[Python-ideas] for/else statements considered harmful

Alice Bevan–McGregor alice at gothcandy.com
Thu Jun 7 17:52:10 CEST 2012

On 2012-06-07 15:30:11 +0000, Mike Meyer said:
> Calling it "wrap-up processing" seems likely to cause people to think
> about it as meaning "finally". But if the else clause is not executed
> if the except clause is (as done by try/except/else), then there's no
> longer an easy way to describe it.
> It seems like adding an except would change the conditions under which
> the else clause is executed (unlike try/except/else), as otherwise
> there's no easy way capture the current behavior, where else is
> executed whenever there are no chunks left to process. But that kind
> of things seems like a way to introduce bugs.

Well, how about:

    for <var> in <iterable>:
        pass # process each <var>
    except:  # no arguments!
        pass # nothing to process
        pass # fell through
        pass # regardless of break/fallthrough/empty

Now for loops perfectly match try/except/else/finally!  >:D  (Like 
exception handling, finally would be called even with an inner return 
from any of the prior sections.)

	— Alice.

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