const classafFancom::Flag

A Flag represents many states by setting and clearing bits on a Int.

Using Ints as flags is still valid, but the Flags class gives superior debugging info. An example Flags class:

const class MyFlags : Flags {
  static const MyFlags one     := MyFlags(1, "one")
  static const MyFlags two     := MyFlags(2, "two")
  static const MyFlags three   := MyFlags(3, "three")
  static const MyFlags four    := MyFlags(4, "four")

  new make(Int flag, Str? name) : super(flag, name) { }
  new makeFromVariant(Variant variant) : super(variant) { }	
}

Set and clear bits by using + and - operators:

(MyFlags.two + MyFlags.two) .toStr  --> two
(MyFlags.two - MyFlags.four).toStr  --> two

Multiple flags may be set:

(MyFlags.one + MyFlags.four).toStr  --> one|four
(MyFlags.two + MyFlags.four).toStr  --> two|four

Flags are automatically coalesced:

(MyFlags.one + MyFlags.three) .toStr  --> three 

Unknown flags are presented as numbers:

(MyFlags(16))               .toStr  --> (18)
(MyFlags(10))               .toStr  --> two|(8)
(MyFlags(27))               .toStr  --> three|(8)|(16)

Every Flags subclass needs to declare the following ctor to fulfil the variant surrogate contract:

new makeFromVariant(Variant variant) : super(variant) { }