'The only identifiers that can contain \'.\' are versions, but version
ids are context-sensitive so we have to check on a case-by-case
basis. Call this if we detect a version id where it shouldn\'t be.'

def check_identifier(self, id=None):

    if (not id):
        id = self.token.value
    if ('.' in id):
        self.last_token_error("{0}:    Identifier    cannot    contain    '.'".format(id))
