> On Jan 2, 2018, at 10:26 PM, Kelvin Ma via swift-evolution > <swift-evolution@swift.org> wrote: > > > > On Tue, Jan 2, 2018 at 11:45 PM, Nevin Brackett-Rozinsky via swift-evolution > <swift-evolution@swift.org <mailto:swift-evolution@swift.org>> wrote: > On Tue, Jan 2, 2018 at 9:07 PM, Jordan Rose via swift-evolution > <swift-evolution@swift.org <mailto:swift-evolution@swift.org>> wrote: > [Proposal: > https://github.com/apple/swift-evolution/blob/master/proposals/0192-non-exhaustive-enums.md > > <https://github.com/apple/swift-evolution/blob/master/proposals/0192-non-exhaustive-enums.md>] > > Whew! Thanks for your feedback, everyone. On the lighter side of > feedback—naming things—it seems that most people seem to like '@frozen', and > that does in fact have the connotations we want it to have. I like it too. > > More seriously, this discussion has convinced me that it's worth including > what the proposal discusses as a 'future' case. The key point that swayed me > is that this can produce a warning when the switch is missing a case rather > than an error, which both provides the necessary compiler feedback to update > your code and allows your dependencies to continue compiling when you update > to a newer SDK. I know people on both sides won't be 100% satisfied with > this, but does it seem like a reasonable compromise? > > The next question is how to spell it. I'm leaning towards `unexpected case:`, > which (a) is backwards-compatible, and (b) also handles "private cases", > either the fake kind that you can do in C (as described in the proposal), or > some real feature we might add to Swift some day. `unknown case:` isn't bad > either. > > I too would like to just do `unknown:` or `unexpected:` but that's > technically a source-breaking change: > > switch foo { > case bar: > unknown: > while baz() { > while garply() { > if quux() { > break unknown > } > } > } > } > > Another downside of the `unexpected case:` spelling is that it doesn't work > as part of a larger pattern. I don't have a good answer for that one, but > perhaps it's acceptable for now. > > I'll write up a revision of the proposal soon and make sure the core team > gets my recommendation when they discuss the results of the review. > > --- > > I'll respond to a few of the more intricate discussions tomorrow, including > the syntax of putting a new declaration inside the enum rather than outside. > Thank you again, everyone, and happy new year! > > Jordan > > > +1 to warning instead of error > +1 to unknown/unexpected case > +1 to “@frozen” or any other reasonable spelling, they are all fine by me. > > +1 to “@tangled” because abi is complicated
+1 to “@moana” because these are all just Disney movies > > > The one remaining problem to solve is making sure multi-module apps can leave > out the unknown/unexpected case on enums from modules which are part of the > app itself and thus cannot be updated independently of it. John McCall’s > version-locking plan sounds promising, though we should explore the available > options before finalizing a course. > > Perhaps we need a concept of submodules, or supermodules, or some other way > to demarcate the boundaries of a resilience domain. > > Nevin > > i would support a proper submodule system over some verson-locking system > that only the most advanced users will probably know about. i think modules > should be one level higher than what they’re currently being used for right > now for lack of a better alternative (one application should never have to > define more than one capital M Module). submodules shouldn’t be that hard to > implement, though the submodule names should be part of ABI to avoid name > mangling problems > > _______________________________________________ > swift-evolution mailing list > swift-evolution@swift.org <mailto:swift-evolution@swift.org> > https://lists.swift.org/mailman/listinfo/swift-evolution > <https://lists.swift.org/mailman/listinfo/swift-evolution>
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