Reactive Cocoa example with subscripting hack

gistfile1.m

Basically I can turn this:

[[[[loginResult 
    where:^(id x) {
        return [x hasError];
    }] 
    select:^(id x) {
        return [x error];
    }] 
    injectObjectWeakly:self]
    subscribeNext:^(RACTuple *t) {
        GHDLoginViewController *self = t.last;
        self.loginFailedHidden = NO;
        NSLog(@"error logging in: %@", t.first);
    }];


Into this:

[loginResult
    .where[(id)^(id x) {
        return [x hasError];
    }] 
    .select[(id)^(id x) {
        return [x error];
    }] 
    .injectObjectWeakly[self] 
    .subscribeNext[(id)^(RACTuple *t) {
        GHDLoginViewController *self = t.last;
        self.loginFailedHidden = NO;
        NSLog(@"error logging in: %@", t.first);
    }] run];

I abuse subscripting to do this. On the plus side it means no real nesting problems. On the downside it means you have to put (id) in front of any block and if you're not assigning you have to have something like the -run method which does nothing but silences a compiler warning about side effects. Tiny bit hacky (requires some proxy stuff) but doable (at least on 10.7 and 10.8)