def include(self):
        """
        If the next line is an include statement, inserts the contents
        of the included file into the pending buffer.
        """
        if len(self.pending) == 0 or not self.pending[0].startswith('include '):
            return
        name = self.pending.pop(0)[8:].strip()[1:-1]
        for b in [os.path.dirname(self.name)] + self.inc_dirs:
            pname = os.path.abspath(os.path.expanduser(os.path.join(b, name)))
            if os.path.isfile(pname):
                name = pname
                break
        else:
            raise Exception('Can not find include file "{}".'.format(name))
        self.pending = list(FortranReader(name, self.docmark, self.predocmark, 
                                          self.docmark_alt, self.predocmark_alt,
                                          self.fixed, self.length_limit,
                                          inc_dirs=self.inc_dirs)) + self.pending
If the next line is an include statement, inserts the contents
        of the included file into the pending buffer.