D_Version2 problem

[David Ferenczi]

Robert Fraser wrote:

> David Ferenczi wrote:
>> == Quote from Sergey Gromov (snake.scaly at gmail.com)'s article
>>> Sun, 18 Jan 2009 22:28:12 +0100, Hoenir wrote:
>>>> The D_Version2 version identifier doesn't work properly for me.
>>>> Tried compiling with dmd 1.039. D_Version2 is set even if I pass -v1 to
>>>> it.
>>>>
>>>> Is this a bug or am I doing something wrong?
>>> Works for me.
>>> It's hard to tell if you're doing something wrong until you post your
>>> test code.
>>> ----8<------ test.d
>>> version(D_Version2)
>>> {
>>>   pragma(msg, "v2");
>>> }
>>> else
>>> {
>>>   pragma(msg, "v1");
>>> }
>>> ----8<------
>>>> dmd -c test.d
>>> v1
>> 
>> The behaviour is a bit ambigous, since in compile time every version
>> block gets interpreted! So you cannot put D2 only code in the
>> version(D_Version2) {} block, if you want to compile your source with D1.
>> 
>> I don't know if it's a bug or a feature.
>> 
>> Regards,
>> David
> 
> This has been discussed many times over. It's a "feature" according to
> Walter, and there's some sense to it (since D code is supposed to be
> parseable without doing semantic analysis, and versions can require
> arbitrary ammounts of semantic analysis (like CTFE) to determine). If
> you want to have D2 code you need to use a mixin:
> 
> version(D_Version2) {
>      mixin("const(char)[] x;");
> } else {
>      char[] x;
> }
> 
> Note that the -v1 switch reverts to the (rather arbitrary) D version
> 1.00, while new D features were being added through (I think) 1.014.

Many thanks for your answer. I should have missed this discussion. I still
think, that it should be possible to skip the code blocks, which are behind
not met version conditons. Maybe an extra compiler switch?

Do I presume correctly that in case of using a mixin the literal won't be
interpreted, and that's why it doesn't cause any problem?