ios - RACObserve(), RAC() - how to set a BOOL value based on an NSString -

being reactivecocoa newbie, i'm hoping advice this:

i'm trying create dynamic form contains multiple field objects parsed xml file. each field can have muliple validation rules run against field's nsstring *value param.

for rac part of question-

inside each field object, want bind bool completed signal checks field's *value param against array of rules. far i've gotten here thinking:

@implementation field  self = [super init]; if (self) {      rac(self, completed) = [racobserve(self, value) filter:^bool(nsstring *fieldvalue) {         nslog(@"%s::self.completed = %d\n", sel_getname(_cmd), self.completed);  // trying watch values here, no luck          nslog(@"%s::fieldvalue = %@\n", sel_getname(_cmd), fieldvalue);  // same here, i'd able view `*value` here far no luck          return [self validatecurrentvalue]; // method checks value.length > 5      }]; } return self; 

the *value param has been bound view model (successfully) , gets updated each time textfield changes.

what i'm looking basic example or best-practice, code above crashes when run know i'm missing fundamental.

thanks all

-filter: passing values racobserve(self, value) through unchanged, if block returns yes. means you're trying set completed values of whatever type value is. that's bad®.

but news you're close!

instead of filtering, want transform. want take every value , map other thing. namely whether value passes validation. that, use -map::

rac(self, completed) = [racobserve(self, value) map:^(nsstring *fieldvalue) {     return @([self validatecurrentvalue]);     }];