[Python-Dev] Pre-PEP: Exception Reorganization for Python 3.0

[Nick Coghlan]

Brett Cannon wrote:
>>Notice that I've classified KeyboardInterrupt as user-initiated control flow
>>and put it under ControlFlowException above. This means that everything under
>>CriticalError and Error actually ends with the word 'Error'.
> 
> I don't know if I like this change in inheritance.  While we do tend
> to use KeyboardInterrupt as a way to kill a program, is that really
> control flow, or a critical exception that the program needs to stop
> because an serious event occurred?
> 
> I prefer the latter explanation.

You're probably right. How does the following reasoning sound:

SystemExit, GeneratorExit and StopIteration are all deliberately triggered by 
certain well-defined elements of normal application code. That is, only 
certain operations will ever result in a ControlFlowException being raised.

KeyboardInterrupt is a better fit with MemoryError and SystemError - something 
that occurs unexpectedly, at an arbitary point during program execution. That 
is, a CriticalError may be raised when attempting to execute almost any operation.

Regards,
Nick.

-- 
Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia
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