Really? My observation from a quick test is that "a? = b" assigns b to a if a already has a value, or does nothing if it's nil. This is sort of the opposite of what's being proposed, which is that "a ?= b" should assign to a only if it does NOT have a value. On Wed, Jan 25, 2017 at 9:33 AM Joe Groff via swift-evolution < [email protected]> wrote:
> > > On Jan 25, 2017, at 8:40 AM, Nichi Shin via swift-evolution < > [email protected]> wrote: > > > > I’d like to propose a new operator for optional assignment in Swift. > > > > The idea is that by using this operator (e.g. by doing a ?= b), the > optional on the right would be assigned to the variable on the left only > when it has something to assign (i.e. when it's not nil). > > `a? = b` already does this. Maybe we need a fixit to make that more > apparent, though. > > -Joe > > > > > The implementation could be something as follows: > > > > /// Optional Assignment Operator > > infix operator ?=: AssignmentPrecedence > > > > func ?=<T>(left: inout T, right: T?) { > > if right != nil { > > left = right! > > } > > } > > > > func ?=<T>(left: inout T?, right: T?) { > > if right != nil { > > left = right > > } > > } > > > > I hope you will consider adding this on a future release of this great > programming language. > > > > Kind regards, > > N. S. > > _______________________________________________ > > swift-evolution mailing list > > [email protected] > > https://lists.swift.org/mailman/listinfo/swift-evolution > > _______________________________________________ > swift-evolution mailing list > [email protected] > https://lists.swift.org/mailman/listinfo/swift-evolution >
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