Hi all,

I'd like to make a WASM project, and looking into options.

I can see that LDC supports WASM output, and I believe this requires BetterC to be enabled? The documentation states that classes are not supported by BetterC, but its preferable/required for me.

I have done some tests, and it appears that classes are supported (LDC 1.22.0)? Is it possible to get an update on what is and still isn't supported in BetterC?

After a stable experience, so if you can also let me know if these features are beta etc too?

Kind regards,
Mike

On Wednesday, 19 August 2020 at 21:24:23 UTC, Mike Brown wrote:
> I can see that LDC supports WASM output, and I believe this requires BetterC to be enabled?

Not really but anything beyond -betterC is still kinda diy right now.

So I happened to do port my little tetris game in D to wasm just last week, you can read about it here:
http://dpldocs.info/this-week-in-d/Blog.Posted_2020_08_10.html

And it uses classes! But... I cheated. I did a minimal custom druntime and library port that has just enough to make that little game work. This is a viable approach and can lead to reasonably small compiled binaries, but it is kinda immature.

For a full druntime, the author of spasm <https://github.com/skoppe/spasm/> is working on a port. See his fork here:

https://github.com/skoppe/druntime/tree/wasm

I say "full" but it will most likely leave some things out. Classes, GC (at least of D memory), and other features all should work already if you brave building it yourself, but threads do not work and exceptions are only partially supported. Read more here: https://gist.github.com/skoppe/7617ceba6afd67b2e20c6be4f922725d

That may change in the future as wasm gets more standardized capabilities.

Other libraries, including interop with javascript, are not covered by the druntime goal, but they will probably get easier with this.

> I have done some tests, and it appears that classes are supported (LDC 1.22.0)? Is it possible to get an update on what is and still isn't supported in BetterC?

How did you compile it? You can definitely make classes work but as far as I knew it didn't "just work" but maybe that changed with the recent release.

> After a stable experience, so if you can also let me know if these features are beta etc too?

but yeah stability is probably a ways out still. Sebastiaan has been busy lately so his druntime work is on pause and mine was just one weekend so I'd have something to show off on the blog; I have no concrete plans of continuing right now.

Good chance we'll get it all working eventually, but I wouldn't expect even beta stability - aside from the diy betterC stuff - any time soon. Maybe beta quality by the end of the year. Maybe.

On Wednesday, 19 August 2020 at 21:24:23 UTC, Mike Brown wrote:
> Hi all,
>
> I'd like to make a WASM project, and looking into options.

It's scattered in several places including
https://gist.github.com/skoppe/7617ceba6afd67b2e20c6be4f922725d

Are you aware of Spasm?
https://github.com/skoppe/spasm

On Wednesday, 19 August 2020 at 21:24:23 UTC, Mike Brown wrote:
> I have done some tests, and it appears that classes are supported (LDC 1.22.0)?

extern(C++) classes are supported by -betterC. With LDC, D classes are supported to some extent too since v1.11, but this requires a custom object.d (custom Object base class).

Hi All,

Thank you for your replies. My tests have been via compiler explorer.

https://godbolt.org/z/4f9nKj I have done this without -BetterC, as the dynamic array fails. I guess that uses GC? Is there an alternative that works with BetterC for dynamic arrays?

Thank you for the other WASM links, I initially only need to call a single function, compute, and return a string. But the idea of the dlang side interacting with the JS side sounds useful and promising.

Is the use of classes in my example a special case? And more expanded usage will break?

Kind regards,
Mike Brown

On Tuesday, 1 September 2020 at 20:39:58 UTC, Mike Brown wrote:
> Hi All,
>
> Thank you for your replies. My tests have been via compiler explorer.
>
> https://godbolt.org/z/4f9nKj I have done this without -BetterC, as the dynamic array fails. I guess that uses GC? Is there an alternative that works with BetterC for dynamic arrays?

You could try http://mir-algorithm.libmir.org/mir_rc_array.html or the planned core.experimental.rcarray (https://github.com/dlang/druntime/pull/2679).

Hi again,

I now understand the issues at play. I get linking errors to the druntime features. I now understand the earlier replies.

I was able to resolve all but TypeInfo errors from the suggested druntime replacements. Coming from a C++ background - I’m not even sure how I’m using TypeInfo features so I don’t even know where to begin on rewriting my code to not use it. Also not sure how I’d go able altering the druntime to proceed. Happy to leave wasm with D at that.

I did however, get taken in by how small and precise the D code was compared to my C++ equivalent. The templating is beautiful, I’m now considering writing in D rather than C++ as the smaller and clearer code would be of real benefit.

Thanks again to all replies. I read all linked articles, which were all great reads. Hope wasm support arrives officially one day soon.

Kind Regards
Mike Brown

On Thu, Sep 03, 2020 at 06:18:00PM +0000, Mike Brown via Digitalmars-d-learn wrote: [...]
> I did however, get taken in by how small and precise the D code was compared to my C++ equivalent. The templating is beautiful, I’m now considering writing in D rather than C++ as the smaller and clearer code would be of real benefit.
[...]

I also came from a C/C++ background, and D's conciseness, beautiful syntax, and general "hygiene" continue to impress me every day. I gave up C++ for D years ago, and have never looked back since.


T

-- 
Без труда не выловишь и рыбку из пруда.

On Tuesday, 1 September 2020 at 20:39:58 UTC, Mike Brown wrote:
> Is there an alternative that works with BetterC for dynamic arrays?

You may give these a try:
https://github.com/aferust/dvector

For associative arrays: https://github.com/aferust/bcaa