module Jeweler::Specification

def self.filelist_attribute(name)
  code = %{
    def #{name}
      if @#{name} && @#{name}.class != FileList
        @#{name} = FileList[@#{name}]
      end
      @#{name} ||= FileList[]
    end
    def #{name}=(value)
      @#{name} = FileList[value]
    end
  }
  module_eval code, __FILE__, __LINE__ - 9
end