Re: [matplotlib-devel] propagation of error messages in matplotlib

[Steve C. <ste...@ya...>]

I've updated backend_gtk.py in cvs to use a default exception handler,
and noticed a few things in the process:
 - sys.excepthook does not catch SystemExit, which is what we wanted
anyway.

 - for some errors I needed to display a matplotlib message rather than
the default exception message, or to raise an exception where error_msg
() was used with no exception. I added an 'MPLError' exception, its
probably best to move it into a central file if other people need to use
it also.

 - changing from error_msg() to raise exception means the rest of the
method will not execute, which I hadn't thought about. This is no good
for 'get_filename_from_user()' where I want to loop until a file (or
Cancel) is selected. So I think GTK still has a need to use of a popup
message dialog occasionally.
And for print_figure() it means the section of code to restore figure
settings will not get executed after an error.

Steve