Support for the XPath ">" operator.

lib/oga/xpath/evaluator.rb

@@ -770,6 +770,22 @@ module Oga
         return on_call_number(context, left) < on_call_number(context, right)
       end
 
+      ##
+      # Processes the `>` operator.
+      #
+      # This operator converts the left and right expression to a number and
+      # returns `true` if the first number is greater than the second number.
+      #
+      # @param [Oga::XML::Node] ast_node
+      # @param [Oga::XML::NodeSet] context
+      # @return [TrueClass|FalseClass]
+      #
+      def on_gt(ast_node, context)
+        left, right = *ast_node
+
+        return on_call_number(context, left) > on_call_number(context, right)
+      end
+
       ##
       # Delegates function calls to specific handlers.
       #

spec/oga/xpath/evaluator/operators/gt_spec.rb

@@ -0,0 +1,42 @@
+require 'spec_helper'
+
+describe Oga::XPath::Evaluator do
+  context 'greater-than operator' do
+    before do
+      @document  = parse('<root><a>10</a><b>20</b></root>')
+      @evaluator = described_class.new(@document)
+    end
+
+    example 'return true if a number is greater than another number' do
+      @evaluator.evaluate('20 > 10').should == true
+    end
+
+    example 'return false if a number is not greater than another number' do
+      @evaluator.evaluate('10 > 20').should == false
+    end
+
+    example 'return true if a number is greater than a string' do
+      @evaluator.evaluate('20 > "10"').should == true
+    end
+
+    example 'return true if a string is greater than a number' do
+      @evaluator.evaluate('"20" > 10').should == true
+    end
+
+    example 'return true if a string is greater than another string' do
+      @evaluator.evaluate('"20" > "10"').should == true
+    end
+
+    example 'return true if a number is greater than a node set' do
+      @evaluator.evaluate('20 > root/a').should == true
+    end
+
+    example 'return true if a string is greater than a node set' do
+      @evaluator.evaluate('"20" > root/a').should == true
+    end
+
+    example 'return true if a node set is greater than another node set' do
+      @evaluator.evaluate('root/b > root/a').should == true
+    end
+  end
+end