C like macro is useful

[downs]

davidl wrote:
> consider:
> 
> version(v1)
> {
>   enum e
>   {
>      a,
>      b
>   }
> }
> else
> {
>   enum e
>   {
>      a,
>      b,
>      c
>   }
> }
> 
> If my enum contains a lot of stuffs.... D version becomes a disaster.
> 
> 
> consider:
> version(v1)
> {
>   if ( cond1() && cond2() && a==b)
>   {
>      //blah
>   }
> }
> else
> {
>   if ( cond1() && cond2() && a!=b)
>   {
>      //blah
>   }
> }
> 
> in C you can do it
> 
> if ( cond1() && cond2() &&
> #ifdef v1
>      a==b
> #else
>      a!=b
> #endif
>    )
> {
>    // blah
> }
> 
> 
> Any good and practical way to solve these?
> 
> 
> 
> 

version(v1) auto cond = a == b;
else auto cond = a != b;

What's the problem again?