Add support for N-Quads-star decoding

src/nquads_parser.yrl

@@ -1,7 +1,7 @@
 %% Grammar for N-Quads as specified in http://www.w3.org/TR/2014/REC-n-quads-20140225/
 
-Nonterminals nquadsDoc nonEmptyNquadsDoc statement subject predicate object graphLabel literal eols.
-Terminals iriref blank_node_label string_literal_quote langtag '^^' '.' eol.
+Nonterminals nquadsDoc nonEmptyNquadsDoc statement subject predicate object graphLabel literal quoted_triple eols.
+Terminals iriref blank_node_label string_literal_quote langtag '^^' '.' '<<' '>>' eol.
 Rootsymbol nquadsDoc.
 
 eols -> eols eol.
@@ -25,10 +25,12 @@ statement -> subject predicate object '.' : { '$1', '$2', '$3' }.
 
 subject    -> iriref            : to_iri('$1').
 subject    -> blank_node_label  : to_bnode('$1').
+subject    -> quoted_triple     : '$1'.
 predicate  -> iriref            : to_iri('$1').
 object     -> iriref            : to_iri('$1').
 object     -> blank_node_label  : to_bnode('$1').
 object     -> literal           : '$1'.
+object     -> quoted_triple     : '$1'.
 graphLabel -> iriref            : to_iri('$1').
 graphLabel -> blank_node_label  : to_bnode('$1').
 
@@ -36,6 +38,7 @@ literal -> string_literal_quote '^^' iriref : to_literal('$1', {datatype, to_iri
 literal -> string_literal_quote langtag     : to_literal('$1', {language, to_langtag('$2')}).
 literal -> string_literal_quote             : to_literal('$1').
 
+quoted_triple -> '<<' subject predicate object '>>' : { '$2', '$3', '$4' }.
 
 Erlang code.
 

test/acceptance/nquads_star_test.exs

@@ -0,0 +1,65 @@
+defmodule RDF.Star.NQuads.TestSuite do
+  @moduledoc """
+  RDF-star N-Quads Test Suite.
+
+  This runs the official RDF-star N-Triples Test Suite and variations of its
+  test files with added graph names against the `RDF.NQuads.Decoder`.
+  """
+
+  use ExUnit.Case, async: false
+
+  import RDF.Sigils
+
+  @ntriples_star_test_suite_path "rdf-star/nt/syntax"
+  @nquads_star_test_suite_path "rdf-star/nq/syntax"
+  @ntriples_star_test_suite Path.join(RDF.TestData.dir(), @ntriples_star_test_suite_path)
+  @nquads_star_test_suite Path.join(RDF.TestData.dir(), @nquads_star_test_suite_path)
+
+  ExUnit.Case.register_attribute(__ENV__, :nt_test)
+  ExUnit.Case.register_attribute(__ENV__, :nq_test)
+
+  @ntriples_star_test_suite
+  |> File.ls!()
+  |> Enum.filter(fn file -> Path.extname(file) == ".nt" end)
+  |> Enum.each(fn file ->
+    @nt_test file: Path.join(@ntriples_star_test_suite, file)
+    if file |> String.contains?("-bad-") do
+      test "Negative syntax test: #{file}", context do
+        assert {:error, _} = RDF.NQuads.read_file(context.registered.nt_test[:file])
+      end
+    else
+      test "Positive syntax test: #{file}", context do
+        assert {:ok, %RDF.Dataset{}} = RDF.NQuads.read_file(context.registered.nt_test[:file])
+      end
+    end
+  end)
+
+  @nquads_star_test_suite
+  |> File.ls!()
+  |> Enum.filter(fn file -> Path.extname(file) == ".nq" end)
+  |> Enum.each(fn file ->
+    @nq_test file: Path.join(@nquads_star_test_suite, file)
+    test "Positive syntax test: #{file}", context do
+      nq_test_file = context.registered.nq_test[:file]
+      assert {:ok, %RDF.Dataset{} = dataset1} = RDF.NQuads.read_file(nq_test_file)
+
+      nt_test_file =
+        nq_test_file
+        |> String.replace(
+          @nquads_star_test_suite_path <> "/nquads-",
+          @ntriples_star_test_suite_path <> "/ntriples-"
+        )
+        |> String.replace(~r/\.nq$/, ".nt")
+
+      assert {:ok, %RDF.Dataset{} = dataset2} = RDF.NQuads.read_file(nt_test_file)
+
+      assert RDF.Dataset.graph_count(dataset1) == 1
+      assert RDF.Dataset.graph_count(dataset2) == 1
+
+      assert %RDF.Graph{} = graph1 = RDF.Dataset.graph(dataset1, ~I<http://example/Graph>)
+      assert %RDF.Graph{} = graph2 = RDF.Dataset.default_graph(dataset2)
+      #
+      assert RDF.Graph.change_name(graph1, nil) == graph2
+    end
+  end)
+end

test/data/rdf-star/nq/syntax/nquads-star-bnode-1.nq

@@ -0,0 +1,2 @@
+_:b0 <http://example/p> <http://example/o> <http://example/Graph> .
+<< _:b0 <http://example/p> <http://example/o> >> <http://example/q> "ABC" <http://example/Graph> .

test/data/rdf-star/nq/syntax/nquads-star-bnode-2.nq

@@ -0,0 +1,2 @@
+<http://example/s> <http://example/p> _:b1 <http://example/Graph> .
+<< <http://example/s> <http://example/p> _:b1 >> <http://example/q> "456"^^<http://www.w3.org/2001/XMLSchema#integer> <http://example/Graph> .

test/data/rdf-star/nq/syntax/nquads-star-nested-1.nq

@@ -0,0 +1,3 @@
+<http://example/s> <http://example/p> <http://example/o> <http://example/Graph> .
+<< <http://example/s> <http://example/p> <http://example/o> >> <http://example/r> <http://example/z> <http://example/Graph> .
+<< << <http://example/s> <http://example/p> <http://example/o> >> <http://example/r> <http://example/z> >> <http://example/q> "1"^^<http://www.w3.org/2001/XMLSchema#integer> <http://example/Graph> .

test/data/rdf-star/nq/syntax/nquads-star-nested-2.nq

@@ -0,0 +1,3 @@
+<http://example/s> <http://example/p> <http://example/o> <http://example/Graph> .
+<http://example/a> <http://example/q> << <http://example/s> <http://example/p> <http://example/o> >> <http://example/Graph> .
+<< <http://example/a> <http://example/q> << <http://example/s> <http://example/p> <http://example/o> >> >> <http://example/r> <http://example/z> <http://example/Graph> .

test/data/rdf-star/nq/syntax/nquads-star-syntax-1.nq

@@ -0,0 +1 @@
+<< <http://example/s> <http://example/p> <http://example/o> >> <http://example/q> <http://example/z> <http://example/Graph> .

test/data/rdf-star/nq/syntax/nquads-star-syntax-2.nq

@@ -0,0 +1 @@
+<http://example/x> <http://example/p> << <http://example/s> <http://example/p> <http://example/o> >> <http://example/Graph> .

test/data/rdf-star/nq/syntax/nquads-star-syntax-3.nq

@@ -0,0 +1 @@
+<< <http://example/s1> <http://example/p1> <http://example/o1> >> <http://example/q> << <http://example/s2> <http://example/p2> <http://example/o2> >> <http://example/Graph> .

test/data/rdf-star/nq/syntax/nquads-star-syntax-4.nq

@@ -0,0 +1 @@
+<<<http://example/s1><http://example/p1><http://example/o1>>><http://example/q><<<http://example/s2><http://example/p2><http://example/o2>>><http://example/Graph>.

test/data/rdf-star/nq/syntax/nquads-star-syntax-5.nq

@@ -0,0 +1 @@
+<<<<<http://example/s1><http://example/p1><http://example/o1>>><http://example/q1><<<http://example/s2><http://example/p2><http://example/o2>>>>><http://example/q2><<<<<http://example/s3><http://example/p3><http://example/o3>>><http://example/q3><<<http://example/s4><http://example/p4><http://example/o4>>>>><http://example/Graph>.