Implement export clause in VM

Implement export clause in VM

Implement export namespace support in VM compiler.

Missing functionality: ensuring that a name is only re-exported once.

[siva, 2012-10-08 20:17:42]

LGTM with couple of spec level questions:

1. The spec states that "A library may choose to re-export any of its imported
libraries" does this mean it is an error to have an 'export' statement in a
script. The current
implementation allows 'export' to be specified in a script too (nop though).
(Checked with Gilad and he says it is not an error).

2. what is the expected behaviour of:
export "xyz.dart" show A, B
export "xyz.dart" show C
I think currently A, B and C are visible, maybe that is correct.

http://codereview.chromium.org/11047027/diff/1/runtime/vm/object.cc
File runtime/vm/object.cc (right):

http://codereview.chromium.org/11047027/diff/1/runtime/vm/object.cc#newcode5387
runtime/vm/object.cc:5387: // Lookup a name in the library's export namespace.
maybe "library's exported namespace."

The name LookupExport also is a bit confusing as it seems to imply that we would
look for the name in the exports.

I would get rid of this function and just inline the
if (HasExports()) {
  ...
}

Stuff in Namespace::Lookup....

http://codereview.chromium.org/11047027/diff/1/runtime/vm/raw_object.h
File runtime/vm/raw_object.h (right):

http://codereview.chromium.org/11047027/diff/1/runtime/vm/raw_object.h#newcod...
runtime/vm/raw_object.h:678: RawArray* exports_;            // List of
re-exported Namespaces
missing '.'

[Ivan Posva, 2012-10-08 21:35:50]

http://codereview.chromium.org/11047027/diff/1/runtime/vm/object.cc
File runtime/vm/object.cc (right):

http://codereview.chromium.org/11047027/diff/1/runtime/vm/object.cc#newcode5387
runtime/vm/object.cc:5387: // Lookup a name in the library's export namespace.
On 2012/10/08 20:17:42, siva wrote:
> maybe "library's exported namespace."
> 
> The name LookupExport also is a bit confusing as it seems to imply that we
would
> look for the name in the exports.
> 
> I would get rid of this function and just inline the
> if (HasExports()) {
>   ...
> }
> 
> Stuff in Namespace::Lookup....

I will change it so that LookupExport will only lookup symbols in the exports,
and adapt the use further below.

[Ivan Posva, 2012-10-09 00:53:19]

Landed as https://codereview.chromium.org/11028084/

-Ivan

http://codereview.chromium.org/11047027/diff/1/runtime/vm/object.cc
File runtime/vm/object.cc (right):

http://codereview.chromium.org/11047027/diff/1/runtime/vm/object.cc#newcode5387
runtime/vm/object.cc:5387: // Lookup a name in the library's export namespace.
On 2012/10/08 21:35:50, Ivan Posva wrote:
> On 2012/10/08 20:17:42, siva wrote:
> > maybe "library's exported namespace."
> > 
> > The name LookupExport also is a bit confusing as it seems to imply that we
> would
> > look for the name in the exports.
> > 
> > I would get rid of this function and just inline the
> > if (HasExports()) {
> >   ...
> > }
> > 
> > Stuff in Namespace::Lookup....
> 
> I will change it so that LookupExport will only lookup symbols in the exports,
> and adapt the use further below.

Done.

http://codereview.chromium.org/11047027/diff/1/runtime/vm/raw_object.h
File runtime/vm/raw_object.h (right):

http://codereview.chromium.org/11047027/diff/1/runtime/vm/raw_object.h#newcod...
runtime/vm/raw_object.h:678: RawArray* exports_;            // List of
re-exported Namespaces
On 2012/10/08 20:17:42, siva wrote:
> missing '.'

Done.

[hausner, 2012-10-11 23:51:09]

Checked in by iposva as

http://codereview.chromium.org/11047027/