I accept the motivation for this change, although I would mention that: - in 2.5 years on a ~200k lines of Swift project - we've seen a plenty of instances of `flatMap` used where `map` would have been sufficient, but - we've never burned time on tracking down the sort of compiler issue described by the author in the Motivation. As I say, the argument is fair, but I am questioning how frequently this problem occurs.
I can't speak to the previous attempts to solve this problem, but I'd add my voice to anyone advocating solving this by having a compiler warning when `flatMap` is used redundantly(?). If this proposal were to be accepted, I'd also question the choice of `filterMap` as a name. This name is presumably shorthand for `filterNonesAndMap`, which conveniently ignores the following: - `flatMap` may be used on a sequence-of-sequences to flatten our to a single-dimensional sequence. - `flatMap` may be used on other 'box' types, e.g. on an optional: `Optional <String>("foo").flatMap { .some($0 + "bar") }` or on the common `Result` type. Any re-naming of one `flatMap` should take these other uses into account, as they share conceptual details. Thanks, Sam
_______________________________________________ swift-evolution mailing list swift-evolution@swift.org https://lists.swift.org/mailman/listinfo/swift-evolution