[swift-evolution] [Idea] Add forced conversion for Error catching pattern matching

[Michel Fortin]

Le 20 mars 2016 à 16:26, Tyler Fleming Cloutier via swift-evolution <swift-evolution at swift.org> a écrit :
> 
> Would it be wise to allow force conversion for the cases in which the developer believes the match is exhaustive? ie
> 
> do {
>     let action = chooseAction(game)
>     game = try game.applyAction(action)
> } catch let e as ActionError {
>     game.failedAction = e
> } catch _ {
>     fatalError(“This is an unfortunate bit of noise :/")
> }
> 
> becomes
> 
> do {
>     let action = chooseAction(game)
>     game = try game.applyAction(action)
> } catch let e as! ActionError {
>     game.failedAction = e
> }

If you move the cast on the next line it'll compile and do what you want with exactly the same amount of code:

	do {
	    let action = chooseAction(game)
	    game = try game.applyAction(action)
	} catch let e {
	    game.failedAction = e as! ActionError
	}


-- 
Michel Fortin
https://michelf.ca