Add RDF.Dataset.prefixes/1

CHANGELOG.md

@@ -9,6 +9,7 @@ This project adheres to [Semantic Versioning](http://semver.org/) and
 
 ### Added
 
+- `RDF.Dataset.prefixes/1` for getting an aggregated `RDF.PrefixMap` over all graphs
 - `RDF.PrefixMap.put/3` for adding a prefix mapping and overwrite an existing one
  
 ### Changed

lib/rdf/blank_node/increment.ex

@@ -14,6 +14,12 @@ defmodule RDF.BlankNode.Increment do
 
   alias RDF.BlankNode
 
+  @type state :: %{
+          optional(:prefix) => String.t(),
+          map: map,
+          counter: pos_integer
+        }
+
   @impl BlankNode.Generator.Algorithm
   def init(%{prefix: prefix} = opts) do
     opts

lib/rdf/dataset.ex

@@ -17,7 +17,7 @@ defmodule RDF.Dataset do
 
   @behaviour Access
 
-  alias RDF.{Graph, Description, IRI, Statement, PropertyMap}
+  alias RDF.{Graph, Description, IRI, Statement, PrefixMap, PropertyMap}
   import RDF.Statement, only: [coerce_subject: 1, coerce_graph_name: 1]
   import RDF.Utils
 
@@ -853,6 +853,22 @@ defmodule RDF.Dataset do
 
   def equal?(_, _), do: false
 
+  @doc """
+  Returns the aggregated prefixes of all graphs of `dataset` as a `RDF.PrefixMap`.
+  """
+  @spec prefixes(t) :: PrefixMap.t() | nil
+  def prefixes(%__MODULE__{} = dataset) do
+    dataset
+    |> RDF.Dataset.graphs()
+    |> Enum.reduce(RDF.PrefixMap.new(), fn graph, prefixes ->
+      if graph.prefixes do
+        RDF.PrefixMap.merge!(prefixes, graph.prefixes, :ignore)
+      else
+        prefixes
+      end
+    end)
+  end
+
   defp clear_metadata(%__MODULE__{} = dataset) do
     %__MODULE__{
       dataset

lib/rdf/serializations/turtle_encoder.ex

@@ -4,7 +4,7 @@ defmodule RDF.Turtle.Encoder do
   use RDF.Serialization.Encoder
 
   alias RDF.Turtle.Encoder.State
-  alias RDF.{BlankNode, Dataset, Description, Graph, IRI, XSD, Literal, LangString}
+  alias RDF.{BlankNode, Dataset, Description, Graph, IRI, XSD, Literal, LangString, PrefixMap}
 
   @document_structure [
     :base,
@@ -36,14 +36,19 @@ defmodule RDF.Turtle.Encoder do
   @ordered_properties MapSet.new(@predicate_order)
 
   @impl RDF.Serialization.Encoder
-  @callback encode(Graph.t() | Dataset.t(), keyword | map) :: {:ok, String.t()} | {:error, any}
+  @spec encode(Graph.t() | Dataset.t(), keyword) :: {:ok, String.t()} | {:error, any}
   def encode(data, opts \\ []) do
-    with base =
-           Keyword.get(opts, :base, Keyword.get(opts, :base_iri))
-           |> base_iri(data)
-           |> init_base_iri(),
-         prefixes = Keyword.get(opts, :prefixes) |> prefixes(data) |> init_prefixes(),
-         {:ok, state} = State.start_link(data, base, prefixes) do
+    base =
+      Keyword.get(opts, :base, Keyword.get(opts, :base_iri))
+      |> base_iri(data)
+      |> init_base_iri()
+
+    prefixes =
+      Keyword.get(opts, :prefixes)
+      |> prefixes(data)
+      |> init_prefixes()
+
+    with {:ok, state} = State.start_link(data, base, prefixes) do
       try do
         State.preprocess(state)
 
@@ -74,7 +79,7 @@ defmodule RDF.Turtle.Encoder do
     raise "unknown Turtle document element: #{inspect(element)}"
   end
 
-  defp base_iri(nil, %RDF.Graph{base_iri: base_iri}) when not is_nil(base_iri), do: base_iri
+  defp base_iri(nil, %Graph{base_iri: base_iri}) when not is_nil(base_iri), do: base_iri
   defp base_iri(nil, _), do: RDF.default_base_iri()
   defp base_iri(base_iri, _), do: IRI.coerce_base(base_iri)
 
@@ -91,19 +96,10 @@ defmodule RDF.Turtle.Encoder do
     end
   end
 
-  defp prefixes(nil, %RDF.Graph{prefixes: prefixes}) when not is_nil(prefixes), do: prefixes
+  defp prefixes(nil, %Graph{prefixes: prefixes}) when not is_nil(prefixes), do: prefixes
 
-  defp prefixes(nil, %RDF.Dataset{} = dataset) do
-    prefixes =
-      dataset
-      |> RDF.Dataset.graphs()
-      |> Enum.reduce(RDF.PrefixMap.new(), fn graph, prefixes ->
-        if graph.prefixes do
-          RDF.PrefixMap.merge!(prefixes, graph.prefixes, :ignore)
-        else
-          prefixes
-        end
-      end)
+  defp prefixes(nil, %Dataset{} = dataset) do
+    prefixes = Dataset.prefixes(dataset)
 
     if Enum.empty?(prefixes) do
       RDF.default_prefixes()
@@ -113,7 +109,7 @@ defmodule RDF.Turtle.Encoder do
   end
 
   defp prefixes(nil, _), do: RDF.default_prefixes()
-  defp prefixes(prefixes, _), do: RDF.PrefixMap.new(prefixes)
+  defp prefixes(prefixes, _), do: PrefixMap.new(prefixes)
 
   defp init_prefixes(prefixes) do
     Enum.reduce(prefixes, %{}, fn {prefix, iri}, reverse ->

test/support/rdf_case.ex

@@ -11,7 +11,8 @@ defmodule RDF.Test.Case do
 
   using do
     quote do
-      alias RDF.{Dataset, Graph, Description, IRI, XSD, PropertyMap}
+      alias RDF.{Dataset, Graph, Description, IRI, XSD, PrefixMap, PropertyMap}
+      alias RDF.NS.{RDFS, OWL}
       alias unquote(__MODULE__).{EX, FOAF}
 
       import RDF, only: [iri: 1, literal: 1, bnode: 1]

test/unit/dataset_test.exs

@@ -1757,6 +1757,14 @@ defmodule RDF.DatasetTest do
            )
   end
 
+  test "prefixes/1" do
+    assert Dataset.new()
+           |> Dataset.add(Graph.new(prefixes: [ex: EX, foo: RDFS]))
+           |> Dataset.add(Graph.new(name: EX.Graph, prefixes: [ex: EX, foo: OWL]))
+           |> Dataset.prefixes() ==
+             PrefixMap.new(ex: EX, foo: RDFS)
+  end
+
   describe "Enumerable protocol" do
     test "Enum.count" do
       assert Enum.count(Dataset.new(name: EX.foo())) == 0