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

A set of RDF triples about the same subject.

RDF.Description implements:

Summary

Functions

Returns a hash of the canonical form of the given description.

Changes the subject of a description.

Deletes all statements with the given properties.

Checks if a RDF.Description has the given resource as subject.

Returns if the given description is empty.

Fetches the objects for the given predicate of a Description.

Gets a single object for the given predicate of a Description.

Gets the objects for the given predicate of a Description.

Gets and updates the objects of the given predicate of a Description, in a single pass.

Checks if the given input statements exist within description.

Returns a new description that is the intersection of the given description with the given data.

Returns a map of a RDF.Description where each element from its triples is mapped with the given function.

Creates an RDF.Description about the given subject.

The set of all resources used in the objects within a RDF.Description.

The set of all resources used in the objects within a RDF.Description satisfying the given filter criterion.

Pops an arbitrary triple from a RDF.Description.

Pops the objects of the given predicate of a Description.

The set of all properties used in the predicates within a RDF.Description.

Adds statements to a RDF.Description and overwrites all existing statements with already used predicates.

Replaces all occurrences of old_id in description with new_id.

The set of all resources used within a RDF.Description.

Returns the number of statements of a RDF.Description.

Returns the subject IRI or blank node of a description.

Creates a description from another one by limiting its statements to those using one of the given predicates.

The list of all triples within a RDF.Description.

Updates the objects of the predicate in description with the given function.

Updates all objects in description with the given function.

Updates all predications in description with the given function.

Returns a map of the native Elixir values of a RDF.Description.

Removes all objects from a description which are quoted triples.

Types

Functions

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add(description, input, opts \\ [])

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@spec add(t(), input(), keyword()) :: t()

Add statements to a RDF.Description.

Note: When the statements to be added are given as another RDF.Description, the subject must not match subject of the description to which the statements are added. As opposed to that RDF.Data.merge/2 will produce a RDF.Graph containing both descriptions.

Examples

iex> RDF.Description.new(EX.S, init: {EX.P1, EX.O1})
...> |> RDF.Description.add({EX.P2, EX.O2})
RDF.Description.new(EX.S, init: [{EX.P1, EX.O1}, {EX.P2, EX.O2}])

iex> RDF.Description.new(EX.S, init: {EX.P, EX.O1})
...> |> RDF.Description.add({EX.P, [EX.O2, EX.O3]})
RDF.Description.new(EX.S, init: [{EX.P, EX.O1}, {EX.P, EX.O2}, {EX.P, EX.O3}])
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canonical_hash(description, opts \\ [])

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@spec canonical_hash(
  t(),
  keyword()
) :: binary()

Returns a hash of the canonical form of the given description.

See RDF.Dataset.canonical_hash/2 for more information.

Example

iex> RDF.Description.new(EX.S, init: {EX.p(), EX.O})
...> |> RDF.Description.canonical_hash()
"4a883e60f7b38b89b72492f16114ea62cf9a21d0e232d066b1f59ef61c69ea12"
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change_subject(description, new_subject)

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@spec change_subject(t(), RDF.Star.Statement.coercible_subject()) :: t()

Changes the subject of a description.

See RDF.Description.statement_count/1.

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delete(description, input, opts \\ [])

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@spec delete(t(), input(), keyword()) :: t()

Deletes statements from a RDF.Description.

Note: When the statements to be deleted are given as another RDF.Description, the subject must not match subject of the description from which the statements are deleted. If you want to delete only a matching description subject, you can use RDF.Data.delete/2.

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delete_predicates(description, properties)

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Deletes all statements with the given properties.

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describes?(description, other_subject)

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@spec describes?(t(), RDF.Star.Statement.subject()) :: boolean()

Checks if a RDF.Description has the given resource as subject.

Examples

  iex> RDF.Description.new(EX.S1, init: {EX.p1, EX.O1})
  ...> |> RDF.Description.describes?(EX.S1)
  true
  iex> RDF.Description.new(EX.S1, init: {EX.p1, EX.O1})
  ...> |> RDF.Description.describes?(EX.S2)
  false
@spec empty?(t()) :: boolean()

Returns if the given description is empty.

Note: You should always prefer this over the use of Enum.empty?/1 as it is significantly faster.

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equal?(description1, description2)

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@spec equal?(t(), t()) :: boolean()

Checks if two RDF.Descriptions are equal.

Two RDF.Descriptions are considered to be equal if they contain the same triples.

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fetch(description, predicate)

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@spec fetch(t(), RDF.Star.Statement.coercible_predicate()) ::
  {:ok, [RDF.Star.Statement.object()]} | :error

Fetches the objects for the given predicate of a Description.

When the predicate can not be found :error is returned.

Examples

iex> RDF.Description.new(EX.S, init: {EX.p, EX.O}) |> RDF.Description.fetch(EX.p)
{:ok, [RDF.iri(EX.O)]}
iex> RDF.Description.new(EX.S, init: [{EX.P, EX.O1}, {EX.P, EX.O2}])
...> |> RDF.Description.fetch(EX.P)
{:ok, [RDF.iri(EX.O1), RDF.iri(EX.O2)]}
iex> RDF.Description.new(EX.S) |> RDF.Description.fetch(EX.foo)
:error
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first(description, predicate, default \\ nil)

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Gets a single object for the given predicate of a Description.

When the predicate can not be found, the optionally given default value or nil is returned.

Examples

iex> RDF.Description.new(EX.S, init: {EX.P, EX.O}) |> RDF.Description.first(EX.P)
RDF.iri(EX.O)
iex> RDF.Description.new(EX.S) |> RDF.Description.first(EX.foo)
nil
iex> RDF.Description.new(EX.S) |> RDF.Description.first(EX.foo, :bar)
:bar
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get(description, predicate, default \\ nil)

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Gets the objects for the given predicate of a Description.

When the predicate can not be found, the optionally given default value or nil is returned.

Examples

iex> RDF.Description.new(EX.S, init: {EX.P, EX.O}) |> RDF.Description.get(EX.P)
[RDF.iri(EX.O)]
iex> RDF.Description.new(EX.S) |> RDF.Description.get(EX.foo)
nil
iex> RDF.Description.new(EX.S) |> RDF.Description.get(EX.foo, :bar)
:bar
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get_and_update(description, predicate, fun)

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@spec get_and_update(
  t(),
  RDF.Star.Statement.coercible_predicate(),
  ([RDF.Star.Statement.Object] -> {[RDF.Star.Statement.Object], t()} | :pop)
) :: {[RDF.Star.Statement.Object], t()}

Gets and updates the objects of the given predicate of a Description, in a single pass.

Invokes the passed function on the objects of the given predicate; this function should return either {objects_to_return, new_object} or :pop.

If the passed function returns {objects_to_return, new_objects}, the return value of get_and_update is {objects_to_return, new_description} where new_description is the input Description updated with new_objects for the given predicate.

If the passed function returns :pop the objects for the given predicate are removed and a {removed_objects, new_description} tuple gets returned.

Examples

iex> RDF.Description.new(EX.S, init: {EX.P, EX.O})
...> |> RDF.Description.get_and_update(EX.P, fn current_objects ->
...>      {current_objects, EX.New}
...>    end)
{[RDF.iri(EX.O)], RDF.Description.new(EX.S, init: {EX.P, EX.New})}
iex> RDF.Graph.new([{EX.S, EX.P1, EX.O1}, {EX.S, EX.P2, EX.O2}])
...> |> RDF.Graph.description(EX.S)
...> |> RDF.Description.get_and_update(EX.P1, fn _ -> :pop end)
{[RDF.iri(EX.O1)], RDF.Description.new(EX.S, init: {EX.P2, EX.O2})}
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include?(description, input, opts \\ [])

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@spec include?(t(), input(), keyword()) :: boolean()

Checks if the given input statements exist within description.

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intersection(description, data)

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@spec intersection(t(), t() | RDF.Graph.t() | RDF.Dataset.t() | RDF.Graph.input()) ::
  t()

Returns a new description that is the intersection of the given description with the given data.

The data can be given in any form an RDF.Graph can be created from. When a RDF.Dataset is given, the aggregated description of the subject of description is used for the intersection.

Examples

iex> EX.S
...> |> EX.p(EX.O1, EX.O2)
...> |> RDF.Description.intersection(EX.S |> EX.p(EX.O2, EX.O3))
EX.S |> EX.p(EX.O2)

iex> EX.S
...> |> EX.p(EX.O1, EX.O2)
...> |> RDF.Description.intersection({EX.Other, EX.p, EX.O2, EX.O3})
RDF.Description.new(EX.S)
@spec map(t(), RDF.Star.Statement.term_mapping()) :: map()

Returns a map of a RDF.Description where each element from its triples is mapped with the given function.

The subject is not part of the result. If you want the subject in an outer map, just put the description in a graph and use RDF.Graph.map/2.

The function fun will receive a tuple {statement_position, rdf_term} where statement_position is one of the atoms :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.

Note: RDF-star statements where the object is a triple will be ignored.

Examples

iex> RDF.Description.new(~I<http://example.com/S>, init: {~I<http://example.com/p>, ~L"Foo"})
...> |> RDF.Description.map(fn
...>      {:predicate, predicate} ->
...>        predicate
...>        |> to_string()
...>        |> String.split("/")
...>        |> List.last()
...>        |> String.to_atom()
...>    {_, term} ->
...>      RDF.Term.value(term)
...>    end)
%{p: ["Foo"]}
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new(subject, opts \\ [])

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@spec new(
  RDF.Star.Statement.coercible_subject() | t(),
  keyword()
) :: t()

Creates an RDF.Description about the given subject.

The created RDF.Description can be initialized with any form of data which add/2 understands with the :init option. Additionally, a function returning the initialization data in any of these forms can be as the :init value.

Examples

RDF.Description.new(EX.S)
RDF.Description.new(EX.S, init: {EX.S, EX.p, EX.O})
RDF.Description.new(EX.S, init: {EX.p, [EX.O1, EX.O2]})
RDF.Description.new(EX.S, init: [{EX.p1, EX.O1}, {EX.p2, EX.O2}])
RDF.Description.new(EX.S, init: RDF.Description.new(EX.S, init: {EX.P, EX.O}))
RDF.Description.new(EX.S, init: fn -> {EX.p, EX.O} end)
@spec objects(t()) :: MapSet.t()

The set of all resources used in the objects within a RDF.Description.

Note: This function does collect only IRIs and BlankNodes, not Literals.

Examples

iex> RDF.Description.new(EX.S1, init: [
...>   {EX.p1, EX.O1},
...>   {EX.p2, EX.O2},
...>   {EX.p3, EX.O2},
...>   {EX.p4, RDF.bnode(:bnode)},
...>   {EX.p3, "foo"}])
...> |> RDF.Description.objects()
MapSet.new([RDF.iri(EX.O1), RDF.iri(EX.O2), RDF.bnode(:bnode)])
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objects(description, filter_fn)

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@spec objects(t(), (RDF.Star.Statement.object() -> boolean())) :: MapSet.t()

The set of all resources used in the objects within a RDF.Description satisfying the given filter criterion.

@spec pop(t()) :: {RDF.Star.Triple.t() | [RDF.Star.Statement.Object] | nil, t()}

Pops an arbitrary triple from a RDF.Description.

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pop(description, predicate)

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Pops the objects of the given predicate of a Description.

Removes the objects for the given predicate from description.

Returns a tuple containing a list the objects for the given predicate and the updated description without the respective statements. nil is returned instead of the objects if description does not contain any statements with the given predicate.

Examples

iex> RDF.Description.new(EX.S, init: {EX.P, EX.O})
...> |> RDF.Description.pop(EX.P)
{[RDF.iri(EX.O)], RDF.Description.new(EX.S)}

iex> RDF.Description.new(EX.S, init: {EX.P, EX.O})
...> |> RDF.Description.pop(EX.Missing)
{nil, RDF.Description.new(EX.S, init: {EX.P, EX.O})}
@spec predicates(t()) :: MapSet.t()

The set of all properties used in the predicates within a RDF.Description.

Examples

iex> RDF.Description.new(EX.S1, init: [
...>   {EX.p1, EX.O1},
...>   {EX.p2, EX.O2},
...>   {EX.p2, EX.O3}])
...> |> RDF.Description.predicates()
MapSet.new([EX.p1, EX.p2])
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put(description, input, opts \\ [])

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@spec put(t(), input(), keyword()) :: t()

Adds statements to a RDF.Description and overwrites all existing statements with already used predicates.

Note: As it is a destructive function this function is stricter in its handling of RDF.Descriptions than add/3. The subject of a RDF.Description to be put must match. If you want to overwrite existing statements with those from the description of another subject, you'll have to explicitly change the subject with change_subject/2 first before using put/3.

Examples

iex> RDF.Description.new(EX.S, init: {EX.P, EX.O1})
...> |> RDF.Description.put({EX.P, EX.O2})
RDF.Description.new(EX.S, init: {EX.P, EX.O2})
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rename_resource(description, old_id, old_id)

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@spec rename_resource(t(), RDF.Resource.coercible(), RDF.Resource.coercible()) :: t()

Replaces all occurrences of old_id in description with new_id.

@spec resources(t()) :: MapSet.t()

The set of all resources used within a RDF.Description.

Examples

iex> RDF.Description.new(EX.S1, init: [
...>   {EX.p1, EX.O1},
...>   {EX.p2, EX.O2},
...>   {EX.p1, EX.O2},
...>   {EX.p2, RDF.bnode(:bnode)},
...>   {EX.p3, "foo"}])
...> |> RDF.Description.resources()
MapSet.new([RDF.iri(EX.O1), RDF.iri(EX.O2), RDF.bnode(:bnode), EX.p1, EX.p2, EX.p3])
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statement_count(description)

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@spec statement_count(t()) :: non_neg_integer()

Returns the number of statements of a RDF.Description.

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statements(description, opts \\ [])

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See RDF.Description.triples/2.

@spec subject(t()) :: RDF.Star.Statement.subject()

Returns the subject IRI or blank node of a description.

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take(description, predicates)

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@spec take(t(), [RDF.Star.Statement.coercible_predicate()] | Enum.t() | nil) :: t()

Creates a description from another one by limiting its statements to those using one of the given predicates.

If predicates contains properties that are not used in the description, they're simply ignored.

If nil is passed, the description is left untouched.

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triples(description, opts \\ [])

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@spec triples(
  t(),
  keyword()
) :: [RDF.Star.Triple.t()]

The list of all triples within a RDF.Description.

When the optional :filter_star flag is set to true RDF-star triples with a triple as subject or object will be filtered. So, for a description with a triple as a subject you'll always get an empty list. The default value of the :filter_star flag is false.

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update(description, predicate, initial \\ nil, fun)

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Updates the objects of the predicate in description with the given function.

If predicate is present in description with objects as value, fun is invoked with argument objects and its result is used as the new list of objects of predicate. If predicate is not present in description, initial is inserted as the objects of predicate. The initial value will not be passed through the update function.

The initial value and the returned objects by the update function will be automatically coerced to proper RDF object values before added.

Examples

iex> RDF.Description.new(EX.S, init: {EX.p, EX.O})
...> |> RDF.Description.update(EX.p, fn objects -> [EX.O2 | objects] end)
RDF.Description.new(EX.S, init: [{EX.p, EX.O}, {EX.p, EX.O2}])
iex> RDF.Description.new(EX.S)
...> |> RDF.Description.update(EX.p, EX.O, fn _ -> EX.O2 end)
RDF.Description.new(EX.S, init: {EX.p, EX.O})
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update_all_objects(description, fun)

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Updates all objects in description with the given function.

fun is invoked for each object in description with the predicate and the object as two arguments. If nil is returned by fun, the respective object will be removed from description. The returned values by the update function will be coerced to proper RDF object values before added.

Examples

iex> EX.S |> EX.p1(1) |> EX.p2([2, 3])
...> |> RDF.Description.update_all_objects(fn _predicate, object ->
...>      RDF.XSD.Numeric.add(object, 1)
...>    end)
EX.S
|> EX.p1(2)
|> EX.p2([3, 4])
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update_all_predicates(description, fun)

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Updates all predications in description with the given function.

fun is invoked with a tuple {predicate, objects} for each predicate in description. If nil is returned by fun, the respective predications will be removed from description. The returned values by the update function will be coerced to proper RDF object values before added.

Examples

iex> EX.S |> EX.p1(1) |> EX.p2([2, 3])
...> |> RDF.Description.update_all_predicates(fn {_predicate, objects} -> ["foo" | objects] end)
EX.S
|> EX.p1([1, "foo"])
|> EX.p2([2, 3, "foo"])
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values(description, opts \\ [])

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@spec values(
  t(),
  keyword()
) :: map()

Returns a map of the native Elixir values of a RDF.Description.

The subject is not part of the result. It can be converted separately with RDF.Term.value/1, or, if you want the subject in an outer map, just put the description in a graph and use RDF.Graph.values/2.

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

Note: RDF-star statements where the object is a triple will be ignored.

Examples

iex> RDF.Description.new(~I<http://example.com/S>, init: {~I<http://example.com/p>, ~L"Foo"})
...> |> RDF.Description.values()
%{"http://example.com/p" => ["Foo"]}

iex> RDF.Description.new(~I<http://example.com/S>, init: {~I<http://example.com/p>, ~L"Foo"})
...> |> RDF.Description.values(context: %{p: ~I<http://example.com/p>})
%{p: ["Foo"]}
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without_quoted_triple_objects(description)

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@spec without_quoted_triple_objects(t()) :: t()

Removes all objects from a description which are quoted triples.