RDF.Description (RDF.ex v0.9.4) View Source

A set of RDF triples about the same subject.

RDF.Description implements:

Link to this section Summary

Functions

Changes the subject of a description.

Deletes all statements with the given properties.

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

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 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.

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.

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

Link to this section Types

Link to this section Functions

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

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Specs

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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change_subject(description, new_subject)

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Specs

change_subject(t(), RDF.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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Specs

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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Specs

Deletes all statements with the given properties.

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describes?(description, other_subject)

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Specs

describes?(t(), RDF.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
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equal?(description1, description2)

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Specs

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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Specs

fetch(t(), RDF.Statement.coercible_predicate()) ::
  {:ok, [RDF.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)

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Specs

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
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get(description, predicate, default \\ nil)

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Specs

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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Specs

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

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

Checks if the given input statements exist within description.

Specs

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 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.

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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Specs

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)

Specs

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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Specs

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

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

Specs

pop(t()) :: {RDF.Triple.t() | [RDF.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.

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.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})}

Specs

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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Specs

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 more strict 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})

Specs

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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Specs

statement_count(t()) :: non_neg_integer()

Returns the number of statements of a RDF.Description.

See RDF.Description.triples/1.

Specs

subject(t()) :: RDF.Statement.subject()

Returns the subject IRI or blank node of a description.

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take(description, predicates)

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Specs

take(t(), [RDF.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.

Specs

triples(t()) :: keyword()

The list of all triples within a RDF.Description.

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

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Specs

update(
  t(),
  RDF.Statement.coercible_predicate(),
  RDF.Statement.coercible_object() | nil,
  ([RDF.Statement.Object] -> [RDF.Statement.Object])
) :: t()

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 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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values(description, opts \\ [])

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Specs

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 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.

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"]}