[Cython] [cython-users] C++: how to handle failures of 'new'?

[Stefan Behnel]

mark florisson, 05.07.2012 20:47:
> On 3 July 2012 20:15, Robert Bradshaw wrote:
>> On Tue, Jul 3, 2012 at 11:43 AM, Dag Sverre Seljebotn
>>> Though I guess one might want to try to pull out the try-catch to at least
>>> only one per code line rather than one per SimpleCallNode.
>>
>> Or even higher, if possible. It's still a lot.
> 
> Why would you have to do that? Can't you just insert a try/catch per
> try/except or try/finally block, or if absent, the function body. That
> will still work with the way temporaries are cleaned up. (It should
> also be implemented for parallel/prange sections).

My first reaction was, "sure, smart idea". It certainly sounds like a good
idea to unify the exception handling between C++ and Python into the same
syntactic structures.

But does it allow to handle different declarations for multiple C++
functions that get called? E.g. "except +" for one and "except
+MemoryError" for another, but both called in the same try-whatever block?
That would just lead to nested try-except blocks, I guess, thus making the
outer exception clauses mostly a fallback for exceptions that users forgot
to declare or couldn't properly handle for some reason.

I think it's worth a try to see if it works.

BTW, is there a reason we can't allow users to declare C++ exceptions in
their .pxd files, and then support catching them in Python try-except
syntax? Just verbatimly translating them to the C++ structures, based on
the type of the exception that gets caught?

(Although, given the discussion so far, maybe try-finally is more important
than try-catch, and the former can't know when it needs to be mapped into
C++ code and when not ...)

Stefan