Biggest Issue with D - Definition and Versioning

[Andrei Alexandrescu]

On 1/15/12 5:30 AM, Peter Alexander wrote:
> On 15/01/12 3:31 AM, Andrei Alexandrescu wrote:
>> 1. SIMD is not the top of the list. Two weeks ago it wasn't _on_ the
>> list. Now it's like the last 'copter outta Saigon.
>
> That's not true. SIMD intrinsics has always been on the list. I've only
> been in this newsgroup for a year or so, but I've definitely seen D's
> lack of SIMD support mentioned in several discussions so far. It's a
> frequent complaint about the language.

I made a cursory search and the last thread before nowadays is 
"Vectorizations intrinsics for DMD?" started on 2/6/11 by... Peter 
Alexander.

>> 2. We haven't identified game designers as a core market, and one that's
>> more important than e.g. general purpose programmers who need the like
>> of working qualifiers, multithreading, and shared libraries.
>
> Game programming is quite clearly a very large market for D.

We've never identified it as such. My perception is that adoption of D 
is much larger in other industries (while still small in absolute numbers).

> The game
> industry is perhaps one of the largest software industries that still
> relies on having C/C++ level of efficiency and low-level access. It's
> also an industry that is absolutely sick of having to use C++. D is
> quite close to the perfect language for game developers.
>
> I think it's also telling that perhaps the most prolific (ex-)D coder,
> Tomasz, was a game programmer, and that one of the largest D libraries
> is Derelict, which is also aimed at games.
>
> Finally, if you look at the dsource projects,
> http://dsource.org/projects/ you'll see that Games make up quite a large
> chunk of what people are using D for.
>
> What do you think our core market is?

Walter and I think that our core market consists of general purpose 
programmers who don't want to compromise one of productivity and code 
efficiency in their work. This group includes programmers in other 
languages than C++.

>> 3. There was never a promise or even a mention that we'll deliver SIMD.
>> We virtually promise we deliver threads and expressive qualifiers, and
>> there's still work to do on that.
>
> Fair point.

Fair is not the half of it. As a speaker and ambassador of D, it is 
difficult for me to stay with the conservative examples, being unable to 
showcase the really strong differentiating features because they're 
insufficiently implemented.

>> 4. There was broad agreement that the main foci going forward would be
>> quality, expressive qualifiers, shared libraries, Phobos work, and
>> publicizing the language. We can't work with and publicize D's awesome
>> concurrency design if parts of it aren't implemented.
>
> I suspect that SIMD support will greatly help to publicize the language.

I don't. I have zero evidence to believe that claim. Not one reader or 
one attendee asked me about that. They ask me about things such as (a) 
compiler quality; (b) concurrency; (c) availability on non-Intel 
platforms; (d) libraries, including the frequent "algorithms are cool, 
but when will you have STL-like containers?" Thank God the question 
"what's the deal with D1/D2 and Phobos/Tango?" is not asked anymore. 
Announcing support cessation for D1 must have been the best decision we 
took in 2011.

>> 5. The SIMD work has _zero_ acceleration on existing code; it only
>> allows experts to write non-portable code that uses SIMD instructions.
>> Updating to the next release of dmd has zero SIMD-related benefit to
>> statistically our entire user base.
>
> Where are you getting the figures for the % of people that will benefit
> from SIMD support? The SIMD support thread is rather large, so that
> suggests to me that a significant number of people are quite interested
> in the SIMD work.

I think it's tempting but inaccurate to gather numbers from the thread. 
I predict SIMD support will come and stay, and it will make no impact on D.

>> Walter and I spend hours on the phone discussing strategies and tactics
>> to make D more successful. And then comes this binge. Doing anything on
>> SIMD now is a mistake that I am sorry I was unable to stop. About the
>> only thing that's good about it all is that it'll be over soon.
>
> I can't speak on your private conversations with Walter, but I think
> you're underestimating how important SIMD support is for D.

I understand. I think you're overestimating it. The future will tell.

> Also, it appears (from his rate of progress) that Walter is quite
> enjoying the SIMD work. I see no harm in a short-lived "binge" if it
> reinvigorates Walter's interest in compiler work -- especially if you
> please a large part of the community in the process.

Yes. Totally agree. The way I see it, it's a welcome vacation.


Andrei