if the given tuple is a valid RDF triple.

Returns a tuple of native Elixir values from a RDF.Triple of RDF terms.

Types

Functions

@spec bnodes(t()) :: [RDF.BlankNode.t()]

Returns a list of all RDF.BlankNodes within the given triple.

@spec has_bnode?(t()) :: boolean()

Returns whether the given triple contains a blank node.

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include_value?(arg, value)

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@spec include_value?(t(), any()) :: boolean()

Returns whether the given value is a component of the given triple.

@spec map(t(), RDF.Statement.term_mapping()) :: mapping_value() | nil

Returns a triple where each element from a RDF.Triple is mapped with the given function.

Returns nil if one of the components of the given tuple is not convertible via RDF.Term.value/1.

The function fun will receive a tuple {statement_position, rdf_term} where statement_position is one of the atoms :subject, :predicate or :object, while rdf_term is the RDF term to be mapped. When the given function returns nil this will be interpreted as an error and will become the overhaul result of the map/2 call.

Examples

iex> {~I<http://example.com/S>, ~I<http://example.com/p>, RDF.literal(42)}
...> |> RDF.Triple.map(fn
...>      {:object, object} -> RDF.Term.value(object)
...>      {_, term}         -> term |> to_string() |> String.last()
...>    end)
{"S", "p", 42}
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new(statement, property_map \\ nil)

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@spec new(RDF.Statement.coercible(), RDF.PropertyMap.t() | nil) :: t()

Creates a RDF.Triple with proper RDF values.

An error is raised when the given elements are not coercible to RDF values.

Note: The RDF.triple function is a shortcut to this function.

Examples

iex> RDF.Triple.new {"http://example.com/S", "http://example.com/p", 42}
{~I<http://example.com/S>, ~I<http://example.com/p>, RDF.literal(42)}

iex> RDF.Triple.new {EX.S, EX.p, 42}
{RDF.iri("http://example.com/S"), RDF.iri("http://example.com/p"), RDF.literal(42)}

iex> RDF.Triple.new {EX.S, EX.p, 42, EX.Graph}
{RDF.iri("http://example.com/S"), RDF.iri("http://example.com/p"), RDF.literal(42)}

iex> RDF.Triple.new {EX.S, :p, 42}, RDF.PropertyMap.new(p: EX.p)
{RDF.iri("http://example.com/S"), RDF.iri("http://example.com/p"), RDF.literal(42)}
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new(subject, predicate, object, property_map \\ nil)

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Creates a RDF.Triple with proper RDF values.

An error is raised when the given elements are not coercible to RDF values.

Note: The RDF.triple function is a shortcut to this function.

Examples

iex> RDF.Triple.new("http://example.com/S", "http://example.com/p", 42)
{~I<http://example.com/S>, ~I<http://example.com/p>, RDF.literal(42)}

iex> RDF.Triple.new(EX.S, EX.p, 42)
{RDF.iri("http://example.com/S"), RDF.iri("http://example.com/p"), RDF.literal(42)}

iex> RDF.Triple.new(EX.S, :p, 42, RDF.PropertyMap.new(p: EX.p))
{RDF.iri("http://example.com/S"), RDF.iri("http://example.com/p"), RDF.literal(42)}
@spec valid?(t() | any()) :: boolean()

Checks if the given tuple is a valid RDF triple.

The elements of a valid RDF triple must be RDF terms. On the subject position only IRIs and blank nodes allowed, while on the predicate position only IRIs allowed. The object position can be any RDF term.

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values(triple, opts \\ [])

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@spec values(
  t(),
  keyword()
) :: mapping_value() | nil

Returns a tuple of native Elixir values from a RDF.Triple of RDF terms.

When a :context option is given with a RDF.PropertyMap, predicates will be mapped to the terms defined in the RDF.PropertyMap, if present.

Returns nil if one of the components of the given tuple is not convertible via RDF.Term.value/1.

Examples

iex> RDF.Triple.values {~I<http://example.com/S>, ~I<http://example.com/p>, RDF.literal(42)}
{"http://example.com/S", "http://example.com/p", 42}

iex> {~I<http://example.com/S>, ~I<http://example.com/p>, RDF.literal(42)}
...> |> RDF.Triple.values(context: %{p: ~I<http://example.com/p>})
{"http://example.com/S", :p, 42}