[Python-ideas] except expression

[Ram Rachum]

I'm happy you're for it. Maybe one day we'll see a Python 4 with no second
argument to dict.get, getattr and so many others...


On Thu, Feb 13, 2014 at 2:08 AM, Raymond Hettinger <
raymond.hettinger at gmail.com> wrote:

>
> On Feb 12, 2014, at 9:02 PM, Ram Rachum <ram.rachum at gmail.com> wrote:
>
> Here's an idea that would help shortening code. Allow a ternary expression
> based on except, like so:
>
>     first_entry = entries[0] except IndexError else None
>     item = my_queue.get() except queue.Empty else None
>     response_text = request('http://whatever.com').text except HttpError
> else "Can't access data"
>
> Aside from the fact that this would be a big grammar addition, a big
> problem here is the usage of the `else` keyword, that when used with except
> usually means "what would happen if there wasn't an exception" and here
> means the opposite. But I couldn't think of a nicer syntax.
>
> I realize that this is a big change and that most people would be opposed
> to this... But I guess I just wanted to share my idea :)
>
>
> I would like to see something like this come to fruition.
> We need a clean way to express the idea of "take an
> arbitrary, exception-raising function and give it a default
> argument".
>
> Hopefully, this would end the gradual but never-ending requests
> to bloat APIs with "default" arguments.   For example, if your idea
> or some variant had been in place, the min() and max() functions
> likely wouldn't have grown complex signatures in Python 3.4.
>
>
> Raymond
>
>
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