[swift-evolution] Proposal: An assignment operator := that ensures nil before assignment.

[Amir Michail]

> On Feb 27, 2016, at 11:07 AM, Stephen Celis <stephen.celis at gmail.com> wrote:
> 
> 
>> On Feb 27, 2016, at 10:57 AM, Amir Michail <a.michail at me.com> wrote:
>> 
>>> On Feb 27, 2016, at 10:39 AM, Stephen Celis <stephen.celis at gmail.com> wrote:
>>> 
>>>> On Feb 27, 2016, at 10:38 AM, Amir Michail <a.michail at me.com> wrote:
>>>> 
>>>> I think this := would be used so often that it should be part of the language/standard library.
>>> 
>>> Would you please justify this? Would you please answer the questions from my reply?
>> 
>> See: http://research.microsoft.com/apps/pubs/default.aspx?id=70290
> 
> See what part? This document provides no justification for any kind of assignment/assertion operator. Please provide additional context around links you share and how they relate to your actual proposal.

The justification for assertions in general is empirical and the Microsoft paper provides it.

To explore how useful := assertions are in particular would need a study like the Microsoft one that focuses exclusively on := assertions.

> 
> In this case your proposal still needs justification. Would you, again, please answer these questions to provide it?
> 
> - Why do you want this feature?
> 
> - Would you please provide a better, real-world example (perhaps code extracted from a real-world project you've worked on that would benefit) that demonstrates the benefits of your suggestion?
> 
> - Can you go into more detail on the the design of the proposal? How it may be implemented? Caveats? Alternatives considered?
> 
> --
> Stephen