Bruce Eckel gives a reason in Thinking in C++: In older versions of C++, static const was not supported inside classes. This meant that const was useless for constant expressions inside classes. However, people still wanted to do this so a typical solution (usually referred to as the “enum hack”) was to use an untagged … Read more
In Swift 1: stop.withUnsafePointer { p in p.memory = true } In Swift 2: stop.memory = true In Swift 3 – 4: stop.pointee = true
This question suits one of my old notes. I hope this illustration helps:
It’s perfectly legal to have an enum declared inside an interface. In your situation the interface is just used as a namespace for the enum and nothing more. The interface is used normally wherever you use it.
You don’t necessary need a custom JsonConverter you can use the built in StringEnumConverter with the combination of the EnumMemberAttribute (from the System.Runtime.Serialization assembly). Without the EnumMemberAttribute it uses the enum names so Artist, Contemporary, etc so you need to change the names with it to your A,C, etc value. But it is not the … Read more
Here is an example of adding attributes to scala enums by extending the Enumeration.Val class. object Planet extends Enumeration { protected case class Val(val mass: Double, val radius: Double) extends super.Val { def surfaceGravity: Double = Planet.G * mass / (radius * radius) def surfaceWeight(otherMass: Double): Double = otherMass * surfaceGravity } implicit def valueToPlanetVal(x: … Read more
This is actually in my opinion an appropriate use case for 2.10 macros: you want access to information that you know the compiler has, but isn’t exposing, and macros give you a (reasonably) easy way to peek inside. See my answer here for a related (but now slightly out-of-date) example, or just use something like … Read more
This is a nice challenge to have and solving it will definitely give you some insight into functional programming. The solution for such problems in functional languages is usually reduce (often called fold). I will start with a short answer (and not a direct translation) but feel free to ask for a follow up. The … Read more
To add to @StackedCrooked answer, you can overload operator++, operator– and operator* and have iterator like functionality. enum Color { Color_Begin, Color_Red = Color_Begin, Color_Orange, Color_Yellow, Color_Green, Color_Blue, Color_Indigo, Color_Violet, Color_End }; namespace std { template<> struct iterator_traits<Color> { typedef Color value_type; typedef int difference_type; typedef Color *pointer; typedef Color &reference; typedef std::bidirectional_iterator_tag iterator_category; }; … Read more
You can use an array or hash for this purpose (in your environment.rb): OPTIONS = [‘one’, ‘two’, ‘three’] OPTIONS = {:one => 1, :two => 2, :three => 3} or alternatively an enumeration class, which allows you to enumerate over your constants as well as the keys used to associate them: class Enumeration def Enumeration.add_item(key,value) … Read more