foreach with enum

[Robert Fraser]

Thomas Mader Wrote:

> I am just porting some of my little Java programs to D to get comfortable with the langugage and realized that I cannot use foreach with Enums.
> In Java I can do:
> enum Color { Kreuz, Pik, Herz, Karo }
> for(Color color : Color.values()) {}
> 
> AFAIK thats not possible in D yet.

Hi Thomas,

D enums are effectively just collections of integral constants, optionally with a namespace. Java enums are a lot more powerful (though I think they go a little bit overboard -- if you're adding methods to your enum members, isn't it about time you made them a true class hierarchy?).

I created a mixinable template generating an enum-like struct that overcomes many of the shortcomings of D's enum (there's a "toString" method to get the name, a "members" static method to get a collection of all the members (so you can loop through them just fine), and it's possible to check if a particular member exists by using an is expression). I've also created a "BitSwitch" template that's a bit harder to work with, but with the same advantages. They're just structs with a single uint member, so they're no less efficient than enums are now.

I can post both of them if you want, but others have probably come up with (better) implementations (I think someone on learn mentioned they hand done something similar).