[swift-evolution] [Pitch] Remove destructive consumption from Sequence

[Jonathan Hull]

> On Jun 28, 2016, at 10:51 AM, Dave Abrahams <dabrahams at apple.com> wrote:
> 
>>> 1. Presumably these are all for-in-able.  What makes something
>>>  for-in-able?
>> 
>> I would think the potentially infinite should require for-in-until
>> (even if you explicitly set until to false to create an infinite
>> loop), but collection would allow for-in (with optional until).  That
>> way you have to acknowledge the possibility of an infinite
>> sequence/iterator.
> 
> Are you proposing a new language feature?  We could also do this with
> 
>    for i in allIntegers.until(isPrime)

I was, but I think I would be ok with this too, as long as the compiler caught the issue and suggested a fix.  The key is that we are forced to deal with the possibility of an infinite sequence/iterator.  Also:

for i in infSequence.maxLoops(3000)  //or a better name for this idea

Thanks,
Jon
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