add OrderedHash[] initialization

lib/mongo/util/ordered_hash.rb

@@ -32,9 +32,28 @@ class OrderedHash < Hash
 
   # We only need the body of this class if the RUBY_VERSION is before 1.9
   if RUBY_VERSION < '1.9'
-
     attr_accessor :ordered_keys
 
+    def self.[] *args
+      oh = OrderedHash.new
+      if Hash === args[0]
+        oh.merge! args[0]
+      elsif (args.size % 2) != 0
+        raise ArgumentError, "odd number of elements for Hash"
+      else
+        0.step(args.size - 1, 2) do |key|
+          value = key + 1
+          oh[args[key]] = args[value]
+        end
+      end
+      oh
+    end
+
+    def initialize(*a, &b)
+      super
+      @ordered_keys = []
+    end
+
     def keys
       @ordered_keys || []
     end
@@ -90,7 +109,5 @@ class OrderedHash < Hash
       super
       @ordered_keys = []
     end
-
-  end                           # Ruby before 1.9
-
+  end
 end

tests/test_db_api.rb

@@ -53,6 +53,10 @@ class DBAPITest < Test::Unit::TestCase
 
     oid = @@coll.save(oh)
     assert_equal 'foo', @@coll.find_first(:_id => oid)['b']
+
+    oh = OrderedHash['a' => 1, 'b' => 'foo']
+    oid = @@coll.save(oh)
+    assert_equal 'foo', @@coll.find_first(:_id => oid)['b']
   end
 
   def test_insert_multiple

tests/test_ordered_hash.rb

@@ -12,6 +12,15 @@ class OrderedHashTest < Test::Unit::TestCase
     @ordered_keys = %w(c a z)
   end
 
+  def test_initialize
+    a = OrderedHash.new
+    a['x'] = 1
+    a['y'] = 2
+
+    b = OrderedHash['x' => 1, 'y' => 2]
+    assert_equal a, b
+  end
+
   def test_empty
     assert_equal [], OrderedHash.new.keys
   end