D1 -> D2

[Denis Koroskin]

On Thu, 18 Nov 2010 22:39:31 +0300, Walter Bright  
<newshound2 at digitalmars.com> wrote:

> Denis Koroskin wrote:
>>  From my experience, a bigger issue is that
>>  version (D2) {
>>    /* some D2 only code involving const etc */
>> }
>>  simply won't compile in D1, because even if it's D2-only the code  
>> needs to be correct D1 code as well.
>
> I agree that's an issue. Currently, the only way to deal with this is  
> one of:
>
> 1. Minimize the differences, and maintain two copies of the source code.  
> Using the (rather fabulous) meld tool (available on Linux), the merging  
> is pretty easy. I use meld all the time to, for example, merge  
> differences in the code base between dmd1 and dmd2.
>
> 2. Isolate the code that is different into different files, which  
> minimizes the work involved in (1).
>
> 3. Use string mixins and the token string literal form.
>
>
> I've also found that using the string alias rather than char[] does  
> account for an awful lot of the differences.

All these are ugly.