Partially support parenthesized xpath (#317)

Fix #25, and also reverts #122.

Adds a new path_stack operator `:group`

Author: tompng

lib/rexml/parsers/xpathparser.rb

@@ -654,7 +654,7 @@ def PrimaryExpr path, parsed
           contents = contents[1..-2]
           n = []
           OrExpr( contents, n )
-          parsed.concat(n)
+          parsed.push(:group, n)
         end
         path
       end

lib/rexml/xpath_parser.rb

@@ -439,7 +439,18 @@ def expr( path_stack, nodeset, context=nil )
           end
           Functions.context = target_context
           return Functions.send(func_name, *args)
-
+        when :group
+          sub_expression = path_stack.shift
+          result = expr(sub_expression, nodeset, context)
+          if result.is_a?(Array)
+            # If result is a nodeset, apply following predicates
+            path_stack.unshift(:node)
+            nodeset = step(path_stack) do
+              [result]
+            end
+          else
+            return result
+          end
         else
           raise "[BUG] Unexpected path: <#{op.inspect}>: <#{path_stack.inspect}>"
         end
@@ -594,7 +605,6 @@ def filter_nodeset(nodeset)
 
     def evaluate_predicate(expression, nodesets)
       enter(:predicate, expression, nodesets) if @debug
-      new_nodeset_count = 0
       new_nodesets = nodesets.collect do |nodeset|
         new_nodeset = []
         subcontext = { :size => nodeset.size }
@@ -611,20 +621,17 @@ def evaluate_predicate(expression, nodesets)
           result = result[0] if result.kind_of? Array and result.length == 1
           if result.kind_of? Numeric
             if result == node.position
-              new_nodeset_count += 1
-              new_nodeset << XPathNode.new(node, position: new_nodeset_count)
+              new_nodeset << XPathNode.new(node, position: new_nodeset.size + 1)
             end
           elsif result.instance_of? Array
             if result.size > 0 and result.inject(false) {|k,s| s or k}
               if result.size > 0
-                new_nodeset_count += 1
-                new_nodeset << XPathNode.new(node, position: new_nodeset_count)
+                new_nodeset << XPathNode.new(node, position: new_nodeset.size + 1)
               end
             end
           else
             if result
-              new_nodeset_count += 1
-              new_nodeset << XPathNode.new(node, position: new_nodeset_count)
+              new_nodeset << XPathNode.new(node, position: new_nodeset.size + 1)
             end
           end
         end

test/xpath/test_base.rb

@@ -575,18 +575,45 @@ def test_nested_predicates
       matches = XPath.match(doc, '(/div/div/test[3])').map(&:text)
       assert_equal [], matches
 
+      matches = XPath.match(doc, '/div/div/test[1][1]').map(&:text)
+      assert_equal ["ab", "ef", "hi"], matches
       matches = XPath.match(doc, '(/div/div/test[1])[1]').map(&:text)
       assert_equal ["ab"], matches
+      matches = XPath.match(doc, '/div/div/test[1][2]').map(&:text)
+      assert_equal [], matches
       matches = XPath.match(doc, '(/div/div/test[1])[2]').map(&:text)
       assert_equal ["ef"], matches
       matches = XPath.match(doc, '(/div/div/test[1])[3]').map(&:text)
       assert_equal ["hi"], matches
+      matches = XPath.match(doc, '/div/div/test[2][1]').map(&:text)
+      assert_equal ["cd", "gh"], matches
       matches = XPath.match(doc, '(/div/div/test[2])[1]').map(&:text)
       assert_equal ["cd"], matches
+      matches = XPath.match(doc, '/div/div/test[2][2]').map(&:text)
+      assert_equal [], matches
       matches = XPath.match(doc, '(/div/div/test[2])[2]').map(&:text)
       assert_equal ["gh"], matches
       matches = XPath.match(doc, '(/div/div/test[2])[3]').map(&:text)
       assert_equal [], matches
+      matches = XPath.match(doc, '//div[1]/test|//div[2]/test[2]').map(&:text)
+      assert_equal ["ab", "cd", "gh"], matches
+      matches = XPath.match(doc, '(//div[1]/test|//div[2]/test)[2]').map(&:text)
+      assert_equal ["cd"], matches
+
+      xpath = '/div/div/test/preceding::*'
+      without_parentheses = XPath.match(doc, xpath).map(&:text)
+      with_parentheses = XPath.match(doc, "(#{xpath})").map(&:text)
+      assert_equal without_parentheses, with_parentheses
+
+      xpath = '/div/div/test/preceding-sibling::*'
+      without_parentheses = XPath.match(doc, xpath).map(&:text)
+      with_parentheses = XPath.match(doc, "(#{xpath})").map(&:text)
+      assert_equal without_parentheses, with_parentheses
+
+      xpath = '/div/div/test/ancestor::*'
+      without_parentheses = XPath.match(doc, xpath).map(&:text)
+      with_parentheses = XPath.match(doc, "(#{xpath})").map(&:text)
+      assert_equal without_parentheses, with_parentheses
     end
 
     # Contributed by Mike Stok