[swift-evolution] Remove (!) logical negation operator

[Marc Knaup]

I'm uncertain but it's definitely worth considering.

I also think that it's weird at the moment since in most cases the
exclamation mark is now something dangerous.
I also had a couple of bugs in my code because the operator is too easy to
miss and the negation was not or no longer intended.

On Tue, Dec 15, 2015 at 3:11 PM, Bruno Berisso via swift-evolution <
swift-evolution at swift.org> wrote:

> Hello,
>
> I'm really used to negate logical expressions with this operator but it
> never feels confortable to me. If I need to negate some complex expression
> sometimes I prefer to write a temporal variable and then negate that with
> *!* because I fear than others, or myself, could overlook it and cause
> confusion.
>
> Now that Swift use the same operator to force the unwrap of optional
> values it becomes even worse.
>
> Consider this examples:
>
> if someOptionalValue != nil {
>     ...
>     if !(otherBoolValue && someOptionalValue! > 0) {
>         ...
>     }
> }
>
> Or even worse, what happen when negating Optional<Bool> values?
>
> //Best case
> if let value = optionalBool where !value {
>     ...
> }
>
> //Worse case
> if !optionalBool! {
>     ...
> }
>
> Now what happen with this examples if we instead use a *not* operator:
>
> if someOptionalValue != nil {
>     ...
>     if not (otherBoolValue && someOptionalValue! > 0) {
>         ...
>     }
> }
>
> if let value = optionalBool where not value {
>     ...
> }
>
> if not optionalBool! {
>     ...
> }
>
> I'm not sure if *not* is the right path here but I really want to improve
> the *!* to something more clear at a glance and that doesn't have
> different behaviour depending where it appears in an expression.
>
> Thanks,
>
> _______________________________________________
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> swift-evolution at swift.org
> https://lists.swift.org/mailman/listinfo/swift-evolution
>
>
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