Swift 2.0 - ReactiveCocoa API changes

|> -> .

Aside from converting all usages of |> to simply . ( - much better! we now have code completion! 🎉), a few other notable things tripped me up when switching to the Swift 2.0 api:


catch is now a reserved word in Swift 2.0, so you should simply replace all usages with flatMapErrors - it's the same.


Secondly, the compiler now seems to have problems identifying which default parameter it should use when you pass a closure to start:. Previously it was common to use the following shorthand:

producer.start { value in ... }`

Where we really meant was:

producer.start(next: {value in ...})

The method signature of start: is really:

start(error error: (E -> ())? = nil, completed: (() -> ())? = nil, interrupted: (() -> ())? = nil, next: (T -> ())? = nil) -> Disposable

The Swift 2.0 compiler (Xcode 7 b6, at least) now makes a different decision about what we're trying to do. Due to the fact that we're passing a single block parameter, it now seems to assume that we want to call the start(sink: Event<T, E>.Sink) method instead. This is our clue that something's not right, as we start seeing that our blocks are being passed variables of type Event<YourType, NoError> rather than the expected type.

The solution is easy: either just be clearer about what you're calling by reinstating the next: parameter name:

producer.start(next: {value in ...})`

.. or provide more type information in your closure, to help the poor compiler out:

producer.start { (displayableAnnotations: YourType) in ... }


We no longer use .put(x) to set the value on a MutableProperty type - .value is now settable, so we just get and set .value directly. This is probably good, though I liked the separation before - it made it more obvious that MutableProperty also dealt in events. But like I say, it's probably simpler now.