StaticMemberEnum.Generator 1.0.0

Static Property Enum Generator

Why

Enums are great, but often data has a fixed set of known values AND should allows for unknown values.

This can be accomplished with static members on a type. For example System.Drawing.Color. More examples and exploration is availabe here.

This comes with some disadvantages though, like not being able to list the known values without writing boilerplate for every type.

That's what this library solves. It uses the new C# 9 Source Generators to automattically add a .KnownValues() including all static members that have the same type as the containing declaration.

Example. Given

namespace Some.Namespace{
	[StaticMemberEnum]
	partial class GolfClubTypes{
		private readonly string _id;
		public GolfClubTypes(string id) => _id = id;
		public static GolfClubTypes Driver = new GolfClubTypes("Driver");
		public static GolfClubTypes Iron = new GolfClubTypes("Iron");
		public static GolfClubTypes Wedge = new GolfClubTypes("Wedge");
		public static GolfClubTypes Hybrid = new GolfClubTypes("Hybrid");
		public static GolfClubTypes Wood = new GolfClubTypes("Wood");
	}
}

The library generates

namespace Some.Namespace{
	partial class GolfClubTypes{
		public static IEnumerable<GolfClubTypes> KnownValues(){
			return new []{Driver, Iron, Wedge, Hybrid, Woood};
		}
	}
}

So that you can call

IEnumerable<GolfClubTypes> clubs = GolfClubTypes.KnownValues();

A few potential gotchas

• The member enum definition has to be partial because source generators behave about the same as adding new sources files.
• This generator currently doesn't work on nested classes. It would require the whole hierarchy of classes to be partial. That seems smelly to me, so I decided not to support it. Let me know in the github issues if you have reasons I should change my mind.
• Classes won't have value-based equality behavior by default, and structs don't define == by default. I recommend using records.
  • You can use a generator like Generator.Equals if you still want a class or struct
  • Structs should only be used with very small values (under 16 bytes). See the offical explanation