[swift-evolution] [swift-evolution-announce] [Review] SE-0154: Provide Custom Collections for Dictionary Keys and Values

[Dimitri Racordon]

> What is your evaluation of the proposal?

+1

Nevertheless it’s a bit unclear to me what is the impact of these additional collections on the ownership of the dictionary.

> Is the problem being addressed significant enough to warrant a change to Swift?

Yes.

> If you have used other languages or libraries with a similar feature, how do you feel that this proposal compares to those?

Python 3 addressed this issue (w.r.t Python 2) in a similar way, using dict_[keys|values] objects. It is common in that language to manipulate the dict_keys. As they are set-like structures, it allows to efficiently manipulate the keys of a dictionary prior to its access/modification.
The proposal doesn’t elaborate on the use of 

I feel like the proposal’s Dictionary.Keys could benefit from a similar approach, not limiting itself to conforming to Collection.

> How much effort did you put into your review? A glance, a quick reading, or an in-depth study?

A careful reading.