[swift-evolution] [Review] SE-0065 A New Model for Collections and Indices

[Dave Abrahams]

on Tue Apr 12 2016, Patrick Smith <swift-evolution at swift.org> wrote:

> +1 to Tony’s naming suggestions, myself preferring move(index:by:), move
> (indexForward:), and move(indexBackward:) as it is the most clear and
> consistent.

Sure, any individual operation in a mutating/nonmutating pair can be
better named if you don't consider how to name the corresponding
operation such that the names preserve the relationship.  How do you
name the nonmutating versions of these?

> As an aside, I am not a fan of the form- prefix, as it feels generic
> without being self explanatory. I think another word would work
> better. 

Yeah, practically everybody including me has the same feeling: there's
probably a better answer out there.  Problem is, what is it?  [There's a
better pair of words, except that we can't use those].

> I won’t bikeshed, 

Please, be my guest and bikeshed.  It's more useful to come up with
alternatives than to simply state dissatisfaction with the status quo.

> but I feel form- feels and reads oddly every time I see it.
>
>     > On Apr 10, 2016, at 2:41 PM, Chris Lattner via swift-evolution
>     <swift-evolution at swift.org> wrote:
>     > 
>     > Hello Swift community,
>     > 
>     > The review of "A New Model for Collections and Indices" begins now and
>     runs through April 18th. The proposal is available here:
>     > 
>     >
>     https://github.com/apple/swift-evolution/blob/master/proposals/0065-collections-move-indices.md
>
>     > 
>     > Reviews are an important part of the Swift evolution process. All reviews
>     should be sent to the swift-evolution mailing list at:
>     > https://lists.swift.org/mailman/listinfo/swift-evolution
>     > or, if you would like to keep your feedback private, directly to the
>     review manager.
>     > 
>     > 
>     > What goes into a review?
>     > 
>     > The goal of the review process is to improve the proposal under review
>     through constructive criticism and, eventually, determine the direction of
>     Swift. When writing your review, here are some questions you might want to
>     answer in your review:
>     > 
>     > * What is your evaluation of the proposal?
>
>     I agree with the general direction and scope of the proposal, but I think
>     the names could use some changes. Specifically, I don’t think the fallback
>     to ‘form’ is required. It would be a significant readability improvement to
>     use a meaningful verb to describe the action of altering the argument. The
>     methods that create new indices probably need a label on the first argument,
>     because otherwise it looks as if the IndexDistance is what is described by
>     ‘index’.
>
>     Proposed:
>
>     func successor(of i: Index) -> Index
>
>     func formSuccessor(i: inout Index)
>
>     Instead, I suggest:
>
>     func successor(of i : Index) -> Index
>
>     func advance(i: inout Index)
>
>     Proposed:
>
>     func index(n: IndexDistance, stepsFrom i: Index) -> Index
>
>     func index(n: IndexDistance, stepsFrom i: Index, limitedBy limit: Index) ->
>     Index
>
>     func formIndex(n: IndexDistance, stepsFrom i: inout Index)
>
>     func formIndex(n: IndexDistance, stepsFrom i: inout Index, limitedBy limit:
>     Index)
>
>     Suggested (taking into account Nate’s suggestion of reversing the order):
>
>     func index(startingAt i: Index, movedBy n: IndexDistance) -> Index
>
>     func index(startingAt i: Index, movedBy n: IndexDistance, limitedBy limit:
>     Index) -> Index
>
>     func move(i : inout Index, by n: IndexDistance)
>
>     func move(i : inout Index, by n: IndexDistance, limitedBy limit: Index)
>
>     Proposed:
>
>     func predecessor(of i: Index) -> Index
>
>     func formPredecessor(i: inout Index)
>
>     Suggested:
>
>     func predecessor(of i: Index) -> Index
>
>     func reverse(i: inout Index)
>
>     I think reversing an index has some nice symmetry with reversing a sequence,
>     but if it seems to confusing, then replace advance and reverse with
>     ‘moveForward’ and ‘moveBackward’.
>
>     - Tony
>
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-- 
Dave