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  CONST <identifier> [ : <type> ] = <constant expression>;
                                  .
                                  .
        <identifier> [ : <type> ] = <constant expression>;
 
  Description
 
    CONST starts a program section that defines constants and typed
    constants. Constants are named values that cannot be modified. Typed
    constants, sometimes called variable constants, are initialized to a
    value and can be used as variables.
 
    The value assigned to a constant identifier can be a constant value
    or a constant expression. A constant expression is evaluated by the
    compiler. The expression may contain other constants, but must not
    contain typed constants or variables. It may not use the address
    operator (@), and may use only the following functions:
 
      Abs    ║  Last    ║  Ord    ║  SizeOf
      Chr    ║  Length  ║  Pred   ║  Succ
      First  ║  Lo      ║  Ptr    ║  Swap
      Hi     ║  Odd     ║  Round  ║  Trunc
 
    A typed constant may be used instead of a variable initialized in
    the program block. A typed constant declared in a procedure or
    function is initialized once at the start of the program, and its
    current value is preserved between calls to the procedure or
    function. The syntax for declaring a simple typed constant of a
    type is illustrated at the top of the screen. Other types of typed
    constants are:
 
    CONST
        string_example : STRING[11] = 'String text';
        array_example  : ARRAY[0..2] OF Char = ( 'A', 'B', 'C' );
        packed_example : ARRAY[0..2] OF Char =  'ABC' ;
        nested_example : ARRAY[0..2, 0..2] OF Byte
                                  = ((1,0,0),(0,1,0),(0,0,1));
        record_example : DateTime = ( Year : 2001; Month : 1; Day : 1;
                                      Hour : 0;    Min   : 0; Sec : 1 );
        set_example    : SET OF 'A'..'Z' = [ 'A', 'E', 'I', 'O', 'U' ];
 
    All elements of arrays and all fields of records must be given a
    value. Pointer typed constants can be initialized only to NIL.
 
  See also:  LABEL, TYPE, VAR