generic -- GENERIC_SORT ( ELEMENT , INDEX , VECTOR , ">" )
  type ELEMENT is private ; -- simple objects, records or arrays
  type INDEX is ( <> ) ; -- any discrete type
  type VECTOR is array ( INDEX range <> ) of ELEMENT ; -- structure form

--              a comparison function must be provided if ELEMENT
--              is not a type or subtype for which ">" is visible.
--              ONLY the one comparison function is needed.
--              return true if the first parameter is larger than the second
  with function ">" ( SMALL , LARGE : ELEMENT ) return BOOLEAN is <> ;
package GENERIC_SORT is
  procedure SORT ( ARR1 : in out VECTOR ) ;
end GENERIC_SORT ;

-- This is a demonstration of GENERIC_SORT with arrays of records

  subtype MY_STRING is STRING ( 1 .. 3 ) ;
  type MY_ENUM is ( FIRST , SECOND , THIRD , FOURTH ) ;
  type MY_RECORD is -- a vector of this type of record will be sorted
    record
      I : INTEGER ;
      ENUM_PART : MY_ENUM ;
      X : FLOAT ;
      STRING_PART : MY_STRING ;
    end record ;
--      Example , sorting an array of records indexed by an enumeration type
  type MY_ENUM_ARRAY is array ( MY_ENUM range <> ) of MY_RECORD ;

  ENUM_RECORD_DATA : MY_ENUM_ARRAY ( MY_ENUM ) := ( 
     ( 1 , THIRD  , 3.0 , "BBB" ) ,
     ( 2 , FOURTH , 1.0 , "AAA" ) ,
     ( 3 , SECOND , 2.0 , "BBB" ) ,
     ( 4 , THIRD  , 4.0 , "CCC" ) ) ;
--             When sorting records there is no predefined comparison operator
--             Generally some part of the record is the key by which the
--             records are sorted. This example shows a primary key that is
--             ENUM_PART and the use of a secondary key STRING_PART when
--             the primary keys of the two records are equal.
--             Any code may be used in the function. The purpose of the
--             function is to return TRUE if LEFT > RIGHT .
--      Example  comparison function for ">"
  function MY_ENUM_COMPARE ( LEFT , RIGHT :  MY_RECORD ) return BOOLEAN  is
  begin
    return ( LEFT.ENUM_PART > RIGHT.ENUM_PART ) or
       ( LEFT.ENUM_PART = RIGHT.ENUM_PART and
         LEFT.STRING_PART > RIGHT.STRING_PART ) ;
  end MY_ENUM_COMPARE ;

--       Example  instantiation of GENERIC_SORT 
  package ENUM_RECORD_SORT is new GENERIC_SORT ( MY_RECORD , MY_ENUM ,
      MY_ENUM_ARRAY , MY_ENUM_COMPARE ) ;

--      Example , perform the sort and print the results
  ENUM_RECORD_SORT.SORT ( ENUM_RECORD_DATA ) ;