Re: [eclipse-incubator-e4-dev] SWT thread in managed runtimes

[Steve Northover <Steve_Northover@xxxxxxxxxx>]

Thanks for the info.

Fabian Jakobs <fabian.jakobs@xxxxxxxx>
Sent by: eclipse-incubator-e4-dev-bounces@xxxxxxxxxxx

04/08/2008 05:25 PM

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Subject	Re: [eclipse-incubator-e4-dev] SWT thread in managed runtimes

Mike Wilson schrieb:
>> Since there are no threads on the web...
>>     
> If that's true, what does this mean:
>    "...the founders of Ajaxian.com discuss the latest
developments,
>    including multithreaded _javascript_ technology-powered
UIs..."
>   
Hard to tell by just reading the talk description. There is currently 
only one technology, which allows real multi-threading in AJAX 
applications: the Google Gears worker pools 
<http://code.google.com/apis/gears/api_workerpool.html>. But these
worker pools are quite limited (e.g. no access to the DOM) and only work
with the gears plugin installed.

There are some pure _javascript_ approaches, which try to provide at least
cooperative multi threading but they all require preprocessing.

Interesting projects in this area are:

 - Narrative _javascript_ by Neil Mix 
<http://www.neilmix.com/narrativejs/doc/>: Adds blocking capabilities
to 
remove all the callbacks from the control flow. Add custom language 
extensions and compiles it to plain _javascript_
 - Strands by Kris Zyp <http://www.xucia.com/strands-doc/index.html>:
Uses the "yield" operator present in FireFox 2 to achieve cooperative
multithreading and "pseudo"-blocking for asynchronous events.
Strands 
can transform the code containing the yield statement into _javascript_ 
code without yield statements.

There are some more projects I don't remember right now.

The basic problem these projects want to solve is that once you are 
asynchonous e.g. by calling the server, you have to stay asyncronous in
the whole call stack. There is no way of synchronization or blocking for
an event. You really have to be careful to not clutter the API with all
those callback parameters, otherwise the control flow of the application
will be very hard to understand and debug.

I guess this will be a hot topic in bringing SWT to the browser.


Best Fabian

-- 
Fabian Jakobs
_javascript_ Framework Developer

1&1 Internet AG
Brauerstraße 48
76135 Karlsruhe

Amtsgericht Montabaur HRB 6484

Vorstand: Henning Ahlert, Ralph Dommermuth, Matthias Ehrlich, Andreas Gauger,
Thomas Gottschlich, Matthias Greve, Robert Hoffmann, Markus Huhn, Achim
Weiss
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