[Python-Dev] capturing RETURN_VALUE (original) (raw)

Tim Peters tim.peters at gmail.com
Mon Aug 9 01:32:00 CEST 2004

[Tim Peters]

It did in your specific example, but not necessarily. In your specific example, the finally block didn't execute "break" if an exception was raised, it only did "break" if the finally block was entered because of a return. If it had done "break" in the exception case too, it would have "abandoned" the exception too:

[Christian Tismer]

Sure, that was by design. I'm trying to inline functions into each other, with smallest possible changes to the bytecodes of the inlined functions. Exceptions shall pass through, returns shall be captured and not cause the embracing function to return, but to continue with the "returned" value.

The point was that exceptions and returns act the same way: RETURN_VALUE isn't unique here, it's just another instance of leaving a try-block's suite, the same in this respect as an exception or a break statement. That's why it's reliable over time: it's a general mechanism at work, not an arbitrary hack specific to RETURN_VALUE.

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