Re: Time to branch off 4.0 from 4.1?

[Ethan M. <merritt@u.washington.edu>]

On Friday 18 June 2004 06:09 am, you wrote:
>
> If user closes gnuplot_x11, 

If a user kills gnuplot_x11 then all bets are off.  Killing it (SIGTERM etc)
will bypass any code that I add.  So I assume you mean:
if a user closes the plot window...

> then "show variables" should have define all 
> usual mousing variables, obviously with zero values, and the MOUSE_KEY
> should be set to -1:

I do not like this idea at all.
zero is a legal coordinate value, so setting coordinates to zero is not a safe way
of indicating an abnormal return.

> This is absolutely important in order not to break scripts for
> bidirectional communication of other programs with gnuplo, which get
> feedback from mousing by writing the above MOUSE_* values to pipe /
> fifo.

But a script should not assume that any of these variables are defined. 
In fact they are not defined to begin with, and only become defined
at the time a mouse click is first requested and successfully recognized.
I suggest that the proper fix is to modify your scripts to test for the
existence of the variable before trying to print it.

This is simply a specific example of the more general case of 
user-defined variables.  Scripts are free to define and use variables
via gnuplot, but they cannot assume the variables are defined. Or else
they must be very careful to insure that a variable becomes defined
before trying to use it, but that strikes me as a dangerous programming
style.

> Finally, what do you think about this: "q" hotkey is disabled when
> "pause mouse key" comes to action;

I have been unable to figure out how to do this.
The "q" hotkey is handled directly by gnuplot_x11, which doesn't know
anything about "pause mouse".   I think it would take a separate
communication channel and a new set of driver calls to implement 
this, since gnuplot would have to inform gnuplot_x11 asynchronously
that it is requested to change how it is handling X11 input events.
Frankly, I think it would be a huge headache to get this working.

The only alternative I have been able to come up with is to
move the "q" processing for the current plot window out of gnuplot_x11
altogether, and make it equivalent to 
   bind 'q' '<some command related to set term x11 close>'
If you have any better ideas, please speak up.

> thus, command.c should call 
> "x11_hotkeys(0)" and afterwards "x11_hotkeys(1)" to enable them again.

x11_hotkeys()?   Is this a new driver primitive that you have designed?
I agree it would be possible to do this sort of thing by adding a new set
of driver primitives.  But that's a big job and I don't have time to tackle it.

-- 
Ethan A Merritt       merritt@u.washington.edu
Biomolecular Structure Center
Mailstop 357742
University of Washington, Seattle, WA 98195