On 01/09/2025 14:26, marius.spix--- via Python-list wrote:
In your example when would isinstance(__exit_context__, ReturnContext)
be True and when would it be False? What would __exit_context__.value
be? I can't think of a sensible meaning for it. If no exception occurs,
is the value returned by f supposed to be 10/x or __exit_context__.value
+ 1 # whatever that is
Best wishes
Rob Cliffe
Dear Rob,
isinstance(__exit_context__, ReturnContext) would only be True, when the try,
except or else block is left using a return statement.
__exit_context__.value would be the return value of f(x), in that case 10/x.
Currently it is not possible to access this value in the finally block, but it
can be overwritten, as the return statement is compiled into a new RETURN_VALUE
opcode.
In this example, f(x) would return 10/x + 1 if x != 0 else 0.
I think that this magic variable would make error handling much more easier.
What do you think?
Best wishes
Marius Spix
Sorry, but it looks really confusing to have a statement
return 10 / x which does not (let us say) raise an exception, yet does
not represent the actual value returned by the function. Sure, you can
already do this: def f(x): try: return 1 # Does not return except
Exception: pass finally: return 2 # Actually returns 2 but it is IMO
emphatically not something that should be encouraged. Best wishes Rob
Cliffe
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