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

[Radosław Pietruszewski]

> On 13 Apr 2016, at 16:47, Vladimir.S <svabox at gmail.com> wrote:
> 
> Than you for sharing this method. So, do you suggest to not have this "with" construction in Swift just because we *can* implement the same behavior by using some workarounds/hacks?
> 
> I.e. do you support this proposal or don't?
> Do you agree that such built-in feature will be very useful and make our programming live a little better/easier?

I’m -1, at least in the foreseeable future. I do agree that this is a useful construct, but if I can do it in library code, paying only a small price for this, I’d prefer Swift to grow better in places that a library *can’t* fix.

> 
> I strongly believe that if such feature is really useful and handy, if it is explicit and if it is clearly showing in code what we are doing - we most likely want to have this feature as part of language rather than possibility to use some workaround to implement it.
> 
> With your suggestion, how to deal with two separate classes that have no common protocol? I.e.
> class A { .. }; class B {..};
> Should we conform them to some protocol or create extension of each just to have this "with" feature? Don't think so.

No — for now, it’s best to use a free function for now. And, like I mentioned, universal conformances could allow this to be easily added to all types — and so I’d focus on pushing *that* proposal.

> 
> On 13.04.2016 17:17, Radosław Pietruszewski via swift-evolution 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 <mailto:swift-evolution at swift.org> <mailto:swift-evolution at swift.org <mailto: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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>> 
>> 
>> 
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