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

[krzysztof@siejkowski.net]

+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
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