If both have the operator, the left side would be used (I thought I said
that, but I may have not). I'm thinking, instead, static methods should be
used. It would be more versatile.
```js
class Vec2 {
constructor(x, y) {
this.x = x
this.y = y
}
// `this` and `Vec2` are interchangeable
operator this + this(x, y) {
return new this(x.x + y.x, x.y + y.y)
}
operator this + #number(x, y) {
return new this(x.x + y, x.y + y)
}
operator this += this(x, y) {
x.x += y.x
x.y += y.y
}
operator this += #number(x, y) {
x.x += y
x.y += y
}
// #number += this -> x = x + this
operator -this(x) {
return new this(-x.x, -x.y)
}
// etc...
}
class Vec3 {
// ...
operator this + Vec2(x, y) {
return new this(x.x + y.x, x.y + y.y, x.z)
}
// etc...
}
```
A few notes on this:
1. If an operator doesn't reference `this` or the containing class at least
once, an early error is thrown.
2. To reference a primitive, you use the hash symbol + the typeof value.
The valid ones include `#string`, `#boolean`, `#number`, `#symbol`,
`#object`, `#function`, and `#undefined`. If value types with custom
`typeof` values are introduced, you have to reference the type directly.
3. All type references must be either `this`, identifiers, or member
expressions that do not reference `this`. It is an early error otherwise.
Member expressions are evaluated at class definition time as well, so that
can produce visible side effects if a proxy is referenced or a getter is
called.
4. The operators are checked via `instanceof`. This means, for those that
define operators, the behavior can become visible to previous code if the
other type specified has a static `Symbol.hasInstance` method.
The reason I provided the `this` alias is for anonymous classes, so you can
create anonymous objects. It's also helpful in case you have a longer class
name (possibly by convention) that you now don't have to type out.
On Thu, May 12, 2016, 01:17 Kevin Barabash <[email protected]> wrote:
> @Isiah: Great points. One potential edge case though:
>
> ```js
> class A {
> operator+ (other) { }
> }
>
> class B {
> operator+ (other) { }
> }
>
> const a = new A();
> const b = new B();
> const c = a + b;
> ```
>
> In the case where both the left and right side have `[[OpPlus]]` do we
> prefer the left side?
>
> > But, do we really need operator overloading? A method can be used
> instead, I think.
>
> @Dawid: Suppose I create a class to represent complex numbers that looks
> like this:
>
> ```js
> class Complex {
> constructor(re, im) {
> Object.assign({ }, { re, im });
> }
> add(other) {
> return new Complex(this.re + other.re, this.im + other.im);
> }
> ...
> }
> ```
>
> I might want to create instance of `Complex` with plain old numbers or I
> might want to use `BigNumber` instances.
> Without operator overloading this means that I would have add methods to
> `Number.prototype` or wrap each number
> in an object with methods. Neither of which are particular appealing.
>
>
>
> On Wed, May 11, 2016 at 1:28 AM, Isiah Meadows <[email protected]>
> wrote:
>
>> That's the current state of things. I think the main issue at hand is
>> ergonomics. Haskell, the MLs, and Swift solved it by allowing inline
>> functions and operators as functions (that wouldn't work in a dynamic
>> language). Scala solved it by magic methods for unary operations and the
>> fact nearly every character is a valid identifier for binary ones (JS can't
>> use that because of back compat issues). Lua, Ruby, Python, and Kotlin
>> solved it by using magic methods. C++ solved it with the `operator`
>> keyword.
>>
>> On Wed, May 11, 2016, 03:26 Dawid Szlachta <[email protected]>
>> wrote:
>>
>>> But, do we really need operator overloading? A method can be used
>>> instead, I think.
>>>
>>> 2016-05-11 8:53 GMT+02:00 Isiah Meadows <[email protected]>:
>>>
>>>> Efficiency and optimization. If you're stupid enough to want to violate
>>>> those priorities in a public API, it's your own fault. But if you want to
>>>> optimize updating a collection (i.e. zero allocation update for a
>>>> persistent map) or increment a vector by another without having to create
>>>> an intermediate vector, you'll want to implement the assignment operator as
>>>> well as the standard math operator.
>>>>
>>>> On Wed, May 11, 2016, 02:46 Jordan Harband <[email protected]> wrote:
>>>>
>>>>> Why would you ever want to violate the algebraic properties of
>>>>> operators, such that `a += b` wasn't exactly equivalent to `a = a + b`, `a
>>>>> *= b` not equivalent to `a = a * b`, etc? I'm quite confident that any
>>>>> proposal that allowed for that would get tons of pushback.
>>>>>
>>>>> On Tue, May 10, 2016 at 11:26 PM, Isiah Meadows <
>>>>> [email protected]> wrote:
>>>>>
>>>>>> 1. Yes, they would be inherited, but not on the prototype itself (it
>>>>>> would technically be parasitic). It would be modeled with internal slots,
>>>>>> so that the properties are themselves immutable and transparent, so the
>>>>>> only way to inherit would be via the class syntax or `Reflect.construct`.
>>>>>> Engines could model this similarly to prototypes internally, while still
>>>>>> appearing to conform to spec, since there's no other way to access the
>>>>>> function without explicit reference via a decorator. And if it's not
>>>>>> decorated, you can transparently fast path the calls automatically and
>>>>>> optimize the function at compile time for exactly the number of arguments
>>>>>> (any different is a syntax error, like with getters and setters).
>>>>>>
>>>>>> 2. I'm intentionally trying to avoid any semantics that would rely on
>>>>>> adding more values to the global scope. First, it's harder to optimize a
>>>>>> `hasOwnProperty` check. Second, when you allow properties to be
>>>>>> dynamically
>>>>>> added, you make it impossible to lower `foo + bar` to a single
>>>>>> instruction
>>>>>> if they're both numbers, because someone can change the Number prototype
>>>>>> to
>>>>>> have one of the operators on it, and now, the assumption, previously
>>>>>> prevalent, is now invalid. Third, we shouldn't need to add 15+ new
>>>>>> symbols
>>>>>> to accommodate a simple operation.
>>>>>>
>>>>>> 3. If it's pure syntax, you won't have the edge cases of `x += y`
>>>>>> having to desugar to `x = x[Symbol.assignPlus](y)` and so on. You just
>>>>>> look
>>>>>> for an `[[OpAssignPlus]]` on `x`, and if it exists, call it as
>>>>>> `x.[[OpAssignPlus]](y)`.
>>>>>> Else, you check for `[[OpPlus]]`, and set `x` to `x.[[OpPlus]](y)`. If
>>>>>> neither exists, you fall back to the old algorithm. This can be easily
>>>>>> optimized by the fact engines only need to check this if the value is an
>>>>>> object. Numbers and strings don't have this slot.
>>>>>>
>>>>>> Note: If the right side has an operator defined, but the left side
>>>>>> doesn't, and if the operator checked for isn't an assignment one, the
>>>>>> right
>>>>>> side's operator is checked and called. Or basically, beyond assignment,
>>>>>> the
>>>>>> mere existence of a slot takes precedence over no slot, to make
>>>>>> transitivity easier with primitives. To clarify, in the below case:
>>>>>>
>>>>>> ```js
>>>>>> class C {
>>>>>> constructor(x) { this.x = x }
>>>>>> operator +(x) {
>>>>>> if (x instanceof C) {
>>>>>> return this + x.x * 2
>>>>>> }
>>>>>> return this.x + x
>>>>>> }
>>>>>> }
>>>>>>
>>>>>> assert(new C(1) + 1 === 1 +1)
>>>>>> assert(1 + new C(1) === 1 + 1)
>>>>>> assert(new C(1) + new C(2) === 1 + 2*2)
>>>>>> assert(new C(2) + new C(1) === 2 + 1*2)
>>>>>> ```
>>>>>>
>>>>>> On Wed, May 11, 2016, 01:27 Kevin Barabash <[email protected]>
>>>>>> wrote:
>>>>>>
>>>>>>> > I would prefer syntax + internal slots, since you'll know at
>>>>>>> creation time whether the object has overloaded
>>>>>>> > operators. It's much simpler for the engine to figure out, and
>>>>>>> it's more performant because you only need to
>>>>>>> > check one thing instead of worrying about inheritance, own
>>>>>>> properties, etc.
>>>>>>>
>>>>>>> Will operators defined on a class work with instances of a subclass?
>>>>>>>
>>>>>>> > Could += be a special case? i.e.,
>>>>>>>
>>>>>>> For sure. We could define `Symbol.assignPlus`,
>>>>>>> `Symbol.assignTimes`, etc. with `u += v;` desugaring to `u =
>>>>>>> u[Symbol.assignPlus](v)`. The reason why we can't do something do
>>>>>>> `u[Symbol.assignPlus](v)` is that there's no way to define a method on
>>>>>>> Number, String, etc. that would reassign their value.
>>>>>>>
>>>>>>> > it appears to me that overloading an operator multiple times (e.
>>>>>>> g. unary/binary plus operator) might become
>>>>>>> > painful, assuming that the semantics follow the same variadic
>>>>>>> approach that regular functions do.
>>>>>>>
>>>>>>> Another pain point is handling cases where you want one class to
>>>>>>> interoperate with another. In one of the example above methods are
>>>>>>> defined
>>>>>>> that allow `Point`s and `Number`s to be added to each other. In order
>>>>>>> to
>>>>>>> maintain the commutativity of `+` we need to define `operator+` /
>>>>>>> `[Symbol.add]` methods on both `Point` and `Number`. One potential
>>>>>>> solution to this problem is create `Symbol.plusRight`,
>>>>>>> `Symbol.timesRight`
>>>>>>> for all of the commutative/symmetric operators.
>>>>>>>
>>>>>>> I feel like this ends up making things more complex because there
>>>>>>> are more methods to implement and the methods have to be more complex
>>>>>>> b/c
>>>>>>> they have to do type checking when overloaded.
>>>>>>>
>>>>>>> Maybe `operator+` could work like the `@operator` decorator by
>>>>>>> calling `Function.defineOperator` behind the scenes. In this situation,
>>>>>>> instead of methods being added to classes, the `Function` object has
>>>>>>> well-defined methods that look up the correct function to call based on
>>>>>>> the
>>>>>>> argument types. `u + v` desugars to `Function[Symbol.plus](u, v)`.
>>>>>>> This
>>>>>>> is definitely slower than internal slots, but if we're doing runtime
>>>>>>> type
>>>>>>> checking in the method we may as well have it be automatic. My hope is
>>>>>>> to
>>>>>>> eventually use static typing (flow b/c I'm using babel) to remove the
>>>>>>> lookup cost.
>>>>>>>
>>>>>>>
>>>>>>> On Tue, May 10, 2016 at 7:07 PM, Isiah Meadows <
>>>>>>> [email protected]> wrote:
>>>>>>>
>>>>>>>> You're correct in that the operator doesn't do any type checking
>>>>>>>> (it dispatches from its first argument, but that's just traditional
>>>>>>>> OO).
>>>>>>>>
>>>>>>>> On Tue, May 10, 2016, 20:28 kdex <[email protected]> wrote:
>>>>>>>>
>>>>>>>>> @Isiah: Comparing your syntax proposal to
>>>>>>>>> `Function.defineOperator`, it appears to me that
>>>>>>>>> overloading an operator multiple times (e. g. unary/binary plus
>>>>>>>>> operator) might become painful,
>>>>>>>>> assuming that the semantics follow the same variadic approach that
>>>>>>>>> regular functions do.
>>>>>>>>>
>>>>>>>>> That is, of course, unless you intend to handle all operator
>>>>>>>>> overloads in a single `operator +(...args) {}`
>>>>>>>>> definition. But then again, something like
>>>>>>>>> `Function.defineOperator` seems cleaner and suggests implicit
>>>>>>>>> (optional?) type checks with its second argument.
>>>>>>>>>
>>>>>>>>> On Dienstag, 10. Mai 2016 15:25:32 CEST Isiah Meadows wrote:
>>>>>>>>> > Here's my thought, if we go with syntax.
>>>>>>>>> >
>>>>>>>>> > ```js
>>>>>>>>> > class Point {
>>>>>>>>> > // constructor, etc.
>>>>>>>>> >
>>>>>>>>> > operator +(other) {
>>>>>>>>> > assert(other instanceof Point)
>>>>>>>>> > return new Point(
>>>>>>>>> > this.x + other.x,
>>>>>>>>> > this.y + other.y)
>>>>>>>>> > }
>>>>>>>>> >
>>>>>>>>> > operator +=(other) {
>>>>>>>>> > assert(other instanceof Point)
>>>>>>>>> > this.x += other.x
>>>>>>>>> > this.y += other.y
>>>>>>>>> > }
>>>>>>>>> > }
>>>>>>>>> > ```
>>>>>>>>> >
>>>>>>>>> > On Tue, May 10, 2016, 11:16 Brian Barnes <[email protected]>
>>>>>>>>> wrote:
>>>>>>>>> >
>>>>>>>>> > > A note on this from somebody who's entire existence seems
>>>>>>>>> dedicated to
>>>>>>>>> > > stopping as much stuff as possible from getting GC'd, the
>>>>>>>>> example below:
>>>>>>>>> > >
>>>>>>>>> > > >const u = new Point(5, 10);
>>>>>>>>> > > >const v = new Point(1, -2);
>>>>>>>>> > > >
>>>>>>>>> > > >const w = u + v; // desugars to u[Symbol.add](v)
>>>>>>>>> > > >console.log(w); // { x: 6, y: 8 };
>>>>>>>>> > >
>>>>>>>>> > > Could += be a special case? i.e.,
>>>>>>>>> > >
>>>>>>>>> > > u+=v;
>>>>>>>>> > >
>>>>>>>>> > > would call:
>>>>>>>>> > >
>>>>>>>>> > > Class Point { ... other stuff ...
>>>>>>>>> > > [whatever the syntax is](pt)
>>>>>>>>> > > {
>>>>>>>>> > > this.x+=pt.x;
>>>>>>>>> > > this.y+=pt.y;
>>>>>>>>> > > }
>>>>>>>>> > > }
>>>>>>>>> > >
>>>>>>>>> > > instead of desugaring to:
>>>>>>>>> > >
>>>>>>>>> > > u=u+v; // which would cause the creation of an object
>>>>>>>>> and
>>>>>>>>> > > // leave the other to be collected
>>>>>>>>> > >
>>>>>>>>> > > For all I know, += might be doing such anyway in some engines,
>>>>>>>>> but for
>>>>>>>>> > > my stuff which is a lot of 3D math that could be a performance
>>>>>>>>> killer.
>>>>>>>>> > > It would be nice to be able to just add points and such, as
>>>>>>>>> long as the
>>>>>>>>> > > overhead is negligible.
>>>>>>>>> > >
>>>>>>>>> > > [>] Brian
>>>>>>>>> > >
>>>>>>>>> > > On 5/10/2016 10:52 AM, Isiah Meadows wrote:
>>>>>>>>> > > > I would prefer syntax + internal slots, since you'll know at
>>>>>>>>> creation
>>>>>>>>> > > > time whether the object has overloaded operators. It's much
>>>>>>>>> simpler for
>>>>>>>>> > > > the engine to figure out, and it's more performant because
>>>>>>>>> you only need
>>>>>>>>> > > > to check one thing instead of worrying about inheritance, own
>>>>>>>>> > > > properties, etc.
>>>>>>>>> > > >
>>>>>>>>> > > > Also, it would be IMHO easier to read than a symbol (the
>>>>>>>>> computed
>>>>>>>>> > > > property syntax is ugly IMO). Using a different concept than
>>>>>>>>> symbols
>>>>>>>>> > > > would also fit better with value types whenever any of those
>>>>>>>>> proposals
>>>>>>>>> > > > make it into the language (either the struct or special
>>>>>>>>> syntax).
>>>>>>>>> > > >
>>>>>>>>> > > >
>>>>>>>>> > > > On Tue, May 10, 2016, 04:03 G. Kay Lee
>>>>>>>>> > > > <[email protected]
>>>>>>>>> > > > <mailto:balancetraveller%[email protected]>> wrote:
>>>>>>>>> > > >
>>>>>>>>> > > > Yes, I think exposing operators through well-known
>>>>>>>>> symbols is an
>>>>>>>>> > > > interesting idea worthy of more exploration because it's
>>>>>>>>> precisely
>>>>>>>>> > > > the purpose of well-known symbols to expose and allow
>>>>>>>>> manipulation
>>>>>>>>> > > > to previously inaccessible internal language behaviors.
>>>>>>>>> > > >
>>>>>>>>> > > > On Tue, May 10, 2016 at 1:59 PM, Kevin Barabash
>>>>>>>>> > > > <[email protected] <mailto:[email protected]>>
>>>>>>>>> wrote:
>>>>>>>>> > > >
>>>>>>>>> > > > > And remember that decorators are essentially just
>>>>>>>>> a syntax to
>>>>>>>>> > > > apply functions to objects/classes at design time,
>>>>>>>>> so what
>>>>>>>>> > > > you're proposing is essentially some new global
>>>>>>>>> function, which
>>>>>>>>> > > > is going against the current trend and effort to
>>>>>>>>> better
>>>>>>>>> > > > modularize/namespace all these utility
>>>>>>>>> functions/methods.
>>>>>>>>> > > >
>>>>>>>>> > > > That's a really good point.
>>>>>>>>> > > >
>>>>>>>>> > > > > It has been mentioned and discussed in numerous
>>>>>>>>> places over the
>>>>>>>>> > > > years, you can find more info on this with some
>>>>>>>>> casual googling.
>>>>>>>>> > > > For example:
>>>>>>>>> https://news.ycombinator.com/item?id=2983420
>>>>>>>>> > > >
>>>>>>>>> > > > Thanks for the link. I played around with sweet.js
>>>>>>>>> a bit over
>>>>>>>>> > > > the weekend. Using macros should work if we went
>>>>>>>>> with Python
>>>>>>>>> > > > style operator overloading. Instead of defining
>>>>>>>>> methods like
>>>>>>>>> > > > _ADD_, _SUB_ etc. we could create some well-known
>>>>>>>>> symbols, maybe
>>>>>>>>> > > > Symbol.plus, Symbol.times, etc.
>>>>>>>>> > > >
>>>>>>>>> > > > ```
>>>>>>>>> > > > class Point {
>>>>>>>>> > > > constructor(x, y) {
>>>>>>>>> > > > Object.assign(this, {x, y});
>>>>>>>>> > > > }
>>>>>>>>> > > >
>>>>>>>>> > > > [Symbol.add](other) {
>>>>>>>>> > > > return new Point(this.x + other.x, this.y +
>>>>>>>>> other.y);
>>>>>>>>> > > > }
>>>>>>>>> > > > }
>>>>>>>>> > > >
>>>>>>>>> > > > const u = new Point(5, 10);
>>>>>>>>> > > > const v = new Point(1, -2);
>>>>>>>>> > > >
>>>>>>>>> > > > const w = u + v; // desugars to u[Symbol.add](v)
>>>>>>>>> > > > console.log(w); // { x: 6, y: 8 };
>>>>>>>>> > > > ```
>>>>>>>>> > > >
>>>>>>>>> > > > This would require default implementations to be
>>>>>>>>> defined on
>>>>>>>>> > > > Object.prototype for Symbol.plus, Symbol.times, etc.
>>>>>>>>> > > >
>>>>>>>>> > > >
>>>>>>>>> > > > On Sun, May 8, 2016 at 10:38 PM, G. Kay Lee
>>>>>>>>> > > > <[email protected]
>>>>>>>>> > > > <mailto:[email protected]>>
>>>>>>>>> wrote:
>>>>>>>>> > > >
>>>>>>>>> > > > > Why not? The standard defines well-known
>>>>>>>>> symbols. Maybe
>>>>>>>>> > > `@operator` could be a well known decorator (assuming
>>>>>>>>> decorators get
>>>>>>>>> > > approved).
>>>>>>>>> > > >
>>>>>>>>> > > > Well... you make something into the standard
>>>>>>>>> with proposals,
>>>>>>>>> > > > not why-nots, so in order to make that happen
>>>>>>>>> you need to
>>>>>>>>> > > > draft another proposal for well-known
>>>>>>>>> decorators. And
>>>>>>>>> > > > remember that decorators are essentially just a
>>>>>>>>> syntax to
>>>>>>>>> > > > apply functions to objects/classes at design
>>>>>>>>> time, so what
>>>>>>>>> > > > you're proposing is essentially some new global
>>>>>>>>> function,
>>>>>>>>> > > > which is going against the current trend and
>>>>>>>>> effort to
>>>>>>>>> > > > better modularize/namespace all these utility
>>>>>>>>> > > > functions/methods. And maybe a new mechanism
>>>>>>>>> could be
>>>>>>>>> > > > drafted for these new well-known decorators, so
>>>>>>>>> that we can
>>>>>>>>> > > > hide these new functions somewhere... but by now
>>>>>>>>> I hope it's
>>>>>>>>> > > > becoming clear that it's introducing way too
>>>>>>>>> much new
>>>>>>>>> > > > surface area for the language in exchange for
>>>>>>>>> one small
>>>>>>>>> > > feature.
>>>>>>>>> > > >
>>>>>>>>> > > > > I haven't seen any proposals for macros, could
>>>>>>>>> you post a
>>>>>>>>> > > link?
>>>>>>>>> > > >
>>>>>>>>> > > > It has been mentioned and discussed in numerous
>>>>>>>>> places over
>>>>>>>>> > > > the years, you can find more info on this with
>>>>>>>>> some casual
>>>>>>>>> > > > googling. For example:
>>>>>>>>> > > > https://news.ycombinator.com/item?id=2983420
>>>>>>>>> > > >
>>>>>>>>> > > >
>>>>>>>>> > > >
>>>>>>>>> > > > On Sun, May 8, 2016 at 2:51 PM, Kevin Barabash
>>>>>>>>> > > > <[email protected] <mailto:
>>>>>>>>> [email protected]>>
>>>>>>>>> > > wrote:
>>>>>>>>> > > >
>>>>>>>>> > > > I should update the demo code to show the
>>>>>>>>> `@operator`
>>>>>>>>> > > > decorator in addition to
>>>>>>>>> `Function.defineOperator`.
>>>>>>>>> > > >
>>>>>>>>> > > > Initially I started out with just the
>>>>>>>>> `@operator`
>>>>>>>>> > > > decorator, but that meant that each class
>>>>>>>>> would have to
>>>>>>>>> > > > have knowledge of each of the classes it
>>>>>>>>> might want to
>>>>>>>>> > > > interact with before hand. Having a separate
>>>>>>>>> > > > `defineOperator` function avoids this
>>>>>>>>> situation.
>>>>>>>>> > > >
>>>>>>>>> > > > It means that prototype style classes must
>>>>>>>>> be converted
>>>>>>>>> > > > to the new class syntax before operator
>>>>>>>>> overloading
>>>>>>>>> > > > could be used. Lastly, there may be some
>>>>>>>>> cases where it
>>>>>>>>> > > > makes sense to overload operators with
>>>>>>>>> existing 3rd
>>>>>>>>> > > > party code or built-in classes, e.g. adding
>>>>>>>>> set
>>>>>>>>> > > > operations to Set using operator overloading.
>>>>>>>>> > > >
>>>>>>>>> > > > > It's also apparent that the `@operator
>>>>>>>>> decorator` part
>>>>>>>>> > > > of the proposal is an effort trying to
>>>>>>>>> address this
>>>>>>>>> > > > issue, but it really is not the
>>>>>>>>> responsibility of the
>>>>>>>>> > > > standard to try to define such a thing.
>>>>>>>>> > > >
>>>>>>>>> > > > Why not? The standard defines well-known
>>>>>>>>> symbols.
>>>>>>>>> > > > Maybe `@operator` could be a well known
>>>>>>>>> decorator
>>>>>>>>> > > > (assuming decorators get approved).
>>>>>>>>> > > >
>>>>>>>>> > > > Slide 15
>>>>>>>>> > > > from
>>>>>>>>> http://www.slideshare.net/BrendanEich/js-resp shows
>>>>>>>>> > > > syntax for defining operators in value types
>>>>>>>>> which could
>>>>>>>>> > > > be adapted as follows for regular classes:
>>>>>>>>> > > >
>>>>>>>>> > > > ```
>>>>>>>>> > > > class Point {
>>>>>>>>> > > > constructor(x, y) {
>>>>>>>>> > > > this.x = +x;
>>>>>>>>> > > > this.y = +y;
>>>>>>>>> > > > }
>>>>>>>>> > > > Point + Number (a, b) {
>>>>>>>>> > > > return new Point(a.x + b, a.y + b);
>>>>>>>>> > > > }
>>>>>>>>> > > > Number + Point (a, b) {
>>>>>>>>> > > > return new Point(a + b.x, a + b.y);
>>>>>>>>> > > > }
>>>>>>>>> > > > Point + Point (a, b) {
>>>>>>>>> > > > return new Point(a.x + b.x, a.y +
>>>>>>>>> b.y);
>>>>>>>>> > > > }
>>>>>>>>> > > > }
>>>>>>>>> > > > ```
>>>>>>>>> > > >
>>>>>>>>> > > > Having to define `+` twice for `Point +
>>>>>>>>> Number` and
>>>>>>>>> > > > `Number + Point` seems like busy work, but
>>>>>>>>> maybe it's
>>>>>>>>> > > > better to be explicit. What are you
>>>>>>>>> thoughts about this
>>>>>>>>> > > > syntax?
>>>>>>>>> > > >
>>>>>>>>> > > > > Another thing is that, IMHO, currently
>>>>>>>>> there are too
>>>>>>>>> > > > much quirks/conventions in the proposal that
>>>>>>>>> feel
>>>>>>>>> > > > non-evident and non-flexible which is
>>>>>>>>> destined to trip
>>>>>>>>> > > > people over from time to time. It would be
>>>>>>>>> great to make
>>>>>>>>> > > > a proposal that's simple and don't include
>>>>>>>>> too much
>>>>>>>>> > > > assumptions.
>>>>>>>>> > > >
>>>>>>>>> > > > Could you elaborator what quirks/conventions
>>>>>>>>> might trip
>>>>>>>>> > > > people up?
>>>>>>>>> > > >
>>>>>>>>> > > > > Finally, I'm not sure about the current
>>>>>>>>> status of
>>>>>>>>> > > > macros, but last I heard of it, they say
>>>>>>>>> it's going to
>>>>>>>>> > > > make its way into the standard pretty soon
>>>>>>>>> (TM), and
>>>>>>>>> > > > macros can do much of the things overloading
>>>>>>>>> could, and
>>>>>>>>> > > > much more.
>>>>>>>>> > > >
>>>>>>>>> > > > I haven't seen any proposals for macros,
>>>>>>>>> could you post
>>>>>>>>> > > > a link?
>>>>>>>>> > > >
>>>>>>>>> > > >
>>>>>>>>> > > >
>>>>>>>>> > > >
>>>>>>>>> > > >
>>>>>>>>> > > >
>>>>>>>>> > > >
>>>>>>>>> > > > On Sat, May 7, 2016 at 9:55 PM, G. Kay Lee
>>>>>>>>> > > > <[email protected]
>>>>>>>>> > > > <mailto:
>>>>>>>>> [email protected]>> wrote:
>>>>>>>>> > > >
>>>>>>>>> > > > I'd say it's way too early to ask for a
>>>>>>>>> champion on
>>>>>>>>> > > > this because just a quick skimming
>>>>>>>>> revealed a lot of
>>>>>>>>> > > > places that didn't add up. For example,
>>>>>>>>> the proposal
>>>>>>>>> > > > suggested that overloading is primarily
>>>>>>>>> targeted at
>>>>>>>>> > > > making it easier to work with
>>>>>>>>> user-defined classes,
>>>>>>>>> > > > but curiously a
>>>>>>>>> `Function.defineOperator()` method
>>>>>>>>> > > > is proposed instead of some syntax that
>>>>>>>>> feels more
>>>>>>>>> > > > tightly integrated with the class
>>>>>>>>> definition syntax.
>>>>>>>>> > > >
>>>>>>>>> > > > ```
>>>>>>>>> > > >
>>>>>>>>> > > > class Point {
>>>>>>>>> > > > constructor(x, y) {
>>>>>>>>> > > > Object.assign(this, { x, y });
>>>>>>>>> > > > }
>>>>>>>>> > > >
>>>>>>>>> > > > toString() {
>>>>>>>>> > > > return `(${this.x}, ${this.y})`;
>>>>>>>>> > > > }
>>>>>>>>> > > > }
>>>>>>>>> > > >
>>>>>>>>> > > > Function.defineOperator('+', [Point,
>>>>>>>>> Point], (a, b)
>>>>>>>>> > > => new Point(a.x + b.x, a.y + b.y));
>>>>>>>>> > > >
>>>>>>>>> > > > ```
>>>>>>>>> > > >
>>>>>>>>> > > > The demo code made this flaw evident -
>>>>>>>>> it looks like
>>>>>>>>> > > > a giant step backward to define an
>>>>>>>>> instance method
>>>>>>>>> > > > like this, don't you agree?
>>>>>>>>> > > >
>>>>>>>>> > > > It's also apparent that the `@operator
>>>>>>>>> decorator`
>>>>>>>>> > > > part of the proposal is an effort trying
>>>>>>>>> to address
>>>>>>>>> > > > this issue, but it really is not the
>>>>>>>>> responsibility
>>>>>>>>> > > > of the standard to try to define such a
>>>>>>>>> thing.
>>>>>>>>> > > >
>>>>>>>>> > > > What I'd suggest is that perhaps you
>>>>>>>>> should rethink
>>>>>>>>> > > > your proposed syntax and redesign it to
>>>>>>>>> become an
>>>>>>>>> > > > extension of the ES6 class definition
>>>>>>>>> syntax.
>>>>>>>>> > > >
>>>>>>>>> > > > Another thing is that, IMHO, currently
>>>>>>>>> there are too
>>>>>>>>> > > > much quirks/conventions in the proposal
>>>>>>>>> that feel
>>>>>>>>> > > > non-evident and non-flexible which is
>>>>>>>>> destined to
>>>>>>>>> > > > trip people over from time to time. It
>>>>>>>>> would be
>>>>>>>>> > > > great to make a proposal that's simple
>>>>>>>>> and don't
>>>>>>>>> > > > include too much assumptions.
>>>>>>>>> > > >
>>>>>>>>> > > > Finally, I'm not sure about the current
>>>>>>>>> status of
>>>>>>>>> > > > macros, but last I heard of it, they say
>>>>>>>>> it's going
>>>>>>>>> > > > to make its way into the standard pretty
>>>>>>>>> soon (TM),
>>>>>>>>> > > > and macros can do much of the things
>>>>>>>>> overloading
>>>>>>>>> > > > could, and much more.
>>>>>>>>> > > >
>>>>>>>>> > > > On Sun, May 8, 2016 at 8:51 AM, Kevin
>>>>>>>>> Barabash
>>>>>>>>> > > > <[email protected]
>>>>>>>>> > > > <mailto:[email protected]>> wrote:
>>>>>>>>> > > >
>>>>>>>>> > > > I forgot to mention in my last email
>>>>>>>>> that I'm
>>>>>>>>> > > > looking for a champion for this
>>>>>>>>> proposal.
>>>>>>>>> > > >
>>>>>>>>> > > > On Sat, May 7, 2016 at 5:24 PM,
>>>>>>>>> Kevin Barabash
>>>>>>>>> > > > <[email protected]
>>>>>>>>> > > > <mailto:[email protected]>>
>>>>>>>>> wrote:
>>>>>>>>> > > >
>>>>>>>>> > > > Hi everyone,
>>>>>>>>> > > >
>>>>>>>>> > > > I've been working on
>>>>>>>>> implementing operator
>>>>>>>>> > > > overloading and would like to
>>>>>>>>> submit a
>>>>>>>>> > > proposal.
>>>>>>>>> > > >
>>>>>>>>> > > > I think operator overloading
>>>>>>>>> would be a
>>>>>>>>> > > > useful addition to the
>>>>>>>>> language. In
>>>>>>>>> > > > particular I think it would be
>>>>>>>>> useful for
>>>>>>>>> > > > defining operations on common
>>>>>>>>> mathematical
>>>>>>>>> > > > object types such as complex
>>>>>>>>> numbers,
>>>>>>>>> > > > vectors, matrices, and sets.
>>>>>>>>> > > >
>>>>>>>>> > > > I've create a working prototype
>>>>>>>>> that
>>>>>>>>> > > > consists of:
>>>>>>>>> > > >
>>>>>>>>> > > > * babel plugin that rewrites
>>>>>>>>> operators as
>>>>>>>>> > > > function calls
>>>>>>>>> > > > * a polyfill which defines
>>>>>>>>> these functions
>>>>>>>>> > > > and which call the correct
>>>>>>>>> > > > argument-specific function
>>>>>>>>> based on the
>>>>>>>>> > > > arguments' prototypes
>>>>>>>>> > > > * Function.defineOperator
>>>>>>>>> which can be
>>>>>>>>> > > > used to define which
>>>>>>>>> function an
>>>>>>>>> > > > operator should use for the
>>>>>>>>> specified
>>>>>>>>> > > types
>>>>>>>>> > > > * "use overloading" directive
>>>>>>>>> which allows
>>>>>>>>> > > > users to opt-in
>>>>>>>>> > > >
>>>>>>>>> > > > More details can be found
>>>>>>>>> > > > at
>>>>>>>>> > > https://github.com/kevinbarabash/operator-overloading.
>>>>>>>>> > > > The babel plugin can be found
>>>>>>>>> > > > at
>>>>>>>>> > >
>>>>>>>>> https://github.com/kevinbarabash/babel-plugin-operator-overloading
>>>>>>>>> .
>>>>>>>>> > > > I also have a demo project at
>>>>>>>>> > > >
>>>>>>>>> > > https://github.com/kevinbarabash/operator-overloading-demo.
>>>>>>>>> > > >
>>>>>>>>> > > > The design was inspired by some
>>>>>>>>> of the
>>>>>>>>> > > > slides from
>>>>>>>>> > > >
>>>>>>>>> > > http://www.slideshare.net/BrendanEich/js-resp.
>>>>>>>>> > > >
>>>>>>>>> > > > – Kevin
>>>>>>>>> > > >
>>>>>>>>> > > >
>>>>>>>>> > > >
>>>>>>>>> > > >
>>>>>>>>> > > >
>>>>>>>>> _______________________________________________
>>>>>>>>> > > > es-discuss mailing list
>>>>>>>>> > > > [email protected]
>>>>>>>>> > > > <mailto:[email protected]>
>>>>>>>>> > > >
>>>>>>>>> https://mail.mozilla.org/listinfo/es-discuss
>>>>>>>>> > > >
>>>>>>>>> > > >
>>>>>>>>> > > >
>>>>>>>>> > > >
>>>>>>>>> _______________________________________________
>>>>>>>>> > > > es-discuss mailing list
>>>>>>>>> > > > [email protected] <mailto:
>>>>>>>>> > > [email protected]>
>>>>>>>>> > > >
>>>>>>>>> https://mail.mozilla.org/listinfo/es-discuss
>>>>>>>>> > > >
>>>>>>>>> > > >
>>>>>>>>> > > >
>>>>>>>>> > > >
>>>>>>>>> _______________________________________________
>>>>>>>>> > > > es-discuss mailing list
>>>>>>>>> > > > [email protected] <mailto:
>>>>>>>>> [email protected]>
>>>>>>>>> > > > https://mail.mozilla.org/listinfo/es-discuss
>>>>>>>>> > > >
>>>>>>>>> > > >
>>>>>>>>> > > >
>>>>>>>>> > > > _______________________________________________
>>>>>>>>> > > > es-discuss mailing list
>>>>>>>>> > > > [email protected] <mailto:
>>>>>>>>> [email protected]>
>>>>>>>>> > > > https://mail.mozilla.org/listinfo/es-discuss
>>>>>>>>> > > >
>>>>>>>>> > > >
>>>>>>>>> > > >
>>>>>>>>> > > > _______________________________________________
>>>>>>>>> > > > es-discuss mailing list
>>>>>>>>> > > > [email protected] <mailto:
>>>>>>>>> [email protected]>
>>>>>>>>> > > > https://mail.mozilla.org/listinfo/es-discuss
>>>>>>>>> > > >
>>>>>>>>> > > >
>>>>>>>>> > > > _______________________________________________
>>>>>>>>> > > > es-discuss mailing list
>>>>>>>>> > > > [email protected] <mailto:[email protected]>
>>>>>>>>> > > > https://mail.mozilla.org/listinfo/es-discuss
>>>>>>>>> > > >
>>>>>>>>> > > >
>>>>>>>>> > > >
>>>>>>>>> > > > _______________________________________________
>>>>>>>>> > > > es-discuss mailing list
>>>>>>>>> > > > [email protected]
>>>>>>>>> > > > https://mail.mozilla.org/listinfo/es-discuss
>>>>>>>>> > > >
>>>>>>>>> > > _______________________________________________
>>>>>>>>> > > es-discuss mailing list
>>>>>>>>> > > [email protected]
>>>>>>>>> > > https://mail.mozilla.org/listinfo/es-discuss
>>>>>>>>> > >
>>>>>>>>> >
>>>>>>>>>
>>>>>>>>
>>>>>>>> _______________________________________________
>>>>>>>> es-discuss mailing list
>>>>>>>> [email protected]
>>>>>>>> https://mail.mozilla.org/listinfo/es-discuss
>>>>>>>>
>>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> es-discuss mailing list
>>>>>>> [email protected]
>>>>>>> https://mail.mozilla.org/listinfo/es-discuss
>>>>>>>
>>>>>>
>>>>>> _______________________________________________
>>>>>> es-discuss mailing list
>>>>>> [email protected]
>>>>>> https://mail.mozilla.org/listinfo/es-discuss
>>>>>>
>>>>>>
>>>>>
>>>> _______________________________________________
>>>> es-discuss mailing list
>>>> [email protected]
>>>> https://mail.mozilla.org/listinfo/es-discuss
>>>>
>>>>
>>>
>> _______________________________________________
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