invokedynamic: Is It What We Really Need?

[Alex Tkachman]

Here are my thoughts on invokedynamic proposal.

http://groovyland.wordpress.com/2008/05/09/invokedynamic-is-it-what-we-really-need/

Alex

[John Wilson]

On 5/9/08, Alex Tkachman <alex.t...@gmail.com> wrote:
>
> Here are my thoughts on invokedynamic proposal.
>
> http://groovyland.wordpress.com/2008/05/09/invokedynamic-is-it-what-we-really-need/

I think it's unfortunate that the JSR was started with a solution
(invokedynamic) rather than a problem (implementing dynalangs on the
JVM is hard). This is not reflection on John who came to the JSR long
after it was created.

I have a lot of sympathy for the position that you outline in your
blog post but I would like to wait for the EDR to be published before
coming to a settled view on the matter. The devil is in the details
and I have not seem all the details yet.

John Wilson

[Alex Tkachman]

>
> I have a lot of sympathy for the position that you outline in your
> blog post but I would like to wait for the EDR to be published before
> coming to a settled view on the matter. The devil is in the details
> and I have not seem all the details yet.
>

I am totally agree. At the end of the day what I say is that API
understanded by JVM is better then a new bytecode because it is
backword compatible :)

[Charles Oliver Nutter]

Current EDR does not introduce a new bytecode, and prefers to have a
"special" interface for invokeinterface as a marker for dynamic
invocation. The EDR should be public next week.

And although this particular part of the approach would not be
back-portable, I'm planning to work with you and John Rose and others to
create a backport of the anonymous classloading and method handle APIs.
John Rose has also spoken frequently about the importance of solving
these issues on older JVMs as well.

- Charlie

[John Rose]

Wanting to capture some memories from JavaOne before they fade, and
hoping to provide some perspective on where the JVM and its languages
might be going, I have written out some impressions on these things.
Enjoy:

http://blogs.sun.com/jrose/entry/the_golden_spike

It will be great to discuss the EDR on this list when it comes out
from the JCP. I am hoping this will be the primary public venue for
such conversations.

One caveat: The EDR is an early draft, and lacks javadocs. The Java
APIs are merely sketched.

I will start committing code to the mlvm repo. in coming weeks, and
then we can make javadocs and talk about the detailed shape of the APIs.

-- John

[Patrick Wright]

> I think it's unfortunate that the JSR was started with a solution
> (invokedynamic) rather than a problem (implementing dynalangs on the
> JVM is hard). This is not reflection on John who came to the JSR long
> after it was created.

See Gilad's old blog entry at
http://blogs.sun.com/gbracha/entry/invokedynamic and other blogs from
around that time. "Last winter we had a meeting with various people
who work on such languages - things like Groovy, Perl, Python/Jython.
Our conclusion was that the most practicable thing was to support
dynamically typed method invocation at the byte code level." There are
some other notes about that meeting floating around on the web
somewhere that were published at the time. If this list had existed
then, we'd have more information about what was discussed back then
and why they came up with the invokedynamic idea.

Regards
Patrick

[Guillaume Laforge]

I'd add the our knowledge of implementing dynamic language on the JVM
has evolved a lot since 3 years ago.
The reasons back then may differ with the knowledge we have now.

--
Guillaume Laforge
Groovy Project Manager
G2One, Inc. Vice-President Technology
http://www.g2one.com

[John Wilson]

Yes I remember the meeting very well (I wasn't at the meeting but I
was already working on Groovy when it happened). At the time we
expected it to be the beginning of an engagement with Sun on the
problems of getting dynamic languages to run efficiently on the JVM.
The invokedynamic proposal came as something of a surprise to us it
was, and remains, difficult to see how we might have made use of it.
Bracha was not very forthcoming with details and moved on to other
things before he was able to enter into a dialogue.

This mailing list has made a huge difference and it's been very
valuable to be able to exchange information with others who share the
problem. Charlie has done a great job here.

I understand from postings on this and the Groovy list that the
current proposal does not include a new bytecode so perhaps my
original opinion of the utility of invokedynamic was not completely
wrong.

We must, of course, wait for the publication of the proposal before
coming to an informed position this.

John Wilson

[John Wilson]

On 5/13/08, Patrick Wright <pdou...@gmail.com> wrote:
>

Tim Bray set the meeting up and this is his report on it
http://www.tbray.org/ongoing/When/200x/2004/12/08/DynamicJava

John Wilson