[Pyobjc-dev] exception handling design pattern

[Bill B. <bb...@co...>]

If I implement something like...

   def foo(self):
     try:
       serverAPIVersion = int( versionInfo['currentXmlRpcVersion'] )
       serverAppVersion = int( versionInfo['applicationVersion'] )
     except KeyError, aKey:
       NSException.raise_format_(NSInternalInconsistencyException, " ** 
%s key not found in getVersionInfo() response>" % aKey)

... and am calling this code from ObjC (i.e. objc->python->objc 
exception), I would expect that the raised NSException would be 
transparently passed back through to ObjC.  That is:

NS_DURING
     [instanceOfPythonObject foo];
NS_HANDLER
     ... handle the raised NSException here ...
NS_ENDHANDLER

This would seem to be consistent with the ObjC implementation pattern.  
That is, it wouldn't matter if -foo is implemented in Python or in the 
ObjC parent class of the python class, the behavior would be consistent.

Looking at the implementation, it looks like the problem lies in the 
behavior of the ObjC->Python part of the bridge in that it leaves the 
NSException in a wrapped up state?

I'm not sure how this would influence the relatively complex situation 
of, say, ObjC->Python->ObjC->Python->Objc exception raised... I.e. in 
the 'ObjC' parts of the stack, you want to raise the exception and let 
the next level up's interface between Python->ObjC catch it, convert it 
into the appropriate Python exception, then convert it back into an 
NSException at the next ObjC->Python extension (keeping in mind that 
the exception goes from right to left).

b.bum