reader.rb in rdf-json-0.3.0.pre

- old
+ new

@@ -1,9 +1,12 @@
 module RDF::JSON
   ##
   # RDF/JSON parser.
   #
+  # @example Loading RDF/JSON parsing support
+  #   require 'rdf/json'
+  #
   # @example Obtaining an RDF/JSON reader class
   #   RDF::Reader.for(:json)         #=> RDF::JSON::Reader
   #   RDF::Reader.for("etc/doap.json")
   #   RDF::Reader.for(:file_name      => "etc/doap.json")
   #   RDF::Reader.for(:file_extension => "json")
@@ -27,10 +30,12 @@
   # @see http://n2.talis.com/wiki/RDF_JSON_Specification
   class Reader < RDF::Reader
     format RDF::JSON::Format
 
     ##
+    # The graph constructed when parsing.
+    #
     # @return [RDF::Graph]
     attr_reader :graph
 
     ##
     # Initializes the RDF/JSON reader instance.
@@ -41,11 +46,11 @@
     # @yieldparam [Reader] reader
     def initialize(input = $stdin, options = {}, &block)
       super do
         @graph = RDF::Graph.new
 
-        JSON.parse(@input.read).each do |subject, predicates|
+        ::JSON.parse(@input.read).each do |subject, predicates|
           subject = parse_subject(subject)
           predicates.each do |predicate, objects|
             predicate = parse_predicate(predicate)
             objects.each do |object|
               object = parse_object(object)
@@ -63,67 +68,103 @@
     #
     # @param  [String] subject
     # @return [RDF::Resource]
     def parse_subject(subject)
       case subject
-        when /^_:/ then RDF::Node.new(subject[2..-1])
-        else RDF::URI.new(subject)
+        when /^_:/ then parse_node(subject)
+        else parse_uri(subject)
       end
     end
 
     ##
     # Parses an RDF/JSON predicate string into a URI reference.
     #
     # @param  [String] predicate
     # @return [RDF::URI]
     def parse_predicate(predicate)
-      # TODO: optional support for CURIE predicates (issue #1 on GitHub).
-      RDF::URI.intern(predicate)
+      # TODO: optional support for CURIE predicates? (issue #1 on GitHub).
+      parse_uri(predicate, :intern => true)
     end
 
     ##
     # Parses an RDF/JSON object string into an RDF value.
     #
     # @param  [Hash{String => Object}] object
     # @return [RDF::Value]
     def parse_object(object)
-      raise RDF::ReaderError.new, "missing 'type' key in #{object.inspect}"  unless object.has_key?('type')
-      raise RDF::ReaderError.new, "missing 'value' key in #{object.inspect}" unless object.has_key?('value')
+      raise RDF::ReaderError, "missing 'type' key in #{object.inspect}"  unless object.has_key?('type')
+      raise RDF::ReaderError, "missing 'value' key in #{object.inspect}" unless object.has_key?('value')
 
       case type = object['type']
         when 'bnode'
-          RDF::Node.new(object['value'][2..-1])
+          parse_node(object['value'])
         when 'uri'
-          RDF::URI.new(object['value'])
+          parse_uri(object['value'])
         when 'literal'
-          RDF::Literal.new(object['value'], {
+          literal = RDF::Literal.new(object['value'], {
             :language => object['lang'],
             :datatype => object['datatype'],
           })
+          literal.validate!     if validate?
+          literal.canonicalize! if canonicalize?
+          literal
         else
           raise RDF::ReaderError, "expected 'type' to be 'bnode', 'uri', or 'literal', but got #{type.inspect}"
       end
     end
 
     ##
+    # Parses an RDF/JSON blank node string into an `RDF::Node` instance.
+    #
+    # @param  [String] string
+    # @return [RDF::Node]
+    def parse_node(string)
+      RDF::Node.new(string[2..-1]) # strips off the initial '_:'
+    end
+    alias_method :parse_bnode, :parse_node
+
+    ##
+    # Parses an RDF/JSON URI string into an `RDF::URI` instance.
+    #
+    # @param  [String] string
+    # @param  [Hash{Symbol => Object}] options
+    # @option options [Boolean] :intern (false)
+    # @return [RDF::URI]
+    def parse_uri(string, options = {})
+      uri = RDF::URI.send(intern = intern? && options[:intern] ? :intern : :new, string)
+      uri.validate!     if validate?
+      uri.canonicalize! if canonicalize? && !intern
+      uri
+    end
+
+    ##
     # @private
     # @see   RDF::Reader#each_graph
     # @since 0.2.0
     def each_graph(&block)
-      block_given? ? @block.call(@graph) : enum_for(:each_graph).extend(RDF::Countable)
+      if block_given?
+        block.call(@graph)
+      end
+      enum_graph
     end
 
     ##
     # @private
     # @see   RDF::Reader#each_statement
     def each_statement(&block)
-      block_given? ? @graph.each_statement(&block) : enum_for(:each_statement).extend(RDF::Countable)
+      if block_given?
+        @graph.each_statement(&block)
+      end
+      enum_statement
     end
 
     ##
     # @private
-    # @see   RDF::Reader#each_statement
+    # @see   RDF::Reader#each_triple
     def each_triple(&block)
-      block_given? ? @graph.each_triple(&block) : enum_for(:each_triple).extend(RDF::Countable)
+      if block_given?
+        @graph.each_triple(&block)
+      end
+      enum_triple
     end
-  end # class Reader
-end # module RDF::JSON
+  end # Reader
+end # RDF::JSON