visitor.py 文件源码

def generic_visit(self, node, *args, **kwargs):
        for field, old_value in node.iter_fields():
            if isinstance(old_value, list):
                new_values = []
                for value in old_value:
                    if isinstance(value, Node):
                        value = self.visit(value, *args, **kwargs)
                        if value is None:
                            continue
                        elif not isinstance(value, Node):
                            new_values.extend(value)
                            continue
                    new_values.append(value)
                old_value[:] = new_values
            elif isinstance(old_value, Node):
                new_node = self.visit(old_value, *args, **kwargs)
                if new_node is None:
                    delattr(node, field)
                else:
                    setattr(node, field, new_node)
        return node