View Source RDF.Quad (RDF.ex v0.11.0)

Helper functions for RDF quads.

An RDF Quad is represented as a plain Elixir tuple consisting of four valid RDF values for subject, predicate, object and a graph name.

Link to this section Summary

Functions

Returns a tuple where each element from a RDF.Quad is mapped with the given function.

Creates a RDF.Quad with proper RDF values.

Checks if the given tuple is a valid RDF quad.

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

Link to this section Types

Link to this section Functions

Specs

Returns a tuple where each element from a RDF.Quad 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, :object or :graph_name 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

Examples

iex> {~I<http://example.com/S>, ~I<http://example.com/p>, RDF.literal(42), ~I<http://example.com/Graph>}
...> |> RDF.Quad.map(fn
...>      {:object, object} ->
...>        RDF.Term.value(object)
...>      {:graph_name, graph_name} ->
...>        graph_name
...>      {_, resource} ->
...>        resource |> to_string() |> String.last() |> String.to_atom()
...>    end)
{:S, :p, 42, ~I<http://example.com/Graph>}
Link to this function

new(statement, property_map \\ nil)

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Specs

Creates a RDF.Quad with proper RDF values.

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

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

examples

Examples

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

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

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

iex> RDF.Quad.new {EX.S, :p, 42, EX.Graph}, RDF.PropertyMap.new(p: EX.p)
{RDF.iri("http://example.com/S"), RDF.iri("http://example.com/p"), RDF.literal(42), RDF.iri("http://example.com/Graph")}
Link to this function

new(subject, predicate, object, graph_name, property_map \\ nil)

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Specs

Creates a RDF.Quad with proper RDF values.

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

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

examples

Examples

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

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

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

Specs

valid?(t() | any()) :: boolean()

Checks if the given tuple is a valid RDF quad.

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

Link to this function

values(quad, opts \\ [])

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Specs

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

Returns a tuple of native Elixir values from a RDF.Quad 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

Examples

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

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