[swift-evolution] Modernize Switch/Case Statements?

[Allen Ding]

I often do something similar to:

```
[ UILabel(), UILabel() ].forEach {
    view.addSuperview($0)
    $0.text = "foo"
}
```

Never used it for single items though. But very useful for building
complicated attributed strings.

On Mon, Feb 1, 2016 at 3:02 AM, Radosław Pietruszewski <
swift-evolution at swift.org> wrote:

> // this is how I have to do things now
> let _ : UILabel = {
> view.addSubview($0)
> CenterViewInSuperview($0,
> horizontal: true, vertical: false)
> $0.text = "Toggle me"
> $0.font = UIFont.boldSystemFontOfSize(36)
> ConstrainViews("V:[view1]-30-[view2]",
> views: $0, mySwitch)
> return $0
> }(UILabel())
> // vs (this does not exist in the language)
> do {
> view.addSubview($0)
> CenterViewInSuperview($0,
> horizontal: true, vertical: false)
> $0.text = "Toggle me"
> $0.font = UIFont.boldSystemFontOfSize(36)
> ConstrainViews("V:[view1]-30-[view2]",
> views: $0, mySwitch)
> }(UILabel())
>
>
>
> That’s an interesting pattern. I don’t think I’ve seen that one before.
>
> How about:
>
> do {
> let v = UILabel()
> view.addSubview(v)
> CenterViewInSuperview(v,
> horizontal: true, vertical: false)
> v.text = "Toggle me"
> v.font = UIFont.boldSystemFontOfSize(36)
> ConstrainViews("V:[view1]-30-[view2]",
> views: v, mySwitch)
> }
>
>
> Is it too bad? I certainly like it better because you introduce `v` ($0)
> at the beginning of the block, not at the end.
>
> And while one letter variable name is kinda gross in general, I don’t mind
> it in such context just like I don’t have a problem with $0 in simple
> closures. It’s a common practice in Ruby, for example, that doesn’t have $x
> to define “obvious” closure arguments as one letter variables, like so:
>
>    articles = article_data.map { |a| Article.new(a) }
>
> — Radek
>
> On 31 Jan 2016, at 18:27, Erica Sadun via swift-evolution <
> swift-evolution at swift.org> wrote:
>
>
> On Jan 31, 2016, at 1:34 AM, Thorsten Seitz via swift-evolution <
> swift-evolution at swift.org> wrote:
>
>
>
> Am 30.01.2016 um 10:39 schrieb Haravikk via swift-evolution <
> swift-evolution at swift.org>:
>
> Actually, one thing we don’t have in Swift is the ability to just put
> blocks (curly braces) wherever we like, which in some languages is a useful
> tool for variable scope when you know you only need something for a short
> time, but might want to re-use the name.
>
>
> You can use a "do" block for that.
>
> do { ... }
>
> -Thorsten
>
>
> do blocks don't let you introduce parameters for short-lived items:
>
> // this is how I have to do things now
> let _ : UILabel = {
> view.addSubview($0)
> CenterViewInSuperview($0,
> horizontal: true, vertical: false)
> $0.text = "Toggle me"
> $0.font = UIFont.boldSystemFontOfSize(36)
> ConstrainViews("V:[view1]-30-[view2]",
> views: $0, mySwitch)
> return $0
> }(UILabel())
> // vs (this does not exist in the language)
> do {
> view.addSubview($0)
> CenterViewInSuperview($0,
> horizontal: true, vertical: false)
> $0.text = "Toggle me"
> $0.font = UIFont.boldSystemFontOfSize(36)
> ConstrainViews("V:[view1]-30-[view2]",
> views: $0, mySwitch)
> }(UILabel())
>
> -- E
>
>
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