[Python-ideas] Modern language design survey for "assign and compare" statements

Rhodri James rhodri at kynesim.co.uk
Mon May 21 09:14:32 EDT 2018

On 21/05/18 12:29, Daniel Moisset wrote:
> On 21 May 2018 at 12:05, Rhodri James <rhodri at kynesim.co.uk> wrote:
>> Thanks for the analysis, but I'm afraid I must disagree with your
>> recommendation.  It was the thought I first had when Chris came out with
>> his first draft of the PEP several months ago, but it's not enough to cope
>> with my usual use cases.  What I normally want is the Python equivalent of:
>>    while ((v = get_something()) != INCONVENIENT_SENTINEL)
>>      do_something(v);
>> The condition expression itself is not what I want to capture; I need a
>> subexpression, which the "as" syntax won't give me.
> That use case should be covered by
> for v in iter(get_something, INCOVENIENT_SENTINEL):
>      do_something(v)

There are many ways round my use case, all of them inelegant.  That has 
to be one of the less comprehensible alternatives.

Rhodri James *-* Kynesim Ltd

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