Proposal: !! operator

[aaulmer]

In the same fashion of the ++ or -- operators, there should be a !! operator for the cases when we want to flip a boolean without having to self-reassign it. This is especially nice in practice when using long camel-cased variable names. Because instead of looking for a ! in the midst of a long code line, we can much more easily identify !! at the end and recognize its importance.

bool longCamelCasedVariableName = false;

// ... later in code ...
longCamelCasedVariableName = !longCamelCasedVariableName;

This instead would be written as:

bool longCamelCasedVariableName = false;

// .. later in code ...
longCamelCasedVariableName!!;

[KalleOlaviNiemitalo]

If it's just a bool, then you can already do this:

longCamelCasedVariableName ^= true;

[themeeman]

This is very much nothing like ++ and --. That would imply the -- was two negations.

[szalapski]

I would never want !! to flip a boolean; this would be very confusing to Javascript developers where it means something entirely opposite.

[canton7]

Don't forget that a ! suffix is used to suppress nullability warnings. !! looks like "really suppress nullability warnings".

[KalleOlaviNiemitalo]

Since #186, C# 7.2 also allows static void Toggle(ref this bool flag) { flag = !flag; }. That won't work on by-value properties though, unless #1677 (comment) is implemented.

[MgSam]

I'll one up you. I want a !!!! prefix operator that tells me when something is true. That way I can really be clear when I want something.

if (!!!!areThereCookies()) eatCookies();

[Thaina]

While I don't agree with syntax at all I think it is interesting reason for the feature

Maybe, what if we could write a shorthand like this?

bool longCamelCasedVariableName = false;

// .. later in code ...
longCamelCasedVariableName = !; // just symbol ! for shorthand the whole left side variable

someClass.someProperty.someValue.someBoolean = !; // also work with deep variable

[Flutterish]

If you shout at a boolean it will flip its..! ...value...