Introduce a VM-only dart:scalarlist library for byte arrays.

Introduce a VM-only dart:scalarlist library for byte arrays.

Include it in the SDK so users can use it. Create a dummy
implementation and patch file for the library for dart2js so it can be
documented. Johnni, can you think of a nicer way of making
documentation generation work for a VM only library? Also, it seems that
patching kills the documentation comments and they do not show up in
the generated docs.

R=iposva@google.com,johnniwinther@google.com
BUG=

Committed: https://code.google.com/p/dart/source/detail?r=12616

[Mads Ager (google), 2012-09-14 10:48:21]

Sorry about that. I forgot to add three files to the changelist. It is all there
now. Johnni, the files that I had to add for dart2js to see the library for doc
generation are in the lib/compiler/implementation/lib directory.

[Johnni Winther, 2012-09-14 11:45:10]

LGTM for the dart2js part

[dgrove, 2012-09-18 22:08:17]

Mads - can this be part of dart:core? I would really prefer that over adding
another small library.

[cshapiro, 2012-09-18 23:30:33]

Hi Mads,

If this is not part of dart:core, how is Dartium supposed to make use of
ByteArrays for its access to typed arrays?

Why does this have to be a new library and not just part of dart:core with a
small patch file for dart2js?

Carl

[Mads Ager (google), 2012-09-19 05:57:09]

On 2012/09/18 22:08:17, dgrove wrote:
> Mads - can this be part of dart:core? I would really prefer that over adding
> another small library.

No, this is not part of core. There is no notion of float32, int32, uint8 and so
on in Dart. This is a library thing in the same way we have the library for
fixed sized ints. We had discussions about this in AAR. This is the first step
to move them out of limbo. This library will be a good place to put
vector/matrix math as well.

[Mads Ager (google), 2012-09-19 06:00:42]

On 2012/09/18 23:30:33, cshapiro wrote:
> Hi Mads,
> 
> If this is not part of dart:core, how is Dartium supposed to make use of
> ByteArrays for its access to typed arrays?

Easy, it imports dart:scalarlists in dart:html. All the bindings will have to
get updated to take these types as well as the dart:html Uint8Arrays and
friends. That work needs to be done anyway, so I don't see how this makes
anything more complicated on that front. :)

> Why does this have to be a new library and not just part of dart:core with a
> small patch file for dart2js?

There is no nothing of these types in javascript. This library could be
implemented for dart2js by using the Uint8Arrays and friends from dart:html when
that is available. I don't see a good reason for making this part of core. The
only argument I have heard is one for convenience when integrating with dartium.
I don't think it is true that it would be easier if this was in core. There is
work to be done in the bindings and that has to be done no matter which library
have these types.

[dgrove, 2012-09-19 06:03:09]

On 2012/09/19 06:00:42, Mads Ager wrote:
> On 2012/09/18 23:30:33, cshapiro wrote:
> > Hi Mads,
> > 
> > If this is not part of dart:core, how is Dartium supposed to make use of
> > ByteArrays for its access to typed arrays?
> 
> Easy, it imports dart:scalarlists in dart:html. All the bindings will have to
> get updated to take these types as well as the dart:html Uint8Arrays and
> friends. That work needs to be done anyway, so I don't see how this makes
> anything more complicated on that front. :)
> 
> > Why does this have to be a new library and not just part of dart:core with a
> > small patch file for dart2js?
> 
> There is no nothing of these types in javascript. This library could be
> implemented for dart2js by using the Uint8Arrays and friends from dart:html
when
> that is available. I don't see a good reason for making this part of core. The
> only argument I have heard is one for convenience when integrating with
dartium.
> I don't think it is true that it would be easier if this was in core. There is
> work to be done in the bindings and that has to be done no matter which
library
> have these types.

Can we please have a broader discussion about this? AFAIK, this is coming out of
the blue to anyone who wasn't in Aarhus last week.

[kasperl, 2012-09-19 10:00:54]

I haven't looked at the details of this change, but I'm *very* supportive of not
having these VM specific classes injected into our core library.

Seen from the dart2js side, it makes little sense to have classes in the core
library that can only be efficiently implemented through interfacing to native
DOM classes. I strongly prefer to keep that support in the dart:html library,
but I wouldn't have a problem supporting dart:scalarlist on dart2js by
re-exporting those classes from dart:html (to cut down on the namespace
pollution you get when you want to use the "typed array" classes).

[cshapiro, 2012-09-19 23:30:17]

Hi Kasper,

Regarding your comment, the {Int,Uint}{8,16,32,64}List and Float{32,64}List
types are efficiently implementable with ordinary List<int> and List<double>
instances.  Access to the DOM types is not required.

Thanks,

Carl

[Ivan Posva, 2012-09-20 06:42:26]

One comment on top of the ones we had in direct discussion.

-Ivan

https://codereview.chromium.org/10919267/diff/2002/runtime/vm/object.cc
File runtime/vm/object.cc (right):

https://codereview.chromium.org/10919267/diff/2002/runtime/vm/object.cc#newco...
runtime/vm/object.cc:557: Library::InitScalarlistLibrary(isolate);
Can you explain why this has to be done so early?

[Mads Ager (google), 2012-09-20 06:49:43]

Fix intrinsifier. Thanks Ivan.

https://codereview.chromium.org/10919267/diff/2002/runtime/vm/object.cc
File runtime/vm/object.cc (right):

https://codereview.chromium.org/10919267/diff/2002/runtime/vm/object.cc#newco...
runtime/vm/object.cc:557: Library::InitScalarlistLibrary(isolate);
On 2012/09/20 06:42:26, Ivan Posva wrote:
> Can you explain why this has to be done so early?

The code below adds the classes to the library, so we need the library here for
the same reason as we need it for core and coreimpl since classes are added
explicitly below.

[Ivan Posva, 2012-09-20 07:07:02]

LGTM -ip