class Diff::LCS::ContextChange

def initialize(*args)
  @action, @old_position, @old_element, @new_position, @new_element = *args
  unless Diff::LCS::Change.valid_action?(@action)
    raise "Invalid Change Action '#{@action}'"
  end
  unless @old_position.nil? or @old_position.kind_of? Fixnum
    raise "Invalid (Old) Position Type"
  end
  unless @new_position.nil? or @new_position.kind_of? Fixnum
    raise "Invalid (New) Position Type"
  end
end