Updates for Ruby 2.6 compatibility.

lib/rdf/rdfxml/writer.rb

@@ -180,6 +180,14 @@ def write_epilogue
 
   protected
 
+    # Reset parser to run again
+    def reset
+      @options[:log_depth] = 0
+      @references = {}
+      @serialized = {}
+      @subjects = {}
+    end
+
     # Render document using `haml_template[:doc]`. Yields each subject to be rendered separately.
     #
     # @param [Array<RDF::Resource>] subjects
@@ -209,8 +217,8 @@ def render_document(subjects, lang: nil, base: nil, **options, &block)
       builder.instruct! :xml, :version=>"1.0", :encoding=>"UTF-8"
       builder.instruct! :'xml-stylesheet', type: 'text/xsl', href: options[:stylesheet] if options[:stylesheet]
       attrs = prefix_attrs
-      attrs["xml:lang"] = lang if lang
-      attrs["xml:base"] = base if base
+      attrs[:"xml:lang"] = lang if lang
+      attrs[:"xml:base"] = base if base
 
       builder.rdf(:RDF, **attrs) do |b|
         subjects.each do |subject|
@@ -263,18 +271,18 @@ def render_subject(subject, builder, **options, &block)
       types.unshift(first_type) if first_type && !type_qname
       type_qname ||= "rdf:Description"
 
-      attr_props = attr_props.merge("rdf:nodeID" => subject.id) if subject.node? && ref_count(subject) >= 1
-      attr_props = attr_props.merge("rdf:about" => subject.relativize(base_uri)) if subject.uri?
+      attr_props = attr_props.merge("rdf:nodeID": subject.id) if subject.node? && ref_count(subject) >= 1
+      attr_props = attr_props.merge("rdf:about": subject.relativize(base_uri)) if subject.uri?
 
       log_debug {"render_subject(#{subject.inspect})"}
       subject_done(subject)
 
       builder.tag!(type_qname, **attr_props) do |b|
         types.each do |type|
           if type.node?
-            b.tag!("rdf:type",  "rdf:nodeID" => type.id)
+            b.tag!("rdf:type",  "rdf:nodeID": type.id)
           else
-            b.tag!("rdf:type",  "rdf:resource" => type.to_s)
+            b.tag!("rdf:type",  "rdf:resource": type.to_s)
           end
         end
 
@@ -336,11 +344,11 @@ def render_property(property, objects, builder, **options)
             render_subject(object, b, **options)
           end
         elsif object.literal? && object.datatype == RDF.XMLLiteral
-          builder.tag!(property, object.value, "rdf:parseType" => "Literal")
+          builder.tag!(property, object.value, "rdf:parseType": "Literal")
         elsif object.literal?
           attrs = {}
-          attrs["xml:lang"] = object.language if object.language?
-          attrs["rdf:datatype"] = object.datatype if object.datatype?
+          attrs[:"xml:lang"] = object.language if object.language?
+          attrs[:"rdf:datatype"] = object.datatype if object.datatype?
           builder.tag!(property, object.value.to_s, **attrs)
         elsif object.node?
            builder.tag!(property, "rdf:nodeID": object.id)
@@ -368,18 +376,18 @@ def render_property(property, objects, builder, **options)
     # @return String
     #   The rendered collection is returned as a string
     def render_collection(property, list, builder, **options, &block)
-      builder.tag!(property, "rdf:parseType" => "Collection") do |b|
+      builder.tag!(property, "rdf:parseType": "Collection") do |b|
         list.each do |object|
           if log_depth <= @max_depth && !is_done?(object)
             render_subject(object, b)
           elsif object.node?
             if ref_count(object) > 1
-              b.tag!("rdf:Description", "rdf:nodeID" => object.id)
+              b.tag!("rdf:Description", "rdf:nodeID": object.id)
             else
               b.tag!("rdf:Description")
             end
           else
-            b.tag!("rdf:Description", "rdf:about" => object.relativize(base_uri))
+            b.tag!("rdf:Description", "rdf:about": object.relativize(base_uri))
           end
         end
       end
@@ -389,7 +397,7 @@ def render_collection(property, list, builder, **options, &block)
     # @return [Hash{String => String}]
     def prefix_attrs
       prefixes.inject({}) do |memo, (k, v)|
-        memo[k ? "xmlns:#{k}" : "xmlns"] = v.to_s
+        memo[(k ? "xmlns:#{k}" : "xmlns").to_sym] = v.to_s
         memo
       end
     end
@@ -439,14 +447,6 @@ def preprocess_statement(statement)
 
   private
 
-    # Reset parser to run again
-    def reset
-      @options[:log_depth] = 0
-      @references = {}
-      @serialized = {}
-      @subjects = {}
-    end
-
     # Order subjects for output. Override this to output subjects in another order.
     #
     # Uses #top_classes and #base_uri.
@@ -514,7 +514,7 @@ def prop_partition(properties)
             (object.plain? || @attributes == :typed) &&
             get_lang(object).nil?
 
-            attr_props[prop] = values.first.to_s
+            attr_props[prop.to_sym] = values.first.to_s
           else
             embed_props[prop] = values
           end