Strong +1. I really need this feature to improve and simplify my existing code.
> On Sep 23, 2016, at 5:50 PM, Austin Zheng via swift-evolution > <swift-evolution@swift.org> wrote: > > * What is your evaluation of the proposal? > > +1. I very much want to see this in Swift, and it seems like a logical > progression that has the potential to eliminate ugly workarounds. > > * Is the problem being addressed significant enough to warrant a change to > Swift? > > Yes. Right now the desired relationships between the associated types of a > protocol must be written out at each site of use (for example, a generic > function declaration that involves that protocol type). When defining a type > that conforms to such a protocol these relationships must either be > discovered through documentation, or by examining the APIs with which the > conforming type will be used. > > By changing this implicit contract (through documentation + use site > constraints) into an explicit contract (through constraints directly > expressed at the point where the associated types are defined), programmers > seeking to write conforming types have an easier time understanding how the > protocols they are conforming to are intended to work, and programmers > seeking to write APIs involving those protocols don't need to spell out the > constraints repeatedly. > > * Does this proposal fit well with the feel and direction of Swift? > > Yes. We already have a pretty regular regime for the use of `where` to define > constraints, for example in generic type and function declarations and when > defining constrained extensions. Adding support for `where` to associated > types would be a natural extension of the existing ability to specify > protocol conformance, and its semantics would not be surprising to those > familiar with the other uses of `where`. (This comment I think applies to all > three of the proposed syntaxes.) > > * If you have used other languages or libraries with a similar feature, how > do you feel that this proposal compares to those? > > n/a > > * How much effort did you put into your review? A glance, a quick reading, or > an in-depth study? > > Read the review, followed most of the pertinent threads over the past few > months with varying degrees of attentiveness. > _______________________________________________ > swift-evolution mailing list > swift-evolution@swift.org > https://lists.swift.org/mailman/listinfo/swift-evolution _______________________________________________ swift-evolution mailing list swift-evolution@swift.org https://lists.swift.org/mailman/listinfo/swift-evolution
