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digitalmars.D.learn - Can we ease WASM in D ?

reply bioinfornatics <bioinfornatics fedoraproject.org> writes:
Dear community,

I look some day ago to the D wasm page:
-> https://wiki.dlang.org/Generating_WebAssembly_with_LDC

And since then I ask myself can we at  compile time convert a D 
code to an extern C code for wasm ?

Indeed, if a library/framework  would wrap this to let end user 
write his code in plain D that would be awesome.

So did you think it is possible to do it by using 
metaprogramming, mixin, mixin template, mixin string … ?

Thanks for your ideas
Nov 16 2022
next sibling parent reply Adam D Ruppe <destructionator gmail.com> writes:
On Wednesday, 16 November 2022 at 22:51:31 UTC, bioinfornatics 
wrote:

 And since then I ask myself can we at  compile time convert a D 
 code to an extern C code for wasm ?


It would be pretty cool if you could just mark ` wasm` on a 
function and have it magically convert... the dcompute thing i 
*think* does something like this. but im not sure.


 Indeed, if a library/framework  would wrap this to let end user 
 write his code in plain D that would be awesome.

 So did you think it is possible to do it by using 
 metaprogramming, mixin, mixin template, mixin string … ?


What I've done before (including the webassembly.arsdnet.net 
website) is have the server call the compiler as-needed when 
requesting the file, which makes it feel pretty transparent. You 
might want to do that too, it'd be on the file level instead of 
on the function level but it works.
Nov 16 2022
parent max haughton <maxhaton gmail.com> writes:
On Wednesday, 16 November 2022 at 23:00:40 UTC, Adam D Ruppe 
wrote:

 On Wednesday, 16 November 2022 at 22:51:31 UTC, bioinfornatics 
 wrote:

 [...]


 It would be pretty cool if you could just mark ` wasm` on a 
 function and have it magically convert... the dcompute thing i 
 *think* does something like this. but im not sure.


 [...]


 What I've done before (including the webassembly.arsdnet.net 
 website) is have the server call the compiler as-needed when 
 requesting the file, which makes it feel pretty transparent. 
 You might want to do that too, it'd be on the file level 
 instead of on the function level but it works.


This is what it does, albeit with a pretty wacky pipeline because 
GPUs be crazy.
Nov 16 2022
prev sibling next sibling parent reply "H. S. Teoh" <hsteoh qfbox.info> writes:
On Wed, Nov 16, 2022 at 10:51:31PM +0000, bioinfornatics via
Digitalmars-d-learn wrote:

 Dear community,
 
 I look some day ago to the D wasm page:
 -> https://wiki.dlang.org/Generating_WebAssembly_with_LDC
 
 And since then I ask myself can we at  compile time convert a D code
 to an extern C code for wasm ?
 
 Indeed, if a library/framework  would wrap this to let end user write
 his code in plain D that would be awesome.


You mean with Phobos and everything included?  I think there may be
issues with that... because the current WASM does not define a memory
management mechanism, so you'd have to convert the GC implementation to
work with WASM.  Which would have issues with deployment because AIUI
currently WASM still requires Javascript to initiate running it; if
druntime needs special handling, for example, then you'd have to worry
about coordinating with any JS code that the user may also wish to
deploy, for example.  There are also language constructs that may not be
supportable, like exceptions that propagate beyond the JS/WASM boundary
(although if we add a layer of indirection to D functions called from
JS, this might be possible to shoehorn into a semblance of working).

I did actually play with this a week or two ago; and found that it was
actually quite difficult to get meaningful native code (D or otherwise)
off the ground, because of the currrently mandatory Javascript component
that need not only to load and initialize the WASM module, but also to
interface with various browser APIs --- since WASM cannot call any of
them directly, but has to go through a JS export/import API. String
support also needs a lot of boilerplate.

Which actually gave me the idea of a D-based framework that uses
compile-time introspection, etc., to auto-generate the necessary JS glue
code (e.g., as a pre-compile step[1]) so that the user does not actually
have to write any JS manually for things to work.

[1] I.e., there'd be a special D helper tool that imports your user D
code and performs introspection on it, and spits out JS glue code at
runtime. So you'd run this as part of your build, and it creates the
necessary JS file(s) that you need to insert into your HTML; in the
meantime, you run a separate build command to compile the user D code
into WASM.  (This is why dub seriously needs to break out of its single
executable modus operandi -- I don't think this can be easily bundled
with dub right now.)

Having this tool is essential to making D's WASM experience tolerable;
currently the insane amounts of JS boilerplate you have to write in
order to get non-trivial D code off the ground is ridiculous.  Trying to
write a WASM function that does string processing, for example, requires
a ton of hacks to work around the lack of a built-in string type.  D
could totally automate this crap away by having a wrapper tool that
introspects your D code at compile-time and spits out the necessary JS
boilerplate and any other needed shims in order to get this to work with
a minimum of fuss.  Also, interfacing with browser APIs like WebGL also
needs to be doable with a minimum of fuss, which currently isn't
possible because of the unavoidable JS component with its associated
boilerplate.


T

-- 
Hey, anyone can ignore me and go ahead and do it that way. I wish you the best
of luck -- sometimes us old coots are dead wrong -- but forgive me if I'm not
going to be terribly sympathetic if you ignore my advice and things go badly!
-- Walter Bright
Nov 16 2022
parent reply Adam D Ruppe <destructionator gmail.com> writes:
On Wednesday, 16 November 2022 at 23:16:26 UTC, H. S. Teoh wrote:

 You mean with Phobos and everything included?  I think there 
 may be issues with that...


Yes, this is a problem, but I think I have a solution: defer GC 
runs until javascript is running. There's also some llvm features 
that might fix it.

If I had a spare day I think I could play with it.



 Which actually gave me the idea of a D-based framework that 
 uses compile-time introspection, etc., to auto-generate the 
 necessary JS glue code (e.g., as a pre-compile step[1]) so that 
 the user does not actually have to write any JS manually for 
 things to work.


Sebastiaan Koppe generates the D/JS glue code from web standards. 
I've done it more dynamically inside D itself (exposing an `eval` 
hook on the JS side).

Sebastiaans: https://github.com/skoppe/spasm

mine: 
http://dpldocs.info/this-week-in-d/Blog.Posted_2020_08_10.html

Actually pretty easy to solve.
Nov 16 2022
parent bioinfornatics <bioinfornatics fedoraproject.org> writes:
Thanks Adam, H. S., max for your point of view

On Wednesday, 16 November 2022 at 23:23:48 UTC, Adam D Ruppe 
wrote:

 On Wednesday, 16 November 2022 at 23:16:26 UTC, H. S. Teoh 
 wrote:

 You mean with Phobos and everything included?  I think there 
 may be issues with that...





Yes that would be really fantastic to get those enhancement. As 
example I see this wasm framework wrote in rust: 
https://github.com/yewstack/yew

Get a such framework in D wold be helpful
Nov 16 2022
prev sibling next sibling parent Jesse Phillips <Jesse.K.Phillips+D gmail.com> writes:
On Wednesday, 16 November 2022 at 22:51:31 UTC, bioinfornatics 
wrote:

 Dear community,

 I look some day ago to the D wasm page:
 -> https://wiki.dlang.org/Generating_WebAssembly_with_LDC

 And since then I ask myself can we at  compile time convert a D 
 code to an extern C code for wasm ?


 Thanks for your ideas




Not exactly related, but this effort seemed to have gotten pretty 
far. But is old now https://code.dlang.org/packages/spasm
Nov 23 2022
prev sibling parent Hipreme <msnmancini hotmail.com> writes:
On Wednesday, 16 November 2022 at 22:51:31 UTC, bioinfornatics 
wrote:

 Dear community,

 I look some day ago to the D wasm page:
 -> https://wiki.dlang.org/Generating_WebAssembly_with_LDC

 And since then I ask myself can we at  compile time convert a D 
 code to an extern C code for wasm ?

 Indeed, if a library/framework  would wrap this to let end user 
 write his code in plain D that would be awesome.

 So did you think it is possible to do it by using 
 metaprogramming, mixin, mixin template, mixin string … ?

 Thanks for your ideas



It should not be too hard to do that using mixin templates. The 
concept is the same from my ` ExportD` that I'm using on my 
engine.

What ` ExportD` does is to create a new function based on the 
function target function  [or even classes] which all it does is 
call that (or even attach a GC.root as needed ), and generates 
factory functions for classes or create some `extern(C) export` 
the function.

I have done the same thing also for Lua and Java, don't seem that 
hard to do it with WASM. The only difference is that you will 
need to mixin template yourself (I do it at the end of file), 
then I iterate through the module members containing your ` wasm` 
UDAs, and generate the functions needed.

Remember that you could also use things such as 
` wasm("myNewFunctionName")` and handle such cases.

But for me, working with D without a D runtime is simply not 
worth. That being said, if we had a working D runtime for WASM I 
would be adapting my engine to support it too.
Nov 23 2022