ordered_hash_merge_with_block.rb

module ActiveSupport
  class OrderedHash

    def merge!(other_hash)
      other_hash.each do |k, v|
        self[k] = block_given? ? yield(k, self[k], v) : v
      end
      self
    end

    def merge(other_hash, &block)
      dup.merge!(other_hash, &block)
    end

  end
end

oredered_hash_deep_merge.rb

module ActiveSupport #:nodoc:
  module CoreExtensions #:nodoc:
    module Hash #:nodoc:
      # Allows for deep merging
      module DeepMerge
        # Returns a new hash with +self+ and +other_hash+ merged recursively.
        def deep_merge(other_hash)
          self.merge(other_hash) do |key, oldval, newval|
            oldval = oldval.to_hash if oldval.respond_to?(:to_hash)
            newval = newval.to_hash if newval.respond_to?(:to_hash)
            (oldval.class.to_s == 'Hash' || oldval.class.to_s == 'ActiveSupport::OrderedHash') && (newval.class.to_s == 'Hash' || newval.class.to_s == 'ActiveSupport::OrderedHash') ? oldval.deep_merge(newval) : newval
          end
        end
      end
    end
  end
end

test.rb

def test_deep_merge
    @ordered_hash['deep'] = ActiveSupport::OrderedHash.new
    @ordered_hash['deep']['number'] = 1
    @ordered_hash['deep']['place'] = 'here'
    
    other_hash = ActiveSupport::OrderedHash.new
    other_hash['deep'] = ActiveSupport::OrderedHash.new
    other_hash['deep']['number'] = 5
    
    merged = @ordered_hash.deep_merge(other_hash)
    
    #should merge the nested hash
    assert 5, merged['deep']['number']
    assert 'here', merged['deep']['place']
  end