GIN BOOLEAN CONST DO ELSE ELSIF END EXIT FALSE FOR IF
INTEGER LOOP MOD OF OR PROGRAM RETURN THEN TO TRUE VAR WHILE
</pre>

    An identifier is a freely chosen representation for an object.  It
    is given meaning by a construct of the program. The appearances at
    which an identifier is given a meaning are called <em>defining
    occurrences</em> of that identifier.  All other appearances of the
    identifier are called <em>applied occurrences</em>.<p>

    Denotations have the usual meanings.<p>

    