ann 
   "forceUsed"
   "warnUnused false"
   "sequenceNonUnit ignore"
   "nonexhaustiveMatch ignore"
in
   local
      $(SML_LIB)/basis/basis.mlb
      trail.sig
      trail.sml
      notrail.sml
   in
      signature TRAIL
      structure Trail
      structure NoTrail
   end
end