将动态属性添加到 python class 失败

Question

我正在尝试动态地向来自 javalang 的某些 class 添加属性：

In [1]: import javalang
In [2]: tree = javalang.parse.parse("class A { B c = ddd.doSomething(); }")
In [3]: print(tree.types[0].body[0].declarators[0].initializer)
MethodInvocation(arguments=[], member=doSomething, postfix_operators=[], prefix_operators=[], qualifier=ddd, selectors=[], type_arguments=None)

但是当我尝试简单地分配一个新属性时 (qualifier_type)

In [4]: tree.types[0].body[0].declarators[0].initializer.qualifier_type = "DDD"

没有任何反应：

In [5]: print(tree.types[0].body[0].declarators[0].initializer)
MethodInvocation(arguments=[], member=doSomething, postfix_operators=[], prefix_operators=[], qualifier=ddd, selectors=[], type_arguments=None)

Answer 1

显然，我的属性一直存在，只是没有打印出来，因为 __repr__ 实现迭代了 self.attrs。

In [1]: import javalang
In [2]: tree = javalang.parse.parse("class A { B c = ddd.doSomething(); }")
In [3]: tree.types[0].body[0].declarators[0].initializer.qualifier_type = "DDD"
In [4]: print(tree.types[0].body[0].declarators[0].initializer.qualifier_type)
DDD

明确添加我的属性，我现在可以打印我的 class（向右滚动查看）

In [5]: tree.types[0].body[0].declarators[0].initializer.attrs += ("qualifier_type",)
In [6]: print(tree.types[0].body[0].declarators[0].initializer)
MethodInvocation(arguments=[], member=doSomething, postfix_operators=[], prefix_operators=[], qualifier=ddd, qualifier_type=DDD, selectors=[], type_arguments=None)

将动态属性添加到 python class 失败

Adding dynamic attribute to python class fails

python

attributes

dynamic