Ternary-ish operators without an else clause

??.swift

infix operator ?? : Branching

precedencegroup Branching {
	associativity: left
	lowerThan: ComparisonPrecedence // also accounts for NilCoalescingPrecedence
}

/// Ternary-y operators without an else clause
///
/// - Parameter lhs: The Boolean value to evaluate
/// - Parameter rhs: A closure to run if the lhs evaluates to true
public func ?? (lhs: Bool, rhs: @autoclosure () -> Void) {
	if lhs { rhs() }
}

examples.swift

true ?? print("hi") // prints "hi"

2 + 2 == 5 ?? print("lol") // doesn't laugh

func blorp(_ x: Operation?) {
	x?.cancel()
	x?.isCancelled ?? false ?? gogogo(x!)
}

func gogogo(_ x: Operation) {
	x.main()
}

blorp(BlockOperation(block: { print("1a2a3a") })) // prints 1a2a3a
blorp(nil) // does nothing