You might want to consider it "intentionally misleading", but when I say
that they are a "real part of ES", I mean that when they are present under
certain circumstances, ES will take on behavior it wouldn't have if the
words had not been reserved. Does that mean those words are of any
practical use in the language? **NO**. However, the simple fact that the
behavior of the language changes as a result of their appearance makes them
a part of the language, albeit useless. However, all this has no logical
merit for my reason to use them. So believe what you will. I just wanted to
see how people would respond. That gives me a bit of useful information
about how to word my proposal as I make adjustments.
On Fri, Aug 3, 2018 at 10:32 PM Bob Myers <r...@gol.com> wrote:
> > `private`, `protected`, `class`, and a few other such keywords have all
> been part of ES since long be for the TC39 board got their hands on it.
> They hadn't been implemented, but they were all a very real part of ES.
>
> Whoa. Is that just misinformed or intentionally misleading? They have
> never been "part of ES" in any meaningful sense. It was not that they had
> not been implemented; it was that they had not even been defined. To say
> they are a "real part of ES" is a strange interpretation of the meaning of
> the word "real". The notion that we would choose features to work on based
> on some designation of certain keywords as reserved long ago, and that they
> are now "languishing", is odd. Why not focus on "implementing" enum, or
> final, or throws, or any other of the dozens of reserved words?
>
> Having said that, I think it is a valid general principle that as language
> designers we should be very reluctant to use magic characters. `**` is
> fine, of course, as is `=>`, or even `@` for decorators. Personally, I
> don't think the problem of access modifiers rises to the level of
> commonality and need for conciseness that would justify eating up another
> magic character. We also don't want JS to start looking like Perl or APL.
>
> Speaking as a self-appointed representative of Plain Old Programmers, I do
> feel a need for private fields, although it was probably starting to
> program more in TS that got me thinking that way. However, to me it feels
> odd to tie this directly to `class` syntax. Why can't I have a private
> field in a plain old object like `{a: 1}` (i.e., that would only be
> accessible via a method on that object? We already have properties which
> are enumerable and writable, for example, independent of the class
> mechanism. Why not have properties which are private in the same way?
>
> The problem,of course, is that even assuming the engines implemented the
> `private` property on descriptors, I obviously don't want to have to write
> `Object.create({}, {a: {value: 22, private: true})`. So the problem can be
> restated as trying to find some nice sugar for writing the above. You
> know, something like `{a<private>: 22}`. That's obviously a completely
> random syntax suggestion, just to show the idea. Perhaps we'd prefer to
> have the access modifiers be specifiable under program control as an object
> itself, to allow something like
>
> ```
> const PRIVATE = {private: true};
>
> const myObject = {a(<PRIVATE>: 2; }
> ```
>
> But what would the precise meaning of such as `private` descriptor
> property be? In operational terms, it could suffice to imagine (as a
> behavior, not as an implementation strategy) that objects would have a flag
> that would skip over private properties when doing property lookups. I
> think the right implementation is to have a private property look like it's
> not there at all when access is attempted from outside the object (in other
> words, is undefined), rather than some kind of `PrivatePropertyAccessError`.
>
> The above approach ought to be extensible to class notation:
>
> ```
> class Foo (
> bar<PRIVATE>(): { return 22; }
> }
> ```
>
> which would end up being something like
> `Object.defineProperty(Foo.prototype, "bar", {value() {return 22; },
> private: true})`.
>
> Or when classes get instance variables:
>
> ```
> class Foo {
> bar<PRIVATE> = 22;
> ```
>
> Was anything along these lines already brought up in this discussion?
>
> Bob
>
>
> On Sat, Aug 4, 2018 at 12:30 AM Ranando King <king...@gmail.com> wrote:
>
>> > It certainly doesn't look or feel like JS - it feels more like Java or
>> C#.
>>
>> `private`, `protected`, `class`, and a few other such keywords have all
>> been part of ES since long be for the TC39 board got their hands on it.
>> They hadn't been implemented, but they were all a very real part of ES. Now
>> that `class` has been implemented, it makes little sense to leave behind
>> the `private` and `protected` keywords when we are trying to implement
>> their functionality.
>>
>> > `private` looks like an identifier, and IMHO getters, setters, and
>> async functions suffer the same issue of the keyword seeming to blend in a
>> little with surrounding code.
>>
>> Have you ever thought that `var` or `let` look like identifiers? The
>> `private` and `protected` keywords serve the same role as `var` and `let`:
>> declaring a variable within a given scope or context. If you think there is
>> a good logical or rational reason to avoid using the keywords that have
>> been embedded in the language and left languishing, waiting for their
>> meaning to be implemented, then I'm willing to entertain that. If the
>> reason is based on mere feeling or emotion, well. I will only entertain
>> such arguments if my reason for doing things a certain way is equally
>> emotion based. Nothing I'm aware of in this proposal falls into that
>> category. I have logical reasons for every choice I've made.
>>
>> >> 2. `protected` on an object literal is next to useless. I've used
>> that kind of feature almost never.
>>
>> > And how would that be accessible?
>>
>> As you said, the vast majority of the time, this feature will go unused.
>> However, when it's needed, it would look something like this:
>>
>> ```js
>> var a = {
>> protected sharedData: 1,
>> increment() { ++this#.sharedData; },
>> print() { console.log(`sharedData = ${this#.sharedData}`); }
>> };
>>
>> var b = {
>> __proto__: a,
>> decrement() { --this#.sharedData; }
>> };
>> ```
>>
>> Setting `b.__proto__ = a` causes `b.[[PrivateValues]].__proto__ =
>> a.[[PrivateValues]]`, `b.[[DeclarationInfo]].__proto__ =
>> a.[[InheritanceInfo]]`, and `b.[[InheritanceInfo]].proto =
>> a.[[InheritanceInfo]]`. So it all just works.
>>
>> > I saw `obj#['key']`, which *strongly* suggests dynamic keys are
>> supported.
>>
>> Dynamic **_keys_** are supported. Dynamic **_properties_** are not!
>> Please don't conflate the two. Dynamic keys are calculated property names.
>> I am definitely supporting that. Dynamic properties refers to the ability
>> to add and remove properties from an object at any time. I am not
>> supporting that for private/protected members (unless someone can logically
>> convince me it's a good idea).
>>
>> On Fri, Aug 3, 2018 at 1:02 PM Isiah Meadows <isiahmead...@gmail.com>
>> wrote:
>>
>>> Inline
>>>
>>> On Fri, Aug 3, 2018, 11:12 Ranando King <king...@gmail.com> wrote:
>>>
>>>> > 1. It's *super incredibly boilerplatey* and verbose syntactically.
>>>>
>>>> I'm not sure what you mean by "boilerplatey". As for being verbose, I'm
>>>> just using the keywords everyone understands for this purpose. IMO, there's
>>>> no advantage in trying to find some shorthand to do the same thing just
>>>> because it saves a keystroke or two when it makes the code significantly
>>>> more difficult to understand.
>>>>
>>>
>>> But on the same token, it's verbose enough that I feel readability
>>> starts to suffer substantiallly. `private` looks like an identifier, and
>>> IMHO getters, setters, and async functions suffer the same issue of the
>>> keyword seeming to blend in a little with surrounding code. But those are
>>> more like decorating the function than the name.
>>>
>>> Based on reading the several meeting notes, I don't believe the keyword
>>> has been especially popular there, either. It certainly doesn't look or
>>> feel like JS - it feels more like Java or C#.
>>>
>>>
>>>> > 2. `protected` on an object literal is next to useless. I've used
>>>> that kind of feature almost never.
>>>>
>>>> I get where you're coming from with that. I don't see it being used
>>>> very often (kinda like `with`), but it has to be there. If someone wants to
>>>> use the facilities of `class` without the limitations of the keyword, and
>>>> the intent is to build vertical hierarchies, they'll need the "protected"
>>>> keyword on their prototype definition to share private data with descendant
>>>> factories.
>>>>
>>>
>>> And how would that be accessible? Because you can't expose it via the
>>> same way you do in classes without basically making them public (and
>>> several workarounds suffer similar issues).
>>>
>>> > I also find it odd you're supporting private dynamic properties.
>>>>
>>>> How'd you get to the idea that I'm supporting dynamic private
>>>> properties?
>>>>
>>>
>>> I saw `obj#['key']`, which *strongly* suggests dynamic keys are
>>> supported.
>>>
>>> > I actually think it's odd there is no attempt to implement dynamic
>>>> properties in the other "private properties" proposals.
>>>>
>>>
>>>> It's not that odd. There are issues around inheritance when a subclass
>>>> can remove the `protected` properties of its base. Further, exactly how do
>>>> you add a new `protected` property at runtime? Under both
>>>> proposal-class-fields and proposal-object-members, there is never any
>>>> direct access to the private container record, so use of
>>>> `Object.defineProperty` will never work. IMO, any attempt to implement
>>>> dynamic private properties in any sensible and consistent fashion would
>>>> require somehow exposing the private data record to the code. That's a
>>>> recipe for a private data leak. Not worth it.
>>>>
>>> _______________________________________________
>> es-discuss mailing list
>> es-discuss@mozilla.org
>> https://mail.mozilla.org/listinfo/es-discuss
>>
>
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