Am 08.04.2014 21:08, schrieb Andrei Alexandrescu:
(moving http://goo.gl/ZISWwN to this group)
On 4/7/14, 3:41 PM, w0rp wrote:
Yeah, I've seen this happen before. I think we could actually introduce
a little more type safety on enums without a great deal of breakage. It
would be nice to have a final switch give you as much of a guarantee
about what it's doing as it can.
People use enums for things such as:
1. A discrete set of categorical values:
enum State { initial, waiting, running, done }
That's probably the most common use, and the one that prompted the
moniker "enum(eration)".
This seems to be exactly the use case for which C++ enum class has been
designed. But there is one major flaw in C++ enum class. Usually if you
have a discrete set you want to use it to index into an array.
E.g.
enum ShaderType { Vertex, Geometry, Pixel };
Shader[ShaderType.max] shaders;
shaders[ShaderType.Vertex] = new Shader();
In C++ you can't index arrays using a enum class without casting them
first. This is in my opinion a major problem. We should not make the
same mistake, in case we redesign enums.
Kind Regards
Benjamin Thaut
