“Flatten”, in the context here (flattening a Sequence of Optionals), only makes sense if you consider Optional as a sequence of zero or one elements. While such a sequence does act very similarly to an Optional, the fact remains that Optional is not a Sequence, and is generally not treated as one by any other part of the language. It fundamentally makes no more sense to “flatten" a Sequence of Optionals than it does to “flatten" an Optional of a Sequence.
In my mind, filter makes sense because I’m filtering out some of the results of the transformation operation before they get put into the resulting array. It’s a different kind of operation; not a map, but a filterMap. (Maybe filteringMap would be clearer?) The operation is not “map into a new array, then filter”. It’s “run this transformation for each item. If it produces something, keep it.” There’s no filter or compact that runs on the entire collection. -BJ > On Nov 14, 2017, at 7:50 AM, Tino Heth via swift-evolution > <swift-evolution@swift.org> wrote: > > >> Yeah but it seems clear from the return type so I am not sure that much >> confusion would really exist. > > > Afaics, there already is lots of confusion — that’s the reason for me to > write a sequence of posts in this topic, instead of an Optional ;-) > The word „flatten“ is a quite honest description, so I wonder why words like > filter, remove, ignoring or skipping should be used instead. > > „Compact“ would be less irritating, but I could imagine that it indicates > something like eliminating repeated occurrences. > > Tino > > (I’m quite close to attach a hand-drawn illustration of the flatMap process — > I don’t think you want that to happen ;-) > > _______________________________________________ > swift-evolution mailing list > swift-evolution@swift.org > https://lists.swift.org/mailman/listinfo/swift-evolution
_______________________________________________ swift-evolution mailing list swift-evolution@swift.org https://lists.swift.org/mailman/listinfo/swift-evolution
