Objective c 将属性直接绑定到信号是否等同于订阅该信号，然后设置属性？

不要在我的视图控制器中写入此内容：

@weakify(self);
[[self.view.emailAddressField.rac_textSignal distinctUntilChanged] subscribeNext:^(NSString *emailAddress) {
    @strongify(self);
    self.viewModel.emailAddress = emailAddress;
}];

使用以下内容的后果和影响是什么

RAC(self.viewModel, emailAddress) = [self.view.emailAddressField.rac_textSignal distinctUntilChanged];

---

它们是等效的，假设调用时已设置了

self.viewModel

。

它们是等效的，假设调用时已设置了

self.viewModel

。

请阅读源代码

RAC(target, keyPath, nilValue) = signal;

有点像：

[signal setkeyPath:keyPath onObject:target nilValue:niValue];

而

setKeyPath:onObject:nilValue:

的实现如下所示：

RACDisposable *subscriptionDisposable = [self subscribeNext:^(id x) {
    NSObject *object = (__bridge id)objectPtr;
    [object setValue:x ?: nilValue forKeyPath:keyPath];
} error:^(NSError *error) {
    ...
} completed:^{
    ...
}];

---

只需阅读源代码

RAC(target, keyPath, nilValue) = signal;

有点像：

[signal setkeyPath:keyPath onObject:target nilValue:niValue];

而

setKeyPath:onObject:nilValue:

的实现如下所示：

RACDisposable *subscriptionDisposable = [self subscribeNext:^(id x) {
    NSObject *object = (__bridge id)objectPtr;
    [object setValue:x ?: nilValue forKeyPath:keyPath];
} error:^(NSError *error) {
    ...
} completed:^{
    ...
}];