[swift-evolution] Extending the for loop to have multiple clauses

[ilya]

>  the second clause can depend on the first...

For those cases, I'd really prefer plain dumb old for loop on two separate
visually distinct lines :)

On Thu, Dec 10, 2015 at 12:13 AM, Chris Eidhof via swift-evolution <
swift-evolution at swift.org> wrote:

> Yes, it’d be great if you can combine it with where. Alternatively, it
> could be interesting to instead explore array comprehension syntax, rather
> than making `for` smarter. That’d allow for a more functional style. For
> example, Norvig’s spelling corrector (http://norvig.com/spell-correct.html)
> would then be very straightforward to port.
>
> Re the x operator: it’s even easier if you define it with flatMap.
> However, the for syntax is different, because the second clause can depend
> on the first...
>
> Chris
>
>
> On 09 Dec 2015, at 15:48, Jacob Bandes-Storch <jtbandes at gmail.com> wrote:
>
> Are you expecting that this could be combined with "where" clauses?
>
> for x in range1 where x%2==0, y in range2 where y%3==0 {}
>
> for x in range1, y in range2 where x%2==0 && y%3==0 {}
>
> I think it's a good idea, but the implications may be less than obvious.
> On Wed, Dec 9, 2015 at 12:37 PM krzysztof at siejkowski.net via
> swift-evolution <swift-evolution at swift.org> wrote:
>
>> +1. Way more readable than nested loops and consistent with already
>> existing syntax.
>>
>>
>> -----Original Message-----
>> From: Chris Eidhof via swift-evolution <swift-evolution at swift.org>
>> Reply: Chris Eidhof <chris at eidhof.nl>
>> Date: December 9, 2015 at 9:00:26 PM
>> To: swift-evolution at swift.org <swift-evolution at swift.org>
>> Subject:  [swift-evolution] Extending the for loop to have multiple
>> clauses
>>
>> > I think it could be really nice to extend the for-loop so that it can
>> have multiple clauses.
>> > Much like in the if-let with multiple clauses, I could imagine a
>> for-loop with multiple
>> > clauses:
>> >
>> > var cards: [(Suit,Rank)] = []
>> > for x in suits, y in ranks {
>> > cards.append((x,y))
>> > }
>> >
>> > This would be the same as writing:
>> >
>> > var cards: [(Suit,Rank)] = []
>> > for x in suits {
>> > for y in ranks {
>> > cards.append((x,y))}
>> > }
>> > }
>> >
>> > You could also do something like:
>> >
>> > for x in input1, y in (x..> // Do something with (x,y)
>> > }
>> >
>> > In fact, once we would have that, we could combine both if-let and for,
>> and make it more
>> > general, to end up with something like Haskell’s do-notation or C#’s
>> LINQ. But that might
>> > be taking it too far...
>> >
>> > Chris
>> > _______________________________________________
>> > swift-evolution mailing list
>> > swift-evolution at swift.org
>> > https://lists.swift.org/mailman/listinfo/swift-evolution
>> >
>>
>> _______________________________________________
>> swift-evolution mailing list
>> swift-evolution at swift.org
>> https://lists.swift.org/mailman/listinfo/swift-evolution
>>
>
>
> _______________________________________________
> swift-evolution mailing list
> swift-evolution at swift.org
> https://lists.swift.org/mailman/listinfo/swift-evolution
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.swift.org/pipermail/swift-evolution/attachments/20151210/6e53e8a0/attachment.html>