I came across this line in production

let animated = presentedViewController == nil && route.animateTransition == false ? false : true

It’s more confusing than you’d expect. My initial thought is that it was equivalent to

let animated3 = (presentedViewController == nil && route.animateTransition) == false ? false : true

but that ending ) is out of place. Everything before a ternary operator will be executed before the remaining cases. So it’s actually

let animated4 = (presentedViewController == nil && route.animateTransition == false) ? false : true

Still not very readable. The next clue to break this down is that ? false : true is very long-hand for !. So that statement is equivalent to

let animated5 = !(presentedViewController == nil && route.animateTransition == false)

It’s really hard to keep on breaking down this statement until you take a step back and try to guess at what the author was trying to achieve. It seems like you would want something to be animated if route.animateTransition is true or if the presented controller exists. This could be animating a dismissal of a controlller or something like that.

Eventually, you can simplify it down to

let animated6 = presentedViewController != nil || route.animateTransition

It’s ~1000x more readable and much more clearly expresses the author’s intent. Here is the Gist with some of the intermediate steps taken out.