[swift-evolution] [Pitch] Retiring `where` from for-in loops

[Jean-Daniel Dupas]

-1 for the removal.

When I read code, I find it far more visible that a loop is over a filter list when the filter clause is on the same line, than when the filter clause is inside the loop.

Having to read the full content of the loop to determine if the list is filtered or not is not an improvement IMHO.

Moreover, I find it far cleaner to use the where clause that having to remember than I have to use the lazy accessor to avoid a performance hit.

> Le 13 juin 2016 à 06:39, Charlie Monroe via swift-evolution <swift-evolution at swift.org> a écrit :
> 
>> And to follow-up to myself once again, I went to my "Cool 3rd Party Swift Repos" folder and did the same search. Among the 15 repos in that folder, a joint search returned about 650 hits on for-in (again with some false positives) and not a single for-in-while use.
>> 
>> -- E
> 
> Not to undermine this fact, but I believe the fact that `where` can be used in a for loop is not widely known. I didn't know about it until about a month ago (haven't really read much docs, but most people don't either).
> 
> But after I found out about it, I started using it and it IMHO improved readability of my code. Not by much, but it's the little things that make you smile, right?
> 
> Many people here argument that `where` is a Swift speciality and needs to be learned by the developer - the alternative is to teach the person what's the proper alternative - that using .filter can have performance impact and that the *correct* way is to use guard within the for loop. And that's IMHO much worse than teaching a person about using `where` within a for loop.
> 
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