Constants

Constants are identifiers that represent literals or constant expressions 
that can not be changed after they are defined.

For example, Const PI = 3.1415926535897932 will always mean that the 
identifier PI refers to the number 3.1415926535897932.  The identifier PI 
can be used instead of repeating the full number in source.

Global constants once defined, are available globally and the identifier 
can be used to refer to the constant anywhere in the source program. 

After an identifier is defined with the Const statement, the symbol cannot 
be altered. If code tries to alter a constant, an error message will result 
upon code compilation.

Built-in constants include the Boolean data type values True and False.

A constant definition differs from a variable definition.  Variables hold 
values that can be changed.

Example
   Declare Sub PrintConstants ()

   Const FirstNumber = 1
   Const SecondNumber = 2
   Const FirstString = "First string."
   Const FirstBoolean = False
   Const SecondBoolean = True

   Print FirstNumber, SecondNumber 'This will print 1      2
   Print FirstString 'This will print First string.
   Print FirstBoolean, SecondBoolean 'This will print false      true
   Print

   PrintConstants ()

   Sub PrintConstants ()
      Print FirstNumber, SecondNumber 'This will also print 1        2
      Print FirstString 'This will also print First string.
      Print FirstBoolean, SecondBoolean 'This will also print false      true
   End Sub

See also
   * Constant Expressions
   * Literals
   * Const
   * Enum

