[Python-ideas] except expression

[Nathan Schneider]

On Thu, Feb 13, 2014 at 1:47 PM, spir <denis.spir at gmail.com> wrote:

> On 02/13/2014 07:43 PM, Amber Yust wrote:
>
>> Actually. What if we just reused 'try'?
>>
>>      foo = bar() except BazException try 'qux'
>>
>> This also leads naturally to chaining multiple possible fallbacks:
>>
>>      foo = bar() except BarException try baz() except BazException try
>> None
>>
>
> I like it. Especially because 'try' already works with 'except'. (But note
> that 'try', like my proposal of 'then', normally introduces a block).
>
>
This strikes me as counterintuitive because it is inconsistent: 'bar()' is
being tried, but does not follow 'try', while the others do. And then the
'try None' has no corresponding 'except'.

Suggestion: an expression like

    foo = (try bar() except BarException)

that defaults to None if the exception is caught. This could then be
chained with 'or':

    foo = (try bar() except BarException) or (try baz() except BazException)

as distinguished from

    foo = (try bar() except BarException) or baz()

which does not do any exception handling for baz().

(Apologies if something like this has been proposed above; I could not find
it from skimming the thread.)

Nathan


>
> d
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