parser.py 文件源码

def parse_for(self):
        """Parse a for loop."""
        lineno = self.stream.expect('name:for').lineno
        target = self.parse_assign_target(extra_end_rules=('name:in',))
        self.stream.expect('name:in')
        iter = self.parse_tuple(with_condexpr=False,
                                extra_end_rules=('name:recursive',))
        test = None
        if self.stream.skip_if('name:if'):
            test = self.parse_expression()
        recursive = self.stream.skip_if('name:recursive')
        body = self.parse_statements(('name:endfor', 'name:else'))
        if next(self.stream).value == 'endfor':
            else_ = []
        else:
            else_ = self.parse_statements(('name:endfor',), drop_needle=True)
        return nodes.For(target, iter, body, else_, test,
                         recursive, lineno=lineno)