lib/sparql/algebra/operator/union.rb in sparql-1.0.1 vs lib/sparql/algebra/operator/union.rb in sparql-1.0.2

@@ -27,23 +27,22 @@
       # @return [RDF::Query::Solutions]
       #   the resulting solution sequence
       # @see    http://www.w3.org/TR/rdf-sparql-query/#sparqlAlgebra
       def execute(queryable, options = {})
         debug(options) {"Union"}
-        solutions1 = operand(0).execute(queryable, options.merge(:depth => options[:depth].to_i + 1))
-        debug(options) {"=>(left) #{solutions1.inspect}"}
-        solutions2 = operand(1).execute(queryable, options.merge(:depth => options[:depth].to_i + 1))
-        debug(options) {"=>(right) #{solutions2.inspect}"}
-        @solutions = RDF::Query::Solutions.new(solutions1 + solutions2)
+        @solutions = RDF::Query::Solutions.new(operands.inject([]) do |memo, op|
+          solns = op.execute(queryable, options.merge(:depth => options[:depth].to_i + 1))
+          debug(options) {"=> (op) #{solns.inspect}"}
+          memo + solns
+        end)
         debug(options) {"=> #{@solutions.inspect}"}
         @solutions
       end
       
       ##
       # Returns an optimized version of this query.
       #
-      # If optimize operands, and if the first two operands are both Queries, replace
-      # with the unique sum of the query elements
+      # Optimize operands and remove any which are empty.
       #
       # @return [Union, RDF::Query] `self`
       def optimize
         ops = operands.map {|o| o.optimize }.select {|o| o.respond_to?(:empty?) && !o.empty?}
         @operands = ops