Swift import C enum behavior

import-c-enum.swift

/*
  For the sake of Swift import there are 3 types of enums:

  1. A non-overlapping, non-option set enum
  2. A non-overlapping option set
  3. An overlapping option set
*/

/// C enum of type 1: A non-overlapping, non-option set
///
///   enum Foo {
///     A,
///     B
///   }
///
/// Imports in Swift to:
enum Foo {
  case A
  case B
}

/// C enum of type 2: A non-overlapping option set
///
///   enum Foo {
///     A = 1,
///     B = 2
///   }
///
/// Imports in Swift to:
enum Foo: Int {
  case A = 1
  case B = 2
}

/// This allows the developer to define the OptionSetType protocol definition
extension Foo: OptionSetType {
  init(rawValue: Int) {
    self = Foo.init(rawValue: rawValue) ?? Foo.A // Or maybe Foo.B, developer discresion
  }
}

/// C enum of type 3: A overlapping option set
///
///   enum Foo {
///     A = 1,
///     B = 2,
///     C = 1
///   }
///
/// Imports in Swift to (existing behavior):
struct Foo: RawRepresentable, Equatable {
}

var FooA: Foo { get }
var FooB: Foo { get }
var FooC: Foo { get }