[swift-evolution] Proposal: Deprecate optionals in string interpolation

Jeremy Pereira jeremy.j.pereira at googlemail.com
Thu May 19 11:07:05 CDT 2016


This seems to me like crippling string interpolation just because sometimes we make mistakes. 99% of the time, if I interpolate an optional, it’s because I want it that way. I don’t want to have to put up with a warning or write the same boilerplate 99% of the time just to flag up the 1% more easily. Sorry.

> On 18 May 2016, at 19:50, Krystof Vasa via swift-evolution <swift-evolution at swift.org> wrote:
> The string interpolation is one of the strong sides of Swift, but also one of its weaknesses. 
> It has happened to me more than once that I've used the interpolation with an optional by mistake and the result is then far from the expected result. 
> This happened mostly before Swift 2.0's guard expression, but has happened since as well.
> The user will seldomly want to really get the output "Optional(something)", but is almost always expecting just "something". I believe this should be addressed by a warning to force the user to check the expression to prevent unwanted results. If you indeed want the output of an optional, it's almost always better to use the ?? operator and supply a null value placeholder, e.g. "\(myOptional ?? "<<none>>")", or use myOptional.debugDescription - which is a valid expression that will always return a non-optional value to force the current behavior.
> Krystof
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