[swift-evolution] ed/ing, InPlace, Set/SetAlgebra naming resolution
Dave Abrahams
dabrahams at apple.com
Sun Feb 14 10:10:22 CST 2016
on Sat Feb 13 2016, Ricardo Parada <rparada-AT-mac.com> wrote:
> Hi Dave,
>
> I would be okay with staying away from the mathematical terms similar
> to what you are suggesting except that the union can still be made
> more concise if you use merged / merge for the base name and shorten
> the labels to a bare minimum without loosing clarity. In addition,
> the merge can have a second parameter with a default to false in order
> to implement the symmetric difference (a.k.a. exclusive or). Recall
> that symmetric difference is the union of two sets and then removing
> the intersection (or members in common). I think it looks perfect
> (concise and clear). What does everybody else think?
>
> Non-mutable
>
> let union = a.merged(with: b)
> let intersection = a.members(in: b)
> let difference = a.removingMembers(in: b)
> let symmetricDifference = a.merged(with: b, removingMembersInCommon: true)
>
> Mutable (In-Place)
>
> a.merge(with: b) // union in-place
> a.removeMembers(notIn: b) // intersect in-place
> a.removeMembers(in: b) // difference in-place
> a.merge(with: b, removeMembersInCommon: true) // symmetric difference in-place
I love your changes to my suggestion, Ricardo! The minor alterations I
would make are:
1. In both cases the Bool parameter ought to be called
“removingMembersInCommon”
2. I would remove “with” from the in-place merge operation. We're
really asking the receiver to merge b into itself. “With” gives it
the sense that it might almost be mutating b.
> Ricardo Parada
>
>> On Feb 13, 2016, at 1:16 PM, Dave Abrahams via swift-evolution <swift-evolution at swift.org> wrote:
>>
>>
>> on Fri Feb 12 2016, Ricardo Parada <swift-evolution at swift.org
>> <mailto:swift-evolution at swift.org>> wrote:
>>
>>> Hi all,
>>>
>>> I can’t make up my mind. Let me propose two different alternatives
>>> that I’m not sure if they have been considered:
>>>
>>> ALTERNATIVE 1
>>>
>>> Non-mutable (noun-based)
>>>
>>> - func union(other: Self) -> Self
>>> + func union(other: Self) -> Self Assumes union is a noun, i.e. not a verb
>>>
>>> - func intersect(other: Self) -> Self
>>> + func intersection(other: Self) -> Self
>>>
>>> - func subtract(other: Self) -> Self
>>> + func subtraction(other: Self) -> Self
>>>
>>> - func exclusiveOr(other: Self) -> Self
>>> + func symmetricSubtraction(other: Self) -> Self
>>>
>>> Mutable (verb-based)
>>>
>>> - mutating func unionInPlace(other: Self)
>>> + mutating func unite(other: Self)
>>>
>>> - mutating func intersectInPlace(other: Self)
>>> + mutating func intersect(other: Self)
>>>
>>> - mutating func subtractInPlace(other: Self)
>>> + mutating func subtract(other: Self)
>>>
>>> - mutating func exclusiveOrInPlace(other: Self)
>>> + mutating func symmetricSubtract(other: Self)
>>>
>>> Comments:
>>>
>>> With this alternative we keep the union name which I assume is
>>> popular. However, one has to accept unite as a verb (for the mutable
>>> version) as I wanted all the mutable methods use verbs for
>>> consistency. I think unite is acceptable because it can be found in
>>> the dictionary and it is a verb.
>>>
>>> Notice that all the non-mutable methods use nouns: union,
>>> intersection, subtraction and symmetricSubtraction.
>>>
>>> I understand some may oppose to symmetricSubtraction saying that
>>> symmetricSubraction is not as common as "exclusive or". However,
>>> using symmetricSubtraction is consistent with subtraction and it hints
>>> to a variation of the “subtraction" operation. We will get used to it
>>> quickly / easily.
>>>
>>> The mutable methods all use verbs: unite, intersect, subtract and symmetricSubtract.
>>>
>>> ALTERNATIVE 2
>>>
>>> Non-mutable
>>>
>>> - func union(other: Self) -> Self
>>> + func adding(other: Self) -> Self
>>>
>>> - func intersect(other: Self) -> Self
>>> + func intersecting(other: Self) -> Self
>>>
>>> - func exclusiveOr(other: Self) -> Self
>>> + func exclusiveOring(other: Self) -> Self
>>>
>>> - func subtract(other: Self) -> Self
>>> + func removing(other: Self) -> Self
>>>
>>> Mutable
>>>
>>> - mutating func unionInPlace(other: Self)
>>> + mutating func add(other: Self)
>>>
>>> - mutating func intersectInPlace(other: Self)
>>> + mutating func intersect(other: Self)
>>>
>>> - mutating func exclusiveOrInPlace(other: Self)
>>> + mutating func exclusiveOr(other: Self)
>>>
>>> - mutating func subtractInPlace(other: Self)
>>> + mutating func remove(other: Self)
>>>
>>> Comments: This alternative gives up on union in favor or add. Many
>>> may not like this, that is why I have it as the second alternative.
>>> It brings back exclusiveOr and treats it as a verb. Some may argue
>>> that exclusiveOr is a noun for the "exclusive or" operation.
>>
>> If we are going to force Set fit the naming guidelines, I would prefer
>> to stay away from the mathematical terms altogether.
>>
>> func insertingContentsOf(other: Self) -> Self // union
>> mutating func insertContentsOf(other)
>>
>> func members(in other: Self) -> Self // intersection
>> mutating func removeMembers(notIn: other)
>>
>> func removingMembersAndAddingNonMembers(in other: Self) -> Self // symmetric difference
>> mutating func removeMembersAndAddingNonMembers(in other: Self)
>>
>> func removingMembers(in other: Self) -> Self // subtract
>> mutating func removeMembers(in other: Self)
>>
>> If it would help with clarity, we could replace "in" with "foundIn"
>> above.
>>
>> --
>> -Dave
>>
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--
-Dave
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