isomorphic.rb in rdf-isomorphic-1.0.2

- old
+ new

@@ -7,11 +7,11 @@
   ##
   # Isomorphism for rdf.rb Enumerables
   #
   # RDF::Isomorphic provides the functions isomorphic_with and bijection_to for RDF::Enumerable.
   #
-  # @see http://ruby-rdf.github.com/rdf
+  # @see http://rdf.rubyforge.org
   # @see http://www.hpl.hp.com/techreports/2001/HPL-2001-293.pdf
   module Isomorphic
     autoload :VERSION,        'rdf/isomorphic/version'
 
     # Returns `true` if this RDF::Enumerable is isomorphic with another.
@@ -157,18 +157,14 @@
       bijection
     end
 
     # Blank nodes appearing in given list of statements
     # @private
-    # @return [RDF::Node]
+    # @param [Array<RDF::Statement>] blank_stmt_list
+    # @return [Array<RDF::Node>]
     def self.blank_nodes_in(blank_stmt_list)
-      nodes = []
-      blank_stmt_list.each do | statement |
-        nodes << statement.object if statement.object.node?
-        nodes << statement.subject if statement.subject.node?
-      end
-      nodes.uniq
+      blank_stmt_list.map {|statement | statement.to_quad.compact.select(&:node?)}.flatten.uniq
     end
 
     # Given a set of statements, create a mapping of node => SHA1 for a given
     # set of blank nodes.  grounded_hashes is a mapping of node => SHA1 pairs
     # that we will take as a given, and use those to make more specific
@@ -228,18 +224,22 @@
     # member in the given hash.
     #
     # Returns a tuple consisting of grounded being true or false and the String
     # for the hash
     # @private
+    # @param [RDF::Node] node
+    # @param [Array<RDF::Statement>] statements
+    # @param [Hash] hashes
+    # @param [Boolean] canonicalize
     # @return [Boolean, String]
     def self.node_hash_for(node, statements, hashes, canonicalize)
       statement_signatures = []
       grounded = true
       statements.each do | statement |
-        if (statement.object == node) || (statement.subject == node)
+        if statement.to_quad.include?(node)
           statement_signatures << hash_string_for(statement, hashes, node, canonicalize)
-          [statement.subject, statement.object].each do | resource |
+          statement.to_quad.compact.each do | resource |
             grounded = false unless grounded?(resource, hashes) || resource == node
           end
         end
       end
       # Note that we sort the signatures--without a canonical ordering, 
@@ -250,15 +250,11 @@
     # Provide a string signature for the given statement, collecting
     # string signatures for grounded node elements.
     # return [String]
     # @private
     def self.hash_string_for(statement, hashes, node, canonicalize)
-      string = ""
-      string << string_for_node(statement.subject, hashes, node, canonicalize)
-      string << statement.predicate.to_s
-      string << string_for_node(statement.object, hashes, node, canonicalize)
-      string 
+      statement.to_quad.map {|r| string_for_node(r, hashes, node, canonicalize)}.join("")
     end
 
     # Returns true if a given node is grounded
     # A node is groundd if it is not a blank node or it is included
     # in the given mapping of grounded nodes.
@@ -273,10 +269,12 @@
     # nodes will return their hashed form.
     # @return [String]
     # @private
     def self.string_for_node(node, hashes,target, canonicalize)
       case
+        when node.nil?
+          ""
         when node == target
           "itself"
         when node.node? && hashes.member?(node)
           hashes[node]
         when node.node?
@@ -294,9 +292,7 @@
 
   # Extend RDF::Enumerables with these functions.
   module Enumerable 
     include RDF::Isomorphic
   end
-
-  autoload :VERSION,  'rdf/isomorphic/version'
 end
 