cyril.auburtin at gmail.com (2016-08-11T11:06:14.896Z)
Just bumping this up
Calling `foo(1)` where foo is defined with 3 arguments, lets the 2 others
undefined, this behavior is already a bit magic and similar to the behavior
of an array, so I still think foo(a,,b,,,c) should be like
foo(...[a,,b,,,c])
Other example:
```
var m=new Map([[1], [2,], [3,7]]) // Map {1 => undefined, 2 => undefined, 3 => 7} // here commas fantasies are allowed in arrays
m.set(3) // Map {1 => undefined, 2 => undefined, 3 => undefined} // setting implicitely value as undefined
m.set(3, ) // not allowed, which should be m.set(...[3,]) or m.set(3, undefined)
```
and again, it would help for callbacks too, `something( ( , , thirdArg) =>
{} )`
I saw this https://jeffmo.github.io/es-trailing-function-commas/, it seems
like a sub-casecyril.auburtin at gmail.com (2016-08-08T10:43:06.828Z)
Just bumping this up
Calling `foo(1)` where foo is defined with 3 arguments, lets the 2 others
undefined, this behavior is already a bit magic and similar to the behavior
of an array, so I still think foo(a,,b,,,c) should be like
foo(...[a,,b,,,c])
Other example:
```
var m=new Map([[1], [2,], [3,7]]) // Map {1 => undefined, 2 => undefined, 3 => 7} // here commas fantasies are allowed in arrays
m.set(3) // Map {1 => undefined, 2 => undefined, 3 => undefined} // setting implicitely value as undefined
m.set(3, ) // not allowed, which should be m.set(...[3,]) or m.set(3, undefined)
```
and again, it would help for callbacks too, `something( ( , , thirdArg) =>
{} )`
I saw this https://jeffmo.github.io/es-trailing-function-commas/, it seems
like a sub-case
2016-05-29 23:07 GMT+02:00 Renki Ivanko <fatalis.erratum at gmail.com>:cyril.auburtin at gmail.com (2016-08-08T10:36:24.033Z)
Just bumping this up
Calling `foo(1)` where foo is defined with 3 arguments, lets the 2 others
undefined, this behavior is already a bit magic and similar to the behavior
of an array, so I still think foo(a,,b,,,c) should be like
foo(...[a,,b,,,c])
Other example:
```
var m=new Map([[1], [2,], [3,7]]) // Map {1 => undefined, 2 => undefined, 3 => 7} // here commas fantasies are allowed in arrays
m.set(3) // Map {1 => undefined, 2 => undefined, 3 => undefined} // setting implicitely value as undefined
m.set(3, ) // not allowed, which should be m.set(...[3,])
```
and again, it would help for callbacks too, `something( ( , , thirdArg) =>
{} )`
I saw this https://jeffmo.github.io/es-trailing-function-commas/, it seems
like a sub-case
2016-05-29 23:07 GMT+02:00 Renki Ivanko <fatalis.erratum at gmail.com>:
Just bumping this up Calling `foo(1)` where foo is defined with 3 arguments, lets the 2 others undefined, this behavior is already a bit magic and similar to the behavior of an array, so I still think foo(a,,b,,,c) should be like foo(...[a,,b,,,c]) Other example: ``` var m=new Map([[1], [2,], [3,7]]) // Map {1 => undefined, 2 => undefined, 3 => 7} // here commas fantasies are allowed in arrays m.set(3) // Map {1 => undefined, 2 => undefined, 3 => undefined} // setting implicitely value as undefined m.set(3, ) // not allowed, which should be m.set(...[3,]) ``` and again, it would help for callbacks too, `something( ( , , thirdArg) => {} )` I saw this https://jeffmo.github.io/es-trailing-function-commas/, it seems like a sub-case 2016-05-29 23:07 GMT+02:00 Renki Ivanko <fatalis.erratum at gmail.com>: > One more similarity is that both function parameters and destructuring > allow default values: (foo = 1) vs [foo = 1]. > > > > On Sun, May 29, 2016 at 11:56 PM, Cyril Auburtin <cyril.auburtin at gmail.com > > wrote: > >> Since functions arguments is an array under the hood, they could 'more >> behave the same' >> >> Both function arguments and arrays accept spreading: *[1, 2, ...args] * >> and *fn(1, 2, ...args)* >> >> a function definition like *(,i) => {}*, would be the equivalent of *var >> [,i] = arguments* >> >> an invocation *fn(,,i)* would be the equivalent of *[,,i]* >> >> It's possible with *(...[,i]) => {}, (_,i)=>{} *like Renki said, but >> slightly less simply >> >> Are there possible issues with that 'extension' of function syntax? >> >> >> 2016-05-29 21:32 GMT+02:00 Renki Ivanko <fatalis.erratum at gmail.com>: >> >>> You could stop with "rare"; having to make up unused names is an obvious >>> smell in comparison. >>> >>> ```js >>> foo(UNUSED1, UNUSED2, x) >>> >>> foo(_, __, x) >>> >>> foo(,, x) >>> >>> foo(...[,, x]) >>> ``` >>> >>> The latter is shorter and more explicit and would not be any more >>> confusing if it became common. >>> >>> >>> On Sun, May 29, 2016 at 8:46 PM, Bob Myers <rtm at gol.com> wrote: >>> >>>> Eliding array elements is not "similar" to eliding function formal >>>> parameters. The latter is extremely rare, hardly readable, confusing, >>>> bug-prone, and unnecessary because there is already a "standard way" which >>>> is to use any old parameter name you want: >>>> >>>> ```js >>>> function foo(UNUSED1, UNUSED2, x) >>>> ```` >>>> >>>> Most linters will not complain, or there are ways to shut them up if >>>> they do. >>>> >>>> If you want to throw away an argument, just throw it away. >>>> >>>> ```js >>>> function skipFirstParam(fn) { return ((first, ...args) => fn(...args)); >>>> } >>>> >>>> `[1,2,3,4].map(skipFirstParam(i => i)); >>>> >>>> ``` >>>> >>>> Or use Renki's solution. >>>> >>>> Bob >>>> >>>> >>>> On Sun, May 29, 2016 at 9:23 PM, Cyril Auburtin < >>>> cyril.auburtin at gmail.com> wrote: >>>> >>>>> Similarly to: >>>>> >>>>> `var [,x,,y] = [1,2,3,4,5,6];` >>>>> >>>>> I think it could be interesting to let a field empty in function >>>>> arguments >>>>> >>>>> `[1,2,3,4].map( (,i) => i )`, `Array.from({length:10}, (,i) => i )` >>>>> >>>>> `function test(a,,b) { }` >>>>> >>>>> (but that would alter the current parsing, that doesn't allow it) >>>>> >>>>> Currently I often use `_` as a way to mark ignored fields, but when >>>>> there are more than 1 you need another identifier. A standard way would be >>>>> interesting rather >>>>> >>>>> _______________________________________________ >>>>> es-discuss mailing list >>>>> es-discuss at mozilla.org >>>>> https://mail.mozilla.org/listinfo/es-discuss >>>>> >>>>> >>>> >>>> _______________________________________________ >>>> es-discuss mailing list >>>> es-discuss at mozilla.org >>>> https://mail.mozilla.org/listinfo/es-discuss >>>> >>>> >>> >> > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.mozilla.org/pipermail/es-discuss/attachments/20160808/cfc81811/attachment-0001.html>