def p_generate_for(self, p):
        'generate_for : FOR LPAREN forpre forcond forpost RPAREN generate_forcontent'
        p[0] = ForStatement(p[3], p[4], p[5], p[7], lineno=p.lineno(1))
        p.set_lineno(0, p.lineno(1))
generate_for : FOR LPAREN forpre forcond forpost RPAREN generate_forcontent