How to implement this?

[Elvis]

On Monday, 10 June 2013 at 14:40:05 UTC, Kenji Hara wrote:
> On Monday, 10 June 2013 at 09:42:56 UTC, Elvis wrote:
>> class A
>> {
>>    enum TypeID = 1;
>> }
>> class B : A
>> {
>>    enum TypeID = 2;
>> }
>>
>> class C : A
>> {
>>    enum TypeID = 3;
>> }
>>
>> class D : B
>> {
>>    enum TypeID = 4;
>> }
>>
>> ...
>>
>>
>> Could anybody shed some light on how to make these TypeIDs 
>> auto increment at compile time?
>
> version(A)
> {
>     class A
>     {
>          enum TypeID = 1;
>     }
>
>     template IncrementTypeID(Class)
>     {
>         class IncrementTypeID : Class
>         {
>             enum TypeID = Class.TypeID + 1;
>         }
>     }
>     alias B = IncrementTypeID!A;
>     alias C = IncrementTypeID!B;
>     alias D = IncrementTypeID!C;
> }
> version(B)  // more generative way
> {
>     template MakeContinuousClasses(int endID)
>     {
>         static if (endID > 0)
>         {
>             mixin MakeContinuousClasses!(endID - 1);
>
>             enum className = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"[endID 
> - 1];
>             static if (endID == 1)
>                 enum baseClass = "";
>             else
>                 enum baseClass = " : " ~ 
> "ABCDEFGHIJKLMNOPQRSTUVWXYZ"[endID - 2];
>
>             import std.conv : to;
>             mixin("class "~className~baseClass~" { enum TypeID 
> = "~endID.to!string~"; }");
>         }
>     }
>     mixin MakeContinuousClasses!4;
> }
>
> // test case
> import std.traits;
> pragma(msg, A.TypeID, ", ", BaseClassesTuple!A);  // 1, (Object)
> pragma(msg, B.TypeID, ", ", BaseClassesTuple!B);  // 2, (A, 
> Object)
> pragma(msg, C.TypeID, ", ", BaseClassesTuple!C);  // 3, (B, A, 
> Object)
> pragma(msg, D.TypeID, ", ", BaseClassesTuple!D);  // 4, (C, B, 
> A, Object)
>
> Kenji Hara

Thank you, however both versions are not applicable, you need 
give them some type of orders manully in version A while class 
names are suppose to be more generic in real project other than 
just A to Z in version B.