while loop with the condition used in the body

[Peter Otten]

Duncan Booth wrote:

> Peter Otten <__peter__ at web.de> wrote:
> 
>> Ulrich Eckhardt wrote:
>> 
>>> I'm looking for a way to write code similar to this C code:
>>> 
>>>   while(rq = get_request(..)) {
>>>      handle_request(rq);
>>>   }
>>> 
>> Assuming get_request(...) is called with the same arguments on each
>> iteration and uses None to signal that there is no more data:
>> 
>> from functools import partial
>> 
>> for rq in iter(partial(get_request, ...), None):
>>     handle_request(rq)
>> 
>> Peter
> 
> and the next step on from this is to realise that the problem isn't how to
> code the calls to get_request(), the problem is actually that
> get_request() itself isn'ty Pythonic. Rewrite it as a generator, rename it
> to reflect that it now generates a sequence of requests and the code
> becomes:
> 
> for rq in incoming_requests(...):
>    handle_request(rq)

...and a likely implementation would be

def incoming_requests(...):
    while True:
        rq = ... # inlined version of get_request()
        if not rq:
            break
        yield rq

In other words: It's turtles all the way down...

Peter