[swift-evolution] ed/ing, InPlace, Set/SetAlgebra naming resolution

Tyler Fleming Cloutier cloutiertyler at aol.com
Sun Feb 14 15:13:18 CST 2016


> On Feb 14, 2016, at 12:48 PM, Dave Abrahams <dabrahams at apple.com <mailto:dabrahams at apple.com>> wrote:
> 
> 
> on Sun Feb 14 2016, Tyler Fleming Cloutier <cloutiertyler-AT-aol.com <http://cloutiertyler-at-aol.com/>> wrote:
> 
>>> On Feb 14, 2016, at 8:27 AM, Dave Abrahams <dabrahams at apple.com <mailto:dabrahams at apple.com>> wrote:
>>> 
>>> 
>>> on Sat Feb 13 2016, Tyler Fleming Cloutier <cloutiertyler-AT-aol.com <http://cloutiertyler-at-aol.com/>> wrote:
>>> 
>>>> I would, personally, be very careful about discarding the mathematical
>>>> terms since they are so widely used and understood.
>>> 
>>> IMO it's better to leave them aside than to use them in “creative” ways
>>> that might be misleading.
>>> 
>> 
>> Agreed. I’m all for that.
>> 
>>>> One issue is that it’s going to be hard to search for the operation I
>>>> want considering I won’t be looking for "func
>>>> invertingMembershipOfContentsOf(other: Self) -> Self”. I’m concerned
>>>> people are going to have to do mental gymnastics to build the map from
>>>> math term to Swift function every time they want to look for a set
>>>> operation method. “func invertingMembershipOfContentsOf(other: Self)
>>>> -> Self” doesn’t exactly seem to fit in the commonly held Venn diagram
>>>> mental model of set operations. You could always have a documentation
>>>> comment that specifies the mathematical term so that people didn’t
>>>> have to double check themselves every time.
>>>> 
>>>> That being said, if the autocomplete issue is not a concern, I’m of
>>>> the opinion that the names Ricardo proposed are short, clear, and are
>>>> not so hard to fit to my Venn diagram mental model.
>>> 
>>> +1
>>> 
>>>> However, I tend to think that if there has to be this much dancing to
>>>> name a set of fundamental operations, the guidelines aren’t
>>>> accomplishing their goal. 
>>> 
>>> I can't disagree.
>>> 
>>>> It’s going to make it that much harder for people do design their own
>>>> APIs. I'm having quite a time trying to conform Mattt’s Surge API to
>>>> the guidelines.
>>> 
>>> Please explain in detail.  Without details we don't know what's wrong
>>> with the guidelines.
>> 
>> Ah, I apologize. I’ve gone into detail about this API on the list
>> before, but I should have included the details here.
>> 
>> Here are my previous posts:
>> https://lists.swift.org/pipermail/swift-evolution/Week-of-Mon-20160118/007560.html <https://lists.swift.org/pipermail/swift-evolution/Week-of-Mon-20160118/007560.html>
>> <https://lists.swift.org/pipermail/swift-evolution/Week-of-Mon-20160118/007560.html <https://lists.swift.org/pipermail/swift-evolution/Week-of-Mon-20160118/007560.html>>
>> 
>> Basically the issues come down to the following. The Accelerate
>> framework typical operates in a non-mutating way. This means that my
>> API only has non mutating member functions and I should use the ed/ing
>> rule according to the guidelines to name my methods.
>> 
>> This is very difficult for some methods. I’m able to frequently get
>> around the problem for things like “sin” or “arctan” by keeping them
>> as global functions, but I can’t do that for a number of
>> methods. Consider:
>> 
>> remainder
>> dot (returns a scalar, thus there can’t be a mutating version, so
>> should I just call it dot? Guidelines don’t really comment on this)
>> mean (same as above)
>> cross
>> reciprocal
>> threshold
>> copysign
>> fastFourierTransform
>> pow (arguably the method version should be called raisedTo)
>> 
>> I could force all these to be global functions only, but these are not
>> as cut and dry as “sin” or “arctan”. I feel like I’d be splitting my
>> API up into two parts just based on the fact that it’s difficult to
>> use the ed/ing rule. That makes it very difficult for users to find
>> certain functions in my API.
>> 
>> In this case there are no corresponding mutating operations because of
>> the way Accelerate works, but one could certainly imagine an API with
>> mutating counterparts. The way I read the guidelines, they seem to
>> imply I should use ed/ing regardless of whether there is a mutating
>> counterpart. I’d love to hear your thoughts on this.
> 
> As long as the ones without side effects read as noun phrases and the
> ones with side-effects read as verb phrases, you're good.  No ed/ing
> needed.
> 

Ah yes, you are very right. Still what would the mutating versions of remainder, fastFourierTransform, or reciprocal be? getRemainder? applyFastFourierTransform? reciprocate? I suppose those aren’t so bad.

I also suppose cross could become x.crossProduct(with: y) and copysign, x.copyingSign(of: y). Seems a little verbose, but it does the job.

Thanks,

Tyler


> 
>> 
>> 
>> Thanks,
>> 
>> Tyler
>> 
>>> 
>>>> 
>>>> Tyler
>>>> 
>>>>> On Feb 13, 2016, at 9:09 PM, Ricardo Parada via swift-evolution <swift-evolution at swift.org <mailto:swift-evolution at swift.org>> 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
>>>>> 
>>>>> Ricardo Parada
>>>>> 
>>>>> 
>>>>>> On Feb 13, 2016, at 1:16 PM, Dave Abrahams via swift-evolution
>>>>>> <swift-evolution at swift.org <mailto:swift-evolution at swift.org> <mailto:swift-evolution at swift.org <mailto:swift-evolution at swift.org>>>
>>>>>> wrote:
>>>>>> 
>>>>>> 
>>>>>> on Fri Feb 12 2016, Ricardo Parada <swift-evolution at swift.org <mailto:swift-evolution at swift.org>
>>>>>> <mailto: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
>>>>>> 
>>>>>> _______________________________________________
>>>>>> swift-evolution mailing list
>>>>>> swift-evolution at swift.org <mailto:swift-evolution at swift.org> <mailto:swift-evolution at swift.org <mailto:swift-evolution at swift.org>>
>>>>>> https://lists.swift.org/mailman/listinfo/swift-evolution <https://lists.swift.org/mailman/listinfo/swift-evolution>
>>>>>> <https://lists.swift.org/mailman/listinfo/swift-evolution>
>>>>> _______________________________________________
>>>>> swift-evolution mailing list
>>>>> swift-evolution at swift.org <mailto:swift-evolution at swift.org>
>>>>> https://lists.swift.org/mailman/listinfo/swift-evolution
>>>> 
>>> 
>>> -- 
>>> -Dave
>> 
> 
> -- 
> -Dave

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