Hi Mike, 2017-10-15 14:55 GMT+02:00 Mike Kluev <mike.kl...@gmail.com>:
> On 15 October 2017 at 13:35, Geordie Jay <geo...@gmail.com> wrote: > >> Also we're not talking about whether the Bool itself is discardable. For >> example, it makes no sense to write: >> >> *let something: discardable Bool = true* >> > > you can't write this either: > > let something: inout Bool = true > > that doesn't mean "inout" should be "@inputOutput" before the parameter > name in function signature. > This is a different case: inout is an annotation on argument types (of which there can be many). > > my litmus test is: "if we did it now in swift 0.0 what would we do". > discardable before type passes this test, @discardableResult before > function doesn't. > I don't understand what you're saying here. "Now in swift 0.0"? The first public version of Swift had this same functionality in its same form, with the name @warn_unused_result. The current version is just reversed, which to me is a logical change. > > >> There has been some discussion of "throws" as a keyword. If anything I >> think that is something that is in more need of change. I've always read it >> (frustratingly) as e.g. "func throws Bool", which it doesn't, it throws an >> Error. >> > > indeed. that's why "throws Bool" is wrong and if anything, i am advocating > for: > > throwing func foo() -> Bool > I personally like that syntax, because that's exactly how I *talk* about such a function. "oh that's a throwing function so you need to call it with *try*". As an extension to that, I'd also say "you can call that function without a preceding variable assignment because it has a discardable result". I would never say "this function returns a discardable boolean" because that just doesn't match my mental model of what's going on. To me, it's the *function* whose return value can be discarded — in theory it has nothing to do with the result itself. But it's quite possible I'm in the minority here. - Geordie
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