production must identify the defining
      occurrence immediately after the "PROGRAM" keyword.

    <h3>Declarations</h3>

<pre>
ParameterDecl : Identifier ":" "INTEGER".
Declarations  : ("CONST" (ConstantDecl ";")+)?
                ("VAR" (VariableDecl ";")+)?.
ConstantDecl  : Identifier "=" Integer.
VariableDecl  : Identifier ":" TypeSpec.
TypeSpec      : "INTEGER"
              | "BOOLEAN"
              | "ARRAY" Integer "OF" "INTEGER".
</pre>

    <h4>Values, Types, Objects, and Variables</h4>

    <e