--- ARGF.to_s
--- ARGF.filename
--- ARGF.path   ruby 1.8 feature

    оݤΥե֤̾ޤɸϤФƤ - ֤
    ޤȤ߹ѿ $FILENAME ƱǤ

    ruby 1.8 feature:
    to_s ϡʸ "ARGF" ֤ޤ

