[swift-evolution] constant var

[Rafael Guerreiro]

You actually need a class to wrap the dictionary.
That’s because dictionaries are struct, with copy-on-write.

With a class, you’ll be able to have it mutable, in a let declaration.
On Mon, Dec 11, 2017 at 11:34 PM Inder Kumar Rathore . via swift-evolution <
swift-evolution at swift.org> wrote:

> Hi All,
> Today I was writing code and faced a situation where I need to make a
> instance variable a const i.e. it shouldn't accept new values from anywhere
> but the problem is that I want it's content to be mutable.
>
> e.g.
>
> class MyClass {
>   var myDict = [String : String]()
> }
>
>
> I want above variable to be constant and if I make it like below
>
> class MyClass {
>   let myDict = [String : String]()
> }
>
> Then I cann't add key/value in the myDict like
>
>    self.myDict["name"] = "Rathore"
>
>
> I know swift and couldn't find anything related to this.
>
> Can anybody help me?
>
>
> If there is no such method of doing it then I would suggest to either use
> a syntax like
>
> class MyClass {
>   const var myDict = [String : String]()
> }
>
> I'm not using *final *here since that make a var not overridable.
>
>
>
> --
> Best regards,
> Inder Kumar Rathore
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> swift-evolution at swift.org
> https://lists.swift.org/mailman/listinfo/swift-evolution
>
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