[swift-evolution] Inconsistencies related to prepositions

[Goffredo Marocchi]

Thank you for the long reply, I do agree that I could have been more
constructive and what I said could have been more on point with the thread
at hand and better argued. I do like a complete and well written rebuttal,
chance for me to learn from it :).

On Thu, Aug 3, 2017 at 5:14 PM, Austin Zheng <austinzheng at gmail.com> wrote:

>
>
> On Thu, Aug 3, 2017 at 8:13 AM, Goffredo Marocchi <panajev at gmail.com>
> wrote:
>
>> Because what is the current idiomatic Swift of today may not be the Swift
>> of tomorrow if people are allowed to keep shaping it as it gets used in the
>> real world. Ideas can be imported from other languages and today's ideas
>> and philosophy are not dogmas.
>>
>
> The problem I see with your email is that it does not contribute anything
> to the discussion.
>
> - We _know_ Swift has an expressivity problem compared to Objective-C,
> many people have made this point loud and clear.
> - There are no useful concrete proposals or suggestions of design
> directions expressed in this email besides the rehashing of a point that
> has been made ad nauseaum on these lists, especially in places more
> appropriate for it (e.g. in proposal reviews that involved strengthening
> the type system).
>
>
>> Swift does value expressiveness, see the use of argument labels which is
>> perhaps more pervasive than it was in Objective-C (even more before the
>> change in argument labels that hit closures and callbacks).
>>
>
> Here is the crux of my disagreement with your email.
>
> Method naming conventions and static typing can be adjusted nearly
> independently of one another, and bringing up the latter in a discussion
> about the former is _not helpful_.
>
> You could remove Swift's type system tomorrow and still improve how
> methods are named. In fact, Swift's current naming conventions are quite
> suited for a dynamic language. You could also strengthen Swift's type
> system and improve method naming conventions. The two do not march in
> lockstep. "Expressiveness" is a huge, vague, and wide-reaching topic.
> Claiming that static typing is an expressiveness concern and therefore that
> complaining about it in a thread that deals with an almost completely
> unrelated feature strikes me as disingenuous. Help me out here.
>
>
>>
>>
>
>> I do not want to add noise to useful discussions so please do not assume
>> the worst in my statements, but I also do not think that the idea of "if
>> you do not like <a>, go back to your <insert expletive> country" has merit
>> or is helpful to the evolution of the language.
>>
>
> Please.
>
> The issue at hand is not "go back to your country", it is "use the right
> tool for the job at hand".
>
> Engineering, like every field of human endeavor, has political elements,
> but it is not itself a fundamentally political endeavor. This gross
> anthropomorphization is beneath both you and I, and is better avoided for
> the happiness of all.
>
> As for contributing to the evolution of the language, your post is not the
> first of its quality, specific form, and sentiment that I've seen on the
> list, but only the first that I've been moved to respond to. So if I can
> steer future discussion in a more productive direction, I will consider
> this email chain to be a net positive, even if I have to send out quite a
> few more of these emails in reply :).
>
> With the utmost respect,
> Austin
>
>
>
>
>> On Thu, Aug 3, 2017 at 3:16 PM, Austin Zheng <austinzheng at gmail.com>
>> wrote:
>>
>>> If you want to use Objective-C you're free to use Objective-C, or more
>>> generally any of the wonderful languages that choose a different tradeoff
>>> regarding convenience over expressiveness. Otherwise, I'm not really sure
>>> what productive forward movement bringing up complaints about a fundamental
>>> philosophical underpinning of Swift that's not realistically going to
>>> change is supposed to achieve. As was mentioned in a message earlier this
>>> week, swift-evolution is a list to discuss making changes to the Swift
>>> language, not a list for ranting about things in Swift you don't like but
>>> cannot change.
>>>
>>> Regards,
>>> Austin
>>>
>>> On Aug 2, 2017, at 11:43 PM, Goffredo Marocchi via swift-evolution <
>>> swift-evolution at swift.org> wrote:
>>>
>>>
>>> Sent from my iPhone
>>>
>>> On 3 Aug 2017, at 04:39, Brent Royal-Gordon via swift-evolution <
>>> swift-evolution at swift.org> wrote:
>>>
>>> On Aug 2, 2017, at 10:49 AM, Xiaodi Wu via swift-evolution <
>>> swift-evolution at swift.org> wrote:
>>>
>>> Brent had a draft proposal to revise the names of collection methods to
>>> improve the situation here. There is room for improvement.
>>>
>>>
>>> It didn't change `remove(at:)`, though. (Well, it might have affected
>>> its return value or something, I don't remember.) It mostly addressed the
>>> `dropLast()`, `prefix(_:)` etc. calls.
>>>
>>> To respond to the original post:
>>>
>>> Some of the APIs you cite are not very well named, but I think your
>>> diagnosis is incorrect and so your prescription isn't going to help.
>>>
>>> The reason for this is, whenever a preposition is used in English, it
>>> almost always takes a dyadic form, relating a subject to the preposition's
>>> object. The two most common dyadic formats are:
>>>
>>> *<subject> [<preposition> <object of preposition>]*
>>> <The boy> [<with> <the dog>] crossed the street.
>>>
>>> *[<preposition> <** object of preposition**>] <subject>*
>>> [<In> <space>], <no one> can hear you scream.
>>> [<On> <the Moon>] are <many craters>.
>>>
>>> Now, in Objective C through Swift 1 and 2, prepositions' dyadic nature
>>> were generally respected in method signatures. However, Swift 3's migration
>>> of the preposition inside the parentheses also seems to have been
>>> accompanied by the stripping away of either the subject, the prepositional
>>> object, or both—according to no discernible pattern. For example:
>>>
>>> (1) CloudKit:
>>>
>>> old: myCKDatabase.fetchRecordWithID(recordID)
>>> new: myCKDatabase.fetch(withRecordID: recordID)
>>> *(subject "Record" got removed)*
>>>
>>>
>>> (2) String:
>>>
>>> old: myString.capitalizedStringWithLocale(_: myLocale)
>>> new: myString.capitalized(with: myLocale)
>>> *(subject "String" and prep. object "Locale" both got removed)*
>>>
>>>
>>> (3) Dictionary:
>>>
>>> old: myDict.removeAtIndex(myIndex)
>>> new: myDict.remove(at: myIndex)
>>> *(subject "element" already missing from both; prep. object "Index" got
>>> removed)*
>>>
>>>
>>> The thing is, the subjects and prepositional objects *are* present in
>>> all of these—they are the parameters and targets of the calls.
>>>
>>> In your own example, you say "In space, no one can hear you scream", not
>>> "In location space, group-of-people no one can hear you scream". So why is
>>> it a problem that we say "myString, capitalized with myLocale" instead of
>>> "myString, string capitalized with locale myLocale"? These are redundancies
>>> that we would never tolerate in natural language; I don't see why you think
>>> code should be different.
>>>
>>> (4) Date:
>>>
>>> old: myDate.timeIntervalSinceDate(myDate)
>>> new: myDate.timeIntervalSince(date: myDate)
>>> *(subject "timeInterval" and object "Date" both still present; but
>>> oddly, preposition "since" got left outside of the parentheses)*
>>>
>>>
>>> This is actually inaccurate—the parameter to `timeIntervalSince(_:)` is
>>> unlabeled, so it's:
>>>
>>> new: myDate.timeIntervalSince(myDate)
>>>
>>> (5) Array:
>>>
>>>     old: myArray.forEach({ thing in code})
>>>
>>> new: myArray.forEach() { thing in //code }
>>>
>>>             *(preposition “for” is outside of the parentheses)*
>>>
>>>
>>> Yes, because the preposition does not apply to the parameter—it applies
>>> to the operation as a whole. I'll have more to say on this in a moment.
>>>
>>> The inconsistency between the examples is shown in the bold text of each
>>> example, but lets go over why this matters. It matters because any language
>>> is easier to learn the more consistently it sticks to its own rules.
>>>
>>>
>>> This is true, but you aren't just proposing sticking more closely to our
>>> existing standards—you're proposing *changing* our standards. And I don't
>>> think the changes you propose are an improvement. In fact, I'd say each of
>>> these examples is worse:
>>>
>>> (1) myCKDatabase.fetchRecord(withRecordID:)
>>>
>>>
>>> "Fetch record with record ID"? I mean, you could at least remove the
>>> `Record` before `ID`. What other ID do you suppose it would be?
>>>
>>> I *can* see the case for going back to `fetchRecord` instead of just
>>> `fetch`, though. On the other hand, I do think that, if you know it's a
>>> database, the most obvious thing for `fetch` to be fetching is a record
>>> from that database. It's not a dog—it won't be fetching a stick.
>>>
>>> (2) myString.stringCapitalized(withLocale:)
>>>
>>>
>>> Let's translate this to an actual use site, which is what we care about.
>>>
>>> func tableView(_: UITableView, titleForHeaderInSection section: Int) ->
>>> String? {
>>> return sections[section].title.stringCapitalized(withLocale: .current)
>>> }
>>>
>>> What is `string` contributing here? We already know it's a "title",
>>> which sounds a lot like a string. If you asked for a "capitalized" string,
>>> what else would you get back if not another string?
>>>
>>> The locale parameter is a little more tricky. You're right that `(with:
>>> .current)` is vague, but I can imagine plenty of call sites where `with`
>>> wouldn't be:
>>>
>>> title.capitalized(with: german)
>>> title.capitalized(with: docLocale)
>>> title.capitalized(with: otherUser.locale)
>>>
>>> Something at the call site needs to imply this is a locale, and there's
>>> nothing in `(with: .current)` that does so. This is arguably just a style
>>> issue, though: even though the language allows you to say `(with:
>>> .current)`, you really ought to say `(with: Locale.current)` to be clearer.
>>> Or perhaps the problem is with the name `current`—it ought to be
>>> `currentLocale` (even though that's redundant when you write it out as
>>> `Locale.currentLocale`), or it should use some location-ish terminology
>>> like `home` or `native`.
>>>
>>> (Actually, I think there might be a new guideline there: Variable and
>>> property names should at least hint at the type of the value they contain.
>>> Names like `current` or `shared` or `default` are too vague, and should
>>> usually be paired with a word that implies the type.)
>>>
>>> It might also help to change the `with` preposition to `in`, which would
>>> at least imply that the parameter is related to some kind of location.
>>>
>>> title.capitalized(in: german)
>>> title.capitalized(in: docLocale)
>>> title.capitalized(in: otherUser.locale)
>>> title.capitalized(in: .current) // Still not great, but better
>>>
>>> (3) myDictionary.elementRemoved(atIndex:)
>>>
>>>
>>> This naming is exactly backwards, and is a perfect example of why we
>>> *don't* want rigid consistency:
>>>
>>> 1. It emphasizes the element being returned, while making the "Removed"
>>> operation an afterthought, even though the removal is the main thing you
>>> want to happen and the element is returned as an afterthought.
>>>
>>> 2. It mentions the "Index", even though there is no other plausible
>>> thing that could be labeled "at". (The only other plausible parameters to a
>>> `remove` method are an element, an array of elements, a predicate, or a
>>> range of indices. Of those four, only the range of indices could possibly
>>> make sense with "at", but that ambiguity is a harmless overloading.)
>>>
>>> Again, think about a use site:
>>>
>>> func tableView(_: UITableView, commit edit: UITableViewCellEditingStyle,
>>> forRowAt indexPath: IndexPath) {
>>> assert(edit == .delete)
>>> sections[indexPath.section].rows.elementRemoved(atIndex: indexPath.row)
>>> // vs.
>>> sections[indexPath.section].rows.remove(at: indexPath.row)
>>> }
>>>
>>> In context, `elementRemoved` obscures the purpose of the line, and there
>>> is no ambiguity about what `at` means. The current name is *far* better.
>>>
>>> (4) myDate.timeInterval(sinceDate:)
>>>
>>>
>>> I have a hard time thinking of a call site where `sinceDate` would be an
>>> improvement over `since`; the preposition already *strongly* implies a
>>> temporal aspect to the parameter.
>>>
>>> If we remove `Date`, then in isolation I kind of like this change. The
>>> problem arrives when you step out of isolation and think about the other
>>> methods in its family. It would be strange to have
>>> `myDate.timeInterval(since: otherDate)`, but `myDate.timeIntervalSinceNow()
>>> `.
>>>
>>> One solution would be to add `now`, `referenceDate`, and `unixEpoch` (or
>>> `utc1970`) as static properties on `Date`. Then you could have just the one
>>> `timeInterval(since:)` method:
>>>
>>> myDate.timeInterval(since: otherDate)
>>> myDate.timeInterval(since: .now)
>>> myDate.timeInterval(since: .referenceDate)
>>> myDate.timeInterval(since: .unixEpoch)
>>>
>>> Another solution would be to add a `-` operator that takes two `Date`s
>>> and returns a `TimeInterval`, sidestepping the wording issue entirely.
>>>
>>> (5) myArray.each(inClosure: )
>>>
>>>
>>> I don't get this name at all. This operation is completely imperative
>>> and side-effectful, but there's no verb? How is it "in" the closure? Why
>>> "closure" when you can pass a function, and in fact you probably will
>>> *only* see this label if you're passing a function?
>>>
>>> I do think there's a problem with `forEach(_:)`—it ought to be
>>> `forEach(do:)`. This is much like `DispatchQueue.async(execute:)` or
>>> the `withoutActuallyEscaping(_:do:)` function in the standard library.
>>> When you pass a function parameter, and the call's primary purpose is to
>>> run that parameter, it's often best to attach the verb to that parameter
>>> instead of putting it in the base name. Of course, the complication there
>>> is that the verb doesn't actually get written if you use trailing closure
>>> syntax, but the curlies sort of fill that role. Kind of.
>>>
>>> Although I do understand removing "string" from the latter was to reduce
>>> redundancy in function/method declarations, we only make one declaration,
>>> yet we make many calls. So increasing ambiguity in calls does not seem like
>>> a good trade-off for decreased boilerplate in declarations. More often than
>>> not it's calls that we're reading, not the declarations—unless of course
>>> the call was ambiguous and we had to read the declaration to make sense out
>>> of it. So perhaps we might question if increased ambiguity is an overall
>>> good thing.
>>>
>>>
>>> I think you misunderstand the current Guidelines' goals. The Guidelines
>>> are not trying to reduce redundancy at declaration sites—they're trying to
>>> reduce redundancy at *call sites*. The idea is that, if the variable names
>>> for the method's target and parameters imply something about the types they
>>> contain, those names along with the prepositions will imply the purpose of
>>> each parameter, and therefore the call. The types are just a more formal
>>> version of that check.
>>>
>>> That's why the very first paragraph of the API Design Guidelines <
>>> https://swift.org/documentation/api-design-guidelines/> says:
>>>
>>> Clarity at the point of use is your most important goal. Entities such
>>> as methods and properties are declared only once but used repeatedly.
>>> Design APIs to make those uses clear and concise. When evaluating a design,
>>> reading a declaration is seldom sufficient; always examine a use case to
>>> make sure it looks clear in context.
>>>
>>>
>>> So the tradeoff is not between *declaration redundancy* and call site
>>> clarity—it is between *call site redundancy* and call site ambiguity.
>>> Because their parameters are unlabeled, most languages have severe call
>>> site ambiguity problems. Objective-C has a pretty serious call site
>>> redundancy problem. Swift's design is trying to hit the baby bear "just
>>> right" point.
>>>
>>> It is quite possible that, in some areas, we have swung too far back
>>> towards ambiguity. But I don't think `elementRemoved(atIndex:)` is going to
>>> fix that.
>>>
>>> However this removal of explicit contextual cues from the method
>>> signature harms readability, since now, the compiler will let people write
>>> code like:
>>>
>>> { return $0.fetch(withRecordID:$1) }
>>>
>>> Clearly, the onus is now on the developer not to use cryptic, short
>>> variable names or NO variable names. However, spend much time on GitHub or
>>> in CocoaPods and you will see an increasing number of codebases where
>>> that's exactly what they do, especially in closures.
>>>
>>>
>>> What I think you're missing with this example—and in fact with all of
>>> your closure-based examples—is that closures don't exist in isolation;
>>> they're in some larger context. (Otherwise, they won't compile.) For
>>> instance, the above closure might be in a line like:
>>>
>>> return zip(databases, recordIDs)
>>> .map { return $0.fetch(withRecordID:$1) }
>>>
>>> Read in the context of its line, the meanings of $0 and $1 are fairly
>>> clear.
>>>
>>> Another problem is that the compiler doesn't care if you write:
>>>
>>> { ambiguousName in
>>> let myRecordID = ambiguousName.fetch(withRecordID:myID)
>>> return myRecordID }
>>>
>>> This is highly problematic because someone reading this code will have
>>> no reason to expect the type of "myRecordID" not to be CKRecordID. (In
>>> fact, it's CKRecord.)
>>>
>>>
>>> Again, in the larger context, this line will end up generating a
>>> `[CKRecord]` array instead of a `[CKRecordID]` array, which is probably
>>> going to cause a type mismatch once you try to actually use the alleged
>>> record IDs. (But as I said earlier, I can see the case for using
>>> `fetchRecord(withID:)` or `fetchRecord(with:)` instead of
>>> `fetch(withRecordID:)`.)
>>>
>>> Ambiguous names can hide bugs in their ambiguity, but verbose names can
>>> also hide bugs in the sheer mass of code they generate. The difference is,
>>> developers can manage the ambiguity in their code by naming variables well,
>>> but they can't manage verbosity if verbose names are imposed on them.
>>>
>>> We also have examples like:
>>>
>>> { return $0.draw(with:$1) }
>>>
>>> What is $0? What is $1? This is a real Apple API, BTW.
>>>
>>>
>>> Again, the context of the closure would tell you, but part of the
>>> problem here is that they held onto an Objective-C preposition which was
>>> poorly chosen. If the line were `$0.draw(in:$1)`, you would know that
>>> `$1` specified an area of the screen and `$0` was something that could be
>>> drawn, which frankly is all you really *need* to know to understand what
>>> this line does.
>>>
>>> {array, key in
>>> let number = array.remove(at:key)
>>> return number }
>>>
>>> This will compile and run even though number will be a tuple key-value
>>> pair, array will be a dict, and key will be an index type! This may seem
>>> like a ridiculous example, but I have literally seen things like this.
>>>
>>>
>>> Where have you seen something like this? `array` would have to be passed
>>> `inout` for this to work at all.
>>>
>>> Nevertheless, how would more verbose names help with this problem? This
>>> is every bit as incorrect, and the compiler will still accept it:
>>>
>>> {array, key in
>>> let number = array.elementRemoved(atIndex:key)
>>> return number }
>>>
>>> Are you thinking that they'll notice that `atIndex` is not `atKey`?
>>> There is already a much stronger safeguard against that: `Dictionary.Index`
>>> and `Dictionary.Key` are different, totally incompatible types. Every
>>> mechanism I can think of to get a `Dictionary.Index` has "index" or
>>> "indices" in its name, so you could only make this mistake if you confused
>>> dictionary indices with dictionary keys, in which case `atIndex:` would not
>>> stand out to you either.
>>>
>>> Ultimately, unless the compiler actually understands identifiers, it's
>>> just not going to be able to catch mistakes like calling a dictionary an
>>> "array", or many of the other problems you describe here. But the type
>>> system can and often does flag these kinds of problems pretty close to the
>>> source.
>>>
>>> Orphaning method signatures by stripping useful return type and argument
>>> type information wouldn't be so bad if variables were all named
>>> descriptively, but that is a strangely optimistic hope for a language
>>> that's as paranoid about safety that it was specifically designed to
>>> prevent many categories of common mistakes.
>>>
>>>
>>> Personally, I think of Swift's approach to safety as similar to Reagan's
>>> "trust, but verify". Our naming conventions trust the programmer to write
>>> code with clear names; our picky type system verifies that the code is
>>> plausible. We don't force the programmer to explain herself to us until we
>>> notice that something doesn't seem right.
>>>
>>> The bottom line is, a language can't force you to write clear and
>>> correct code, but it has many tools it can use to encourage it. Swift
>>> chooses not to use the "heavily redundant names" tool because its cost to
>>> good code is too high. We instead rely more on other tools, like strong
>>> typing, value types, and definite initialization, to encourage high-quality
>>> code at a lower cost.
>>>
>>>
>>> More verbose rather than heavily redundant names tool, but what have we
>>> lost by being reliant on strongish static typing and value types? Would
>>> Cocoa/ UIKit be so nice to use if rewritten fully in idiomatic non @objc
>>> Swift (compared to working with UI on C++ platforms)? What would it tell us?
>>> Sorry for the rant... do not take static typing laying down j/k ;).
>>> (still quite in “love” with the opt-in  security that annotations and clang
>>> warnings bring in Objective-C rather than the opt-out freedom model some
>>> other languages have)
>>>
>>> --
>>> Brent Royal-Gordon
>>> Architechies
>>>
>>> _______________________________________________
>>> swift-evolution mailing list
>>> swift-evolution at swift.org
>>> https://lists.swift.org/mailman/listinfo/swift-evolution
>>>
>>> _______________________________________________
>>> swift-evolution mailing list
>>> swift-evolution at swift.org
>>> https://lists.swift.org/mailman/listinfo/swift-evolution
>>>
>>>
>>>
>>
>
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