One practical implication of treating Sequence as infinite is in lazy filter. If you pass Sequence, but not Collection, to lazy filter, it will guarantee to iterate it only once. If it's a collection, it will feel free to iterate it twice.
So one benefit of single-pass sequences is assumptions about behaviour of an API: if it can work with sequences, then it will only iterate them once. _______________________________________________ swift-evolution mailing list [email protected] https://lists.swift.org/mailman/listinfo/swift-evolution
