Tcl and Scilab Event loop

[Bruno JOFRET]

Hi all puffin friends !

First of all, I wish all of you my best wishes for 2008 : health and 
happiness !
And obviously a great success for Scilab 5 and beyond.

I'm now working on the Tcl running in Scilab and the "Scilab Event Loop".
I confess with the new Java GUI, TCL based stuff were muddy.

Some answers on that issue :
- Tcl based GUI needs manually "update" in order to live.
Of course because Tcl is a scripting language.
-  Scilab was strongly single threaded and running in an endless loop
(that's why it was able to update Tcl/Tk periodically)

Now with the Java gui the "update" loop was slowed down (not so often 
called).
This explain why it looks so muddy.

The main idea of my work was to unlink scilab internal behaviour and Tcl 
management.

For that issue I created the TCL Interpreter used in Scilab in it's 
single thread.
It works as follow :
* I created a timer thread within this one
* WHILE Tcl is started
    IF we have a TCL command to execute
       runIt
    ELSE
       Do "update"
       Wait until we receive a "wake up" signal
    ENDIF
ENDWHILE

The timer thread is quite dummy.
It only send  periodically a "wake up" signal.

"Wake up" signal are also send when asking for a TCL command through Scilab.
A call to Tcl_EvalStr for instance.

It works pretty well on my computer but has some restrictions.
- I used pthread that is not supported on Windows.
But we are working to native similar thread management on Windows.
- Some others commands may be broken.

Some improvements are quite cool :
- You can now run some huge stuff in Scilab, and continue to write in 
Scipad.
- No more muddy help browser.
- Whole Scilab behaviour is decreasing computation power need.

Keeping in mind I absolutely do not want to break any OS Scilab version,
neither any Scilab Tool (Scipad, ged, ...) ,
- What do you think of that "algorithm" and did you see any hidden 
drawbacks within it ?
- As soon as we will have Windows similar functionalities, and taking 
into account your comments,
we will include this into the Trunk and kindly ask you for some feedbacks.


Regards,

-- 
Bruno JOFRET

         Project Engineer
___SCILAB - INRIA Rocquencourt___
  Domaine de Voluceau - B.P. 105
    78153 Le Chesnay Cedex
  Tel : (+33/0)1.39.63.58.63
  Mailto : bruno.jofret at inria.fr
     http://www.scilab.org