https://www.cqse.eu/en/blog/living-in-the-ifdef-hell/

Another voice on what is wrong with the snarl of #ifdef's.

On 10/29/2015 3:18 PM, Walter Bright wrote:
> https://www.cqse.eu/en/blog/living-in-the-ifdef-hell/
>
> Another voice on what is wrong with the snarl of #ifdef's.

Reddit: https://www.reddit.com/r/programming/comments/3qo79b/living_in_the_ifdef_hell/

On Thursday, 29 October 2015 at 22:18:11 UTC, Walter Bright wrote:
> https://www.cqse.eu/en/blog/living-in-the-ifdef-hell/
>
> Another voice on what is wrong with the snarl of #ifdef's.

how does this differ from static if and version(x) hell?

On 10/29/2015 3:23 PM, rsw0x wrote:
> On Thursday, 29 October 2015 at 22:18:11 UTC, Walter Bright wrote:
>> https://www.cqse.eu/en/blog/living-in-the-ifdef-hell/
>>
>> Another voice on what is wrong with the snarl of #ifdef's.
>
> how does this differ from static if and version(x) hell?

We advise people not to use static if to do what version(x) eschews, and suggest better alternatives.

On Thursday, 29 October 2015 at 23:10:38 UTC, Walter Bright wrote:
> On 10/29/2015 3:23 PM, rsw0x wrote:
>> On Thursday, 29 October 2015 at 22:18:11 UTC, Walter Bright wrote:
>>> https://www.cqse.eu/en/blog/living-in-the-ifdef-hell/
>>>
>>> Another voice on what is wrong with the snarl of #ifdef's.
>>
>> how does this differ from static if and version(x) hell?
>
> We advise people not to use static if to do what version(x) eschews, and suggest better alternatives.

Ha, I wish!

In fact, you are currently arguing for people to write *more* version statements over at the https://github.com/D-Programming-Language/dmd/pull/5231

 — David

On Thursday, 29 October 2015 at 23:14:26 UTC, David Nadlinger wrote:
> On Thursday, 29 October 2015 at 23:10:38 UTC, Walter Bright wrote:
>> We advise people not to use static if to do what version(x) eschews, and suggest better alternatives.
>
> Ha, I wish!
>
> In fact, you are currently arguing for people to write *more* version statements over at the https://github.com/D-Programming-Language/dmd/pull/5231

The idea is that you get rid of all of the &&ing and ||ing that tends to make #ifdefs really hard to follow and error-prone. And by having each version fully separate, changing one version won't break another.

Now, that comes at the cost of forcing you to duplicate a lot of code, which almost everyone other than Walter thinks is worse than the risks associated with merging similar versions together, but as far as I can tell, Walter is completely consistent in his arguments.

- Jonathan M Davis

On 10/29/2015 4:14 PM, David Nadlinger wrote:
> In fact, you are currently arguing for people to write *more* version statements
> over at the https://github.com/D-Programming-Language/dmd/pull/5231

I presented several ways to avoid using complex version statements.

I might add that over time, I'd been removing #if's and #ifdef's from the dmd front end source code. The results were very satisfactory - the code was easier to read, understand and maintain. It also made running magicport on the code practical.

I've been slowly doing the same to the back end.

On 2015-10-30 03:01, Walter Bright wrote:

> I might add that over time, I'd been removing #if's and #ifdef's from
> the dmd front end source code. The results were very satisfactory - the
> code was easier to read, understand and maintain. It also made running
> magicport on the code practical.

The DMD source code contained #ifdef's inside expressions, which is quite a difference compared to "or" and "and" in "static if".

-- 
/Jacob Carlborg

On Thursday, 29 October 2015 at 23:10:38 UTC, Walter Bright wrote:
> On 10/29/2015 3:23 PM, rsw0x wrote:
>> On Thursday, 29 October 2015 at 22:18:11 UTC, Walter Bright wrote:
>>> https://www.cqse.eu/en/blog/living-in-the-ifdef-hell/
>>>
>>> Another voice on what is wrong with the snarl of #ifdef's.
>>
>> how does this differ from static if and version(x) hell?
>
> We advise people not to use static if to do what version(x) eschews, and suggest better alternatives.

The same thing can be said about #ifdef. Conventional wisdom in C++ says there's better ways, but the abuse compiles thus continually abused.

On 31/10/2015 12:01 AM, Jacob Carlborg wrote:
> On 2015-10-30 03:01, Walter Bright wrote:
>
>> I might add that over time, I'd been removing #if's and #ifdef's from
>> the dmd front end source code. The results were very satisfactory - the
>> code was easier to read, understand and maintain. It also made running
>> magicport on the code practical.
>
> The DMD source code contained #ifdef's inside expressions, which is
> quite a difference compared to "or" and "and" in "static if".
>

Yes, this was the major problem with converting the #ifdefs, not conditions ||ed together.  If D allowed oring versions together then version would have been a lot more useful in DDMD.