[stdlib] SR-361: Implement SE008: Add Lazy flatMap for Seq of Optionals #2461
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https://bugs.swift.org/browse/SR-361 Adds required LazyFilterRandomAccessCollection and the flatMap extensions.
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@russbishop Thank you!
This wasn't a part of the proposal. This type was intentionally omitted because moving an index in a filtered collection can't be implemented in O(1) -- moving an index n steps requires evaluating the predicate n times. |
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| /// Returns a `LazyMapSequence` containing the concatenated non-nil | ||
| /// results of mapping transform over this `Sequence`. The elements of | ||
| /// the result are computed lazily, each time they are read. |
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The summary of the doc comment should be a single sentence. CC @natecook1000
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The second sentence could just be removed, since that's covered by the Lazy... type of the return.
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@swift-ci Please test |
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@gribozavr That makes sense now that I think about it. It seems like the overload for I'll also fixup the tests and pull in that dataset. |
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@gribozavr I reverted the |
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@russbishop Thank you! |
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@swift-ci Please test |
| /// - Parameter transform: A closure that accepts an element of this | ||
| /// sequence as its argument and returns an optional value. | ||
| @warn_unused_result | ||
| public func flatMap<U>( |
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Could you change U to ElementOfResult?
If you feel like doing so, could you also change the names of generic type parameters in the eager flatMap overloads (stdlib/public/core/SequenceAlgorithms.swift.gyb) to SegmentOfResult and ElementOfResult?
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Yeah, that's no problem
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@russbishop Thank you! The CI failures are unrelated. I just have two style comments, and we should be good to merge your PR. |
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@gribozavr Pushed rename of generic arguments |
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@swift-ci Please test and merge |
What's in this pull request?
LazyFilterRandomAccessCollectionto the generated boilerplateflatMap<U>(transform: (Element) -> U?)extensions for sequences and the various kinds of collectionsResolved bug number: (SR-361)
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