[Openmcl-devel] Debugging Cocoa (was: programmatic file chooser? thanks!)

[Rainer Joswig]

Am 28.08.2008 um 21:34 schrieb Alexander Repenning:

> Thanks Gary for the detailed response. I have just spent some time  
> to write some basic GUI code based on Cocoa in LispWorks and Clozure  
> CL. I could go on about the philosophical differences between LW and  
> CCL wrt Cocoa but that is perhaps left best for some other time. At  
> the end of the day both approaches work.
>
> CCL gets high scores for having defined interfaces, based on reading  
> the header files I presume. LW includes no such information. As  
> developer I have to define my own function/method/constant  
> definitions for Cocoa and other APIs in LW. Not very practical for  
> large APIs.
>
> The main problem, we found with CCL and Cocoa, especially vis-a-vis  
> LW, is debugging. Specifically, CCL makes it hard to debug Cocoa  
> call backs. Example: Say I have a window (NSWindow containing  
> NSView) with a buggy event handler.
>
> (defmethod VIEW-LEFT-MOUSE-DOWN-EVENT-HANDLER ((Self event-test- 
> Window) X Y)
>   (format t "click: x=~A, y=~A~%"  x y)
>   (setf (x self) x)
>   (setf (y self) y)
>   (/ x 0) ;; division-by-zero!!!
>   (print *Current-process*)
>   (view-draw-contents Self))
>
> 1) output to OS X console does not work as interactive debugging  
> tool. There is too much lag. The print/format statements, if you  
> start CCL 1.2 by double clicking the OS X app will produce output in  
> the OS X console with great lag time.


Probably not related to this, but I'll mention it anyway, since I have  
seen this in other debugging contexts:
Sometimes the output streams are buffered (and the display gets  
updated sometime later) and one needs to
call FINISH-OUTPUT or FORCE-OUTPUT after printing something to see any  
debug information immediately.
Please ignore above if it does not apply here...

...

Rainer Joswig, Hamburg, Germany
http://lispm.dyndns.org/
mailto:joswig at lisp.de