Closure arguments referenced by position inside nested closure in swift

2018-06-11 01:30:26

I have this piece of code which works fine:

var discoverEvents = events.map { event in
   userEvents.find { $0.eventID == event.eventID } ?? event
}

I wonder if there is any way to reference event by position inside find somehow like that:

var discoverEvents = events.map { userEvents.find { $$0.eventID == $0.eventID } ?? $0 }

to make it one-liner?

No, it's not possible. The inner $0 shadows the outer one, and there is no other way to refer to the $0 in the outer scope.

As @DavidBerry mentions, that syntax is intended for short anonymous functions. Things could get very confusing otherwise.

链接地址: http://www.djcxy.com/p/31786.html