[swift-evolution] What about a VBA style with Statement?

[Sean Heber]

This pair works pretty well, too, if you don’t mind free functions:

func with<T>(inout this: T, @noescape using: inout T->Void) { using(&this) }
func with<T>(this: T, @noescape using: T->Void) { using(this) }

It works either with classes or mutable structs if you call it correctly and the type doesn’t matter.

l8r
Sean


> On Apr 13, 2016, at 9:17 AM, Radosław Pietruszewski via swift-evolution <swift-evolution at swift.org> wrote:
> 
> It can be (more-or-less) solved in library code today:
> 
> extension NSObjectProtocol {
>     public func with(@noescape fn: Self -> Void) -> Self {
>         fn(self)
>         return self
>     }
> }
> 
> This way, you can do, on NSObjects:
> 
> textLabel.with {
> 	$0.textAlignment = .Left
> 	$0.textColor = .darkTextColor()
> }
> 
> I love this pattern.
> 
> You can also make it a function to make it work with any value of any kind (it will then take form of `with(foo) { …}`).
> 
> Ideally, if you could write a universal extension (something like `extension Any`), you could just add this behavior, with method syntax, to everything.
> 
> — Radek
> 
>> On 13 Apr 2016, at 15:15, 李海珍 via swift-evolution <swift-evolution at swift.org> wrote:
>> 
>> I recently learned some VBA and I found a very conveniently `with` statement.
>> 
>> `with` statement can be helpful to set property for UIKit instance.
>> 
>> for instance a UILabel instance `textLabel` ,with `with` statement we can set UILabel property like this
>> 
>> 
>> 
>> ```swift
>> 
>> with textLabel{
>> 
>> .textAlignment = .Left
>> 
>> .textColor = UIColor.darkTextColor()
>> 
>> .font = UIFont.systemFontOfSize(15)
>> 
>> }
>> 
>> ```
>> 
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