A discriminated schema is a schema type that has  been  provided
  actual discriminants.  Discriminated schema can appear in either
  the TYPE or the VAR sections.  For example:

  TYPE
     Array_Template( Upper_Bound : INTEGER )
  VAR
     Array_Type1 : Array_Template( 10 );  {ARRAY [1..10] OF INTEGER;}
     Array_Type2 : Array_Template( x );   {Upper boundary determined
                                           at run-time by variable or
                                           function call}

  In this example, the actual discriminants 10 and x complete  the
  boundaries  for  Array_Template, forming two complete data types
  within  the  same  schema  type  family.   The  type  specifiers
  Array_Template(  10  )  and  Array_Template( x ) are examples of
  discriminated schema.