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

[Fernando P. <Fer...@co...>]

John Hunter schrieb:
>>>>>>"Fernando" == Fernando Perez <Fer...@co...> writes:
> 
> 
>     >> Actually, it would be fine if matplotlib overrode
>     >> sys.except_hook and ipython later came along and overrode that.
>     >> Basically, ipython would be saying, "I know I've got a shell to
>     >> display errors in, so we don't need to GUI method".  I don't
>     >> think matplotlib would have a problem with that.  Ditto for
>     >> envisage.  Basically, we would be providing a default method to
>     >> get the message to the GUI which could be overriden by other
>     >> applications that want to (ipython, envisage, what-have-you).
> 
>     Fernando> I guess this is a good heads-up for me.  I know ipython
>     Fernando> does some of this, I'll just add a bit more such
>     Fernando> control.  That way, if during the running of user code
>     Fernando> they need sys.ehook for something, they'll get it.  But
>     Fernando> ipython will keep it for when it needs it.  I'm pretty
>     Fernando> sure the embeddable ipython has such control in it, I
>     Fernando> may just need to put it in the general case as well.
> 
>     Fernando> Ultimately I'm not 100% sure what a good solution for
>     Fernando> matplotlib is, I just wanted to make you aware of these
>     Fernando> issues, so that at least they are on your radar.
> 
> 
> We do have some more options.  For one, we could use the excepthook
> only in the matlab interface -- in this case matlab is being used more
> as an application rather than a library.  Folks using matplotlib as a
> library, eg embedding in a GUI, would be advised to do their own
> trapping.
> 
> The only exceptional case I see is basically the ipython (and friends)
> case.  Ie, someone wants to write a shell or otherwise that embeds
> matplotlib.matlab.  In this case it would be fine to override
> matplotlib.matlab's excepthook, as discussed.
> 
> To play really nicely, matplotlib.matlab would like to be able to
> override excepthook only if it hadn't been otherwise overridden.  I
> don't see any elegant way to do this.  Any ideas?

Yup:

planck[mayavi]> ip
In [1]: import sys

In [2]: sys.__excepthook__ is sys.excepthook
Out[2]: False

planck[mayavi]> python
 >>> import sys
 >>> sys.__excepthook__ is sys.excepthook
True

Cheers,

f