A set is a collection of data items of  the  same  ordinal  type
  (called  the  base type).  The SET type definition specifies the
  values that can be elements of a variable of that type.

  Syntax:

     [[PACKED]] SET OF [[attribute-list]] base-type

  The 'attribute-list' is one or more  optional  identifiers  that
  provide additional information about the base type.

  The  'base-type'  is  the  ordinal  type  identifier   or   type
  definition,  or  discriminated  schema  type, from which the set
  elements  are  selected.   Note  that  real  numbers  cannot  be
  elements of a set type.

  Example:  SET OF CHAR

  Some possible set constructors for this set type are:
     ['A, 'E', 'I', 'O', 'U']
     ['B'..'D', 'F'..'H', 'J'..'N', 'P'..'T', 'V'..'Z']