    The following enumerations and types can be used by members of parser
classes generated by bic(). They are actually protected members inherited from
the parser's base class.
    itemization(
    it() bf(Base::ErrorRecovery_):nl()
        This enumeration defines one values:
        verb(
    UNEXPECTED_TOKEN_
        )
       When the parsing process throws tt(UNEXPECTED_TOKEN_) the recovery
        procedure is started (i.e., it is started whenever a syntactic error
        is encountered or tt(ERROR)tt(()) is called).

        The recovery procedure consists of (1) looking for the first state on
        the state-stack having an error-production, followed by (2) handling
        all state transitions that are possible without retrieving a terminal
        token. Then, in the state requiring a terminal token and starting with
        the initial unexpected token (3) all subsequent terminal tokens are
        ignored until a token is retrieved which is a continuation token in
        that state. 

        If the error recovery procedure fails (i.e., if no acceptable token is
        ever encountered) error recovery falls back to the default recovery
        mode: the parsing process terminates.

    it() bf(Base::Return_):nl()
        This enumeration defines two values:
        verb(
    PARSE_ACCEPT = 0,
    PARSE_ABORT = 1
        )
        (which are also used as the tt(parse) function's return values).
     )

When the tt(%polymorphic) directive is used:
    itemization(
    it() bf(Meta_::sizeofTag_):nl()
           tt(sizeofTag_) defines the number of tags that were defined for 
            polymorphic semantic values.
    )

    
