How do you deal with "flag" enums in Kotlin? Let's...

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[Sylvain Patenaude]

How do you deal with "flag" enums in Kotlin? Let's say I have flags 1,2,4,8 in my enum and from parsing some data, I obtain 5 (1 and 4 combined). How do I convert that 5 back into some enum value? In .NET, you have these "flag" enums and they are quite useful.

[Tesserakt]

In kotlin this isn't implemented, I think. I use my own implementation. ValuedEnum holds current flag number. IValued represents enum entry with flag. As in C# you can intersect, union, etc it.
https://github.com/ITesserakt/diskordin/blob/master/src/main/kotlin/org/tesserakt/diskordin/util/enums/IValued.kt
https://github.com/ITesserakt/diskordin/blob/master/src/main/kotlin/org/tesserakt/diskordin/util/enums/ValuedEnum.kt

[Alowaniak]

Use an EnumSet?

[Tesserakt]

Enum set doesn't allows to clearly add one flags to another flags and also it is very easy to confuse flag codes, add non-flag enum to normal enum,

[Alowaniak]

Not sure how it's easy to confuse flag codes if the whole point is you don't use any codes
Except for the parsing,writing I guess, but you should only want to do that at most one place (if you really need to save bytes or w/e)
Also "add non-flag enum to normal enum" sounds like you shouldn't mix different types of enums? The EnumSet is generic and thus can only contain enum instances of a certain type

[Tesserakt]

I'm sure with you. In general cases it isn't quite useful. But ye, there are situations when flags explicitly being. It is some API (discord 😄), low-system mechanics, etc.

[Sylvain Patenaude]

Is EnumSet multiplatform though? I skimmed through it, but it looked like it was Android specific.

[Tesserakt]

It's java specific class

[Matteo Mirk]

I would go with EnumSet too, otherwise you can try Java BitSet