Question: Using rac_lift with methods that accept primitive types?

[tonyarnold]

Hi Guys, is it possible to use rac_lift (or some variant) to replace a call to subscribeNext?

Concrete example: Can I make something like this more succinct?

[[[RACAbleWithStart(self.tickFrequency) distinctUntilChanged] deliverOn:[RACScheduler mainThreadScheduler]] subscribeNext:^(NSNumber *x) {
    @strongify(self);
    [self setNeedsDisplay:YES];
}];

[alanjrogers]

@tonyarnold You sure can! I think the code below will work.

RACSignal *tickSignal = [[[RACAbleWithStart(self.tickFrequency) 
    distinctUntilChanged]
    mapReplace:@YES]
    deliverOn:RACScheduler.mainThreadScheduler];

[self rac_liftSelector:@selector(setNeedsDisplay:) withObjects:tickSignal];

That will effectively call [self setNeedsDisplay:YES] every time self.tickSignal is changed.

@jspahrsummers will pipe up If I'm wrong 😀

PS. I threw in some dot syntax cause I know how much you ❤️ it.

[tonyarnold]

Wait wait wait, that's more code. sigh Sometimes I understand, sometimes I do not.

I hope you and your dots are happy together! 🚪

(The code works fine, thanks!)

[alanjrogers]

It's not more code, I just spread it over more lines :D

[jspahrsummers]

We prefer the more declarative style (selector lifting), because it makes the intention extremely clear. You're invoking -setNeedsDisplay: over time, but the -subscribeNext: obfuscates that somewhat.

Using rac_liftSelector: also neatly avoids the weakify/strongify dance.