Write VERSION declaration in N-Triples/Quads if version specified, and not canonicalizing.

Author: gkellogg

lib/rdf/ntriples/writer.rb

@@ -193,6 +193,16 @@ def initialize(output = $stdout, validate: true, **options, &block)
       super
     end
 
+    ##
+    # Output VERSION directive, if specified and not canonicalizing
+    # @return [self]
+    # @abstract
+    def write_prologue
+      puts %(VERSION #{version.inspect}) if version && !canonicalize?
+      @logged_errors_at_prolog = log_statistics[:error].to_i
+      super
+    end
+
     ##
     # Outputs an N-Triples comment line.
     #

lib/rdf/writer.rb

@@ -152,6 +152,12 @@ def self.options
           control: :checkbox,
           on: ["--unique-bnodes"],
           description: "Use unique Node identifiers.") {true},
+        RDF::CLI::Option.new(
+          symbol: :version,
+          control: :select,
+          datatype: RDF::Format::VERSIONS, # 1.1, 1.2, or 1.2-basic
+          on: ["--version VERSION"],
+          description: "RDF Version."),
       ]
     end
 
@@ -281,13 +287,22 @@ def to_sym
     #   Use unique {Node} identifiers, defaults to using the identifier which the node was originall initialized with (if any). Implementations should ensure that Nodes are serialized using a unique representation independent of any identifier used when creating the node. See {NTriples::Writer#format_node}
     # @option options [Hash{Symbol => String}] :accept_params
     #   Parameters from ACCEPT header entry for the media-range matching this writer.
+    # @option options [String] :version
+    #   Parse a specific version of RDF ("1.1', "1.2", or "1.2-basic"")
     # @yield  [writer] `self`
     # @yieldparam  [RDF::Writer] writer
     # @yieldreturn [void]
     def initialize(output = $stdout, **options, &block)
       @output, @options = output, options.dup
       @nodes, @node_id, @node_id_map  = {}, 0, {}
 
+      # The rdfstar option implies version 1.2, but can be overridden
+      @options[:version] ||= "1.2" if @options[:rdfstar]
+
+      unless self.version.nil? || RDF::Format::VERSIONS.include?(self.version)
+        log_warn("Expected version to be one of #{RDF::Format::VERSIONS.join(', ')}, was #{self.version}")
+      end
+
       if block_given?
         write_prologue
         case block.arity
@@ -412,6 +427,18 @@ def flush
     end
     alias_method :flush!, :flush
 
+    ##
+    # Returns the RDF version determined by this reader.
+    #
+    # @example
+    #   writer.version  #=> "1.2"
+    #
+    # @return [String]
+    # @since  3.3.4
+    def version
+      @options[:version]
+    end
+
     ##
     # @return [self]
     # @abstract

spec/nquads_spec.rb

@@ -313,6 +313,30 @@
         .to write_each("<http://example/s> <http://example/p> <http://example/o1> .\n",
                        "<http://example/s> <http://example/p> <http://example/o2> .\n")
     end
+
+    it "writes version with :version option" do
+      expect do
+        described_class.new($stdout, version: "1.2") do |w|
+          w.insert(graph)
+        end
+      end.to write(%(VERSION "1.2"))
+    end
+
+    it "does not write version with :version and :canonicalize options" do
+      expect do
+        described_class.new($stdout, version: "1.2", canonicalize: true) do |w|
+          w.insert(graph)
+        end
+      end.not_to write(%(VERSION "1.2"))
+    end
+
+    it "writes version with :rdfstar option" do
+      expect do
+        described_class.new($stdout, rdfstar: true) do |w|
+          w.insert(graph)
+        end
+      end.to write(%(VERSION "1.2"))
+    end
   end
 
   context "Writing a Statements" do

spec/ntriples_spec.rb

@@ -970,14 +970,39 @@
   context "Writing a Graph" do
     let(:graph) {
       g = RDF::Graph.new
-      g << [RDF::URI('s'), RDF::URI('p'), RDF::URI('o1')]
-      g << [RDF::URI('s'), RDF::URI('p'), RDF::URI('o2'), RDF::URI('c')]
+      g << [RDF::URI('http://example/s'), RDF::URI('http://example/p'), RDF::URI('http://example/o1')]
+      g << [RDF::URI('http://example/s'), RDF::URI('http://example/p'), RDF::URI('http://example/o2'), RDF::URI('c')]
       g
     }
     it "#insert" do
       expect do
-        writer.new($stdout, validate: false).insert(graph)
-      end.to write_each("<s> <p> <o1> .\n", "<s> <p> <o2> .\n")
+        writer.new($stdout).insert(graph)
+      end.to write_each("<http://example/s> <http://example/p> <http://example/o1> .\n",
+                        "<http://example/s> <http://example/p> <http://example/o2> .\n")
+    end
+
+    it "writes version with :version option" do
+      expect do
+        writer.new($stdout, version: "1.2") do |w|
+          w.insert(graph)
+        end
+      end.to write(%(VERSION "1.2"))
+    end
+
+    it "does not write version with :version and :canonicalize options" do
+      expect do
+        writer.new($stdout, version: "1.2", canonicalize: true) do |w|
+          w.insert(graph)
+        end
+      end.not_to write(%(VERSION "1.2"))
+    end
+
+    it "writes version with :rdfstar option" do
+      expect do
+        writer.new($stdout, rdfstar: true) do |w|
+          w.insert(graph)
+        end
+      end.to write(%(VERSION "1.2"))
     end
   end