class ActiveRecord::DynamicScopeMatch

def self.match(method)
  ds_match = self.new(method)
  ds_match.scope ? ds_match : nil
end

def initialize(method)
  @scope = true
  case method.to_s
  when /^scoped_by_([_a-zA-Z]\w*)$/
    names = $1
  else
    @scope = nil
  end
  @attribute_names = names && names.split('_and_')
end

def scope?
  !@scope.nil?
end