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Explain Optional Chaining

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Without going into too much detail, mention optional chaining so it's
not confusing that there is a question mark suffix (it's not currently
mentioned anywhere on the page).
This commit is contained in:
Keito Uchiyama 2015-01-20 14:52:31 -08:00
parent 6915f5bfd0
commit 7a55b4a9b1
1 changed files with 4 additions and 1 deletions
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@ -446,6 +446,9 @@ class MyShape: Rect {
func grow() { func grow() {
sideLength += 2 sideLength += 2
// Place a question mark after an optional property, method, or
// subscript to gracefully ignore a nil value and return nil
// instead of throwing a runtime error ("optional chaining").
if let allow = self.delegate?.canReshape?() { if let allow = self.delegate?.canReshape?() {
// test for delegate then for method // test for delegate then for method
self.delegate?.reshaped?() self.delegate?.reshaped?()