% $Id: FourLetter.oz,v 1.2 2008/01/08 21:35:24 leavens Exp leavens $ declare % Example of the use of the choice expression fun {Keyword} choice "java" [] "modeling" [] "language" [] "verification" [] "environment" [] "tool" [] "system" [] "project" [] "extensible" [] "advanced" end end fun {Acronym N} if N =< 0 then nil else local First={Keyword}.1 Rest={Acronym N-1} in if {Member First Rest} then fail else First|Rest end end end end fun {FourLetter} {Acronym 4} end