On May 13, 2016, at 9:16 AM, Joe Groff via swift-evolution <[email protected]> wrote: >> This encourages the use of empty closures over optional closures, which I >> think is open for debate. In general I try to avoid optionals when they can >> be precisely replaced with a non-optional value. Furthermore, most Cocoa >> completion handlers are not optional. >> >> The alternative is to not do this, but encourage that any closure that could >> reasonably be empty should in fact be optional. I would then want Cocoa >> functions with void-returning closures to be imported as optionals to avoid >> "{ _ in }". > > +1. In general, I think we should allow implicit arguments, without requiring > the closure to use all the implicit $n variables like we do today. These > should all be valid: > > let _: () -> () = {} > let _: (Int) -> () = {} > let _: (Int, Int) -> Int = { 5 } > let _: (Int, Int) -> Int = { $0 } > let _: (Int, Int) -> Int = { $1 }
I agree, but I consider this to be an obvious bug in the compiler. I don’t think it requires a proposal. Unfortunately it is non-trivial to fix… -Chris _______________________________________________ swift-evolution mailing list [email protected] https://lists.swift.org/mailman/listinfo/swift-evolution
