Constants

 

ConstDeclaration ::= Ident ":=" Expression ";" |
		     Ident "=" Expression ";" |
		     Ident ":" Expression ";"
ConstDeclarationList ::= 
      ConstDeclarationList ConstDeclaration |
      ConstDeclaration
ConstDeclarations ::= "CONST" ConstDeclarationList

Constants are named entities which value cannot be changed. They behave like read-only variables. Each constant is denoted by a system-wide unique name (except for local scopes that can redefine the variable's name) and by an expression that is evaluated when the script is started, and which value is retained as long as the script runs.

CONST
  Pi = 3.1415;
  Epsilon = 0.0001;
  PiSquare := Pi * Pi;