We already don't have a .last on CollectionType and nobody's been complaining about that. Besides, sequences don't necessarily even terminate.
-Kevin Ballard On Wed, Dec 30, 2015, at 04:01 PM, Daniel Duan wrote: > Users who don’t get the single-pass nature of SequenceType may expect > a .last as well. > >> On Dec 30, 2015, at 3:57 PM, Kevin Ballard via swift-evolution <swift- >> [email protected]> wrote: >> >> It's sometimes useful to get the first element of a sequence. To that >> end I'd like to propose >> >> extensionSequenceType { /// Returns the first element of >> `self`, or `nil` if `self` is empty. /// - Complexity: O(1) var >> first: Self.Generator.Element? { var gen = generate() return >> gen.next() } } >> >> I think it makes sense to add this property to the definition of >> SequenceType as well, so various sequences can override it to avoid >> constructing a generator. >> >> With this added to SequenceType, we can remove it from >> CollectionType, as the behavior will be the same. >> >> -Kevin Ballard >> >> _______________________________________________ >> swift-evolution mailing list [email protected] >> https://lists.swift.org/mailman/listinfo/swift-evolution
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