RFC #10: Should bitmask enums be added

[ProCode-Software]

These would allow for multiple enum items to be applied as a single value, with efficient O(1) item detection. Algebraic enums or items with parameters will be allowed.

• Example of bitmask types in Go:

  typeMyEnumuint8const (
  Option1MyEnum=1<<iotaOption2Option3
  )
  varmyValueMyEnum=Option1|Option3// Check for an option
  (myValue&Option3) !=0// Assign an optionmyValue|=Option2// Remove an optionmyValue &^= Option1// JavaScript: myValue &= ~Option1

• For Klar:

  @flag // or '@flags'
  type MyEnum {
  .option1
  .option2
  .option3
  }
  myValue := MyEnum(.option1, .option3)
  myOpts: [MyEnum] := [.option1, .option3]
  myValue := MyEnum(myOpts...)
  // Possible approaches for checking
  myValue.has(.option3)
  (.option3 in myValue)
  // Possible approaches for setting
  myValue.set(.option2, true) // Mutating
  myValue.set(.option2) // `true` as a default param
  myValue = myValue.with(.option2) // Non-mutating
  myValue = MyEnum(myValue..., .option2)
  myValue += .option2
  // Possible approaches for removing
  myValue.set(.option1, false) // Mutating
  myValue = myValue.without(.option1, false) // Non-mutating
  myValue -= .option1
  

• To consider: If items with parameters are allowed, how can they be checked?