On 2009-12-15, at 23:28, Brendan Eich wrote:
Something more like Self, in other words. I still wonder if we can't recover
that lost form, enable prototype-based composition as Tucker wanted, and
banish host objects to the ninth circle of hell, in a future edition.
We can dream! :)
On 15/12/2009, at 13:51, P T Withington wrote:
(...)
I once had the vain hope that I could say:
function MyArray () {}
MyArray.prototype = [];
to create my own subclasses of Array. That might have lessened the need for
isArrayLike.
For that, we'd need an Array.create(). It might be
On Dec 15, 2009, at 4:51 AM, P T Withington wrote:
On 2009-12-08, at 13:10, Mike Samuel wrote:
All true. And yet it is not uncommon. See the bottom of this email
for a quick survey of a number of libraries' uses of the array-like
concept.
FWIW, Here is the (separately/simultaneously
On Dec 15, 2009, at 5:05 AM, Jorge Chamorro wrote:
On 15/12/2009, at 13:51, P T Withington wrote:
(...)
I once had the vain hope that I could say:
function MyArray () {}
MyArray.prototype = [];
to create my own subclasses of Array. That might have lessened the
need for isArrayLike.
For
On 15/12/2009, at 16:21, Brendan Eich wrote:
On Dec 15, 2009, at 5:05 AM, Jorge Chamorro wrote:
On 15/12/2009, at 13:51, P T Withington wrote:
(...)
I once had the vain hope that I could say:
function MyArray () {}
MyArray.prototype = [];
to create my own subclasses of Array. That
On Dec 15, 2009, at 8:46 AM, Jorge Chamorro wrote:
It's the same functionality provided by Object.create(), but for []
instead of {}.
Ah, that helps -- thanks. This is not exactly what Tucker showed,
though.
Tucker is looking for a way to compose custom [[Put]] with
prototype-based
Brendan Eich wrote:
In ES specs and real implementations, internal methods and various
corresponding implementation hooks are called based on [[Class]] of the
directly referenced object, in contrast.
In ES specs, there's no indication that [[Class]] can or should be used
for internal method
On Dec 15, 2009, at 11:18 AM, David-Sarah Hopwood wrote:
Brendan Eich wrote:
In ES specs and real implementations, internal methods and various
corresponding implementation hooks are called based on [[Class]] of
the
directly referenced object, in contrast.
In ES specs, there's no
Brendan Eich wrote:
On Dec 15, 2009, at 11:18 AM, David-Sarah Hopwood wrote:
Brendan Eich wrote:
In ES specs and real implementations, internal methods and various
corresponding implementation hooks are called based on [[Class]] of the
directly referenced object, in contrast.
[...]
Sorry, I
2009/12/13 Garrett Smith dhtmlkitc...@gmail.com:
On Sun, Dec 13, 2009 at 10:31 AM, Mike Samuel mikesam...@gmail.com wrote:
2009/12/12 Garrett Smith dhtmlkitc...@gmail.com:
On Sat, Dec 12, 2009 at 4:04 PM, Mark S. Miller erig...@google.com wrote:
On Sat, Dec 12, 2009 at 3:38 PM, Garrett Smith
On Mon, Dec 14, 2009 at 9:34 AM, Mike Samuel mikesam...@gmail.com wrote:
2009/12/13 Garrett Smith dhtmlkitc...@gmail.com:
On Sun, Dec 13, 2009 at 10:31 AM, Mike Samuel mikesam...@gmail.com wrote:
2009/12/12 Garrett Smith dhtmlkitc...@gmail.com:
On Sat, Dec 12, 2009 at 4:04 PM, Mark S. Miller
On Tue, Dec 15, 2009 at 6:29 AM, Mike Samuel mikesam...@gmail.com wrote:
(3) If (!1), should future EcmaScript drafts define iteration order
for arrays as index order and possibly recommend to array like host
objects that the define iteration order similarly.
I would suggest that this change
2009/12/14 Breton Slivka z...@zenpsycho.com:
On Tue, Dec 15, 2009 at 6:29 AM, Mike Samuel mikesam...@gmail.com wrote:
(3) If (!1), should future EcmaScript drafts define iteration order
for arrays as index order and possibly recommend to array like host
objects that the define iteration order
On Tue, Dec 15, 2009 at 10:34 AM, Mike Samuel mikesam...@gmail.com wrote:
2009/12/14 Breton Slivka z...@zenpsycho.com:
On Tue, Dec 15, 2009 at 6:29 AM, Mike Samuel mikesam...@gmail.com wrote:
(3) If (!1), should future EcmaScript drafts define iteration order
for arrays as index order and
On Mon, Dec 14, 2009 at 11:29 AM, Mike Samuel mikesam...@gmail.com wrote:
2009/12/14 Garrett Smith dhtmlkitc...@gmail.com:
On Mon, Dec 14, 2009 at 9:34 AM, Mike Samuel mikesam...@gmail.com wrote:
2009/12/13 Garrett Smith dhtmlkitc...@gmail.com:
On Sun, Dec 13, 2009 at 10:31 AM, Mike Samuel
On Dec 12, 2009, at 12:36 PM, Mark S. Miller wrote:
On Sat, Dec 12, 2009 at 12:29 PM, Garrett Smith dhtmlkitc...@gmail.com
wrote:
Object.prototype.propertyIsEnumerable does not consider properties in
the prototype chain. In effect, propertyIsEnumerable is a test to see
if an object has *own*
David-Sarah Hopwood wrote:
Mark S. Miller wrote:
function isArrayLike(obj) {
var len;
return !!(obj
typeof obj === 'object'
'length' in obj
!({}).propertyIsEnumerable.call(obj, 'length')
(len = obj.length) 0 === len);
}
If
On Fri, Dec 11, 2009 at 12:08 PM, Mike Wilson mike...@hotmail.com wrote:
Mark S. Miller wrote:
If we're looking for a convention that is
* does not admit any legacy ES3R non-array non-host objects (to prevent
false positives)
No native ES objects?
* does easily allow ES5 programmers to
Mark S. Miller wrote:
On Sat, Dec 12, 2009 at 10:36 AM, Mike Samuel mikesam...@gmail.com wrote:
On the String defect, we could repair that with
({}).toString.call(obj) !== '[object String]'
Cons:
An extra function call in the likely case
Strings are arguable array-like
Pros:
Strings
On Dec 12, 2009, at 11:36 AM, Mike Wilson wrote:
Mark S. Miller wrote:
On Sat, Dec 12, 2009 at 10:36 AM, Mike Samuel mikesam...@gmail.com
wrote:
On the String defect, we could repair that with
({}).toString.call(obj) !== '[object String]'
Cons:
An extra function call in the likely
On Dec 12, 2009, at 10:36 AM, Mike Samuel wrote:
2009/12/12 Mike Wilson mike...@hotmail.com:
David-Sarah Hopwood wrote:
Mark S. Miller wrote:
function isArrayLike(obj) {
var len;
return !!(obj
typeof obj === 'object'
'length' in obj
On Sat, Dec 12, 2009 at 12:01 PM, Mark S. Miller erig...@google.com wrote:
On Sat, Dec 12, 2009 at 11:21 AM, Garrett Smith dhtmlkitc...@gmail.com
wrote:
On Fri, Dec 11, 2009 at 12:08 PM, Mike Wilson mike...@hotmail.com wrote:
Mark S. Miller wrote:
If we're looking for a convention that
On Sat, Dec 12, 2009 at 12:29 PM, Garrett Smith dhtmlkitc...@gmail.comwrote:
Object.prototype.propertyIsEnumerable does not consider properties in
the prototype chain. In effect, propertyIsEnumerable is a test to see
if an object has *own* property that is also enumerable.
And just when I
On Sat, Dec 12, 2009 at 12:29 PM, Garrett Smith dhtmlkitc...@gmail.com
wrote:
Object.prototype.propertyIsEnumerable does not consider properties in
the prototype chain. In effect, propertyIsEnumerable is a test to see
if an object has *own* property that is also enumerable.
At the end of
On Sat, Dec 12, 2009 at 3:38 PM, Garrett Smith dhtmlkitc...@gmail.comwrote:
On Sat, Dec 12, 2009 at 2:59 PM, Mark S. Miller erig...@google.com
wrote:
Are we really this stuck? Can anyone think of a reliable, portable, and
fast
ES3R test that tests whether a property is enumerable, whether
2009/12/12 Brendan Eich bren...@mozilla.com:
On Dec 12, 2009, at 10:36 AM, Mike Samuel wrote:
2009/12/12 Mike Wilson mike...@hotmail.com:
David-Sarah Hopwood wrote:
Mark S. Miller wrote:
function isArrayLike(obj) {
var len;
return !!(obj
typeof obj === 'object'
2009/12/12 Garrett Smith dhtmlkitc...@gmail.com:
On Fri, Dec 11, 2009 at 12:08 PM, Mike Wilson mike...@hotmail.com wrote:
Mark S. Miller wrote:
If we're looking for a convention that is
* does not admit any legacy ES3R non-array non-host objects (to prevent
false positives)
No native ES
On Sat, Dec 12, 2009 at 4:04 PM, Mark S. Miller erig...@google.com wrote:
On Sat, Dec 12, 2009 at 3:38 PM, Garrett Smith dhtmlkitc...@gmail.com
wrote:
On Sat, Dec 12, 2009 at 2:59 PM, Mark S. Miller erig...@google.com
wrote:
Are we really this stuck? Can anyone think of a reliable,
I think Breton mentions something important here; the desire
to actually detect if something is an array or arraylike to
be able to branch to different code that does completely
different things for array[likes] and objects. If we just
provide a better generic iteration construct then this part
is
On Fri, Dec 11, 2009 at 2:27 AM, Mike Wilson mike...@hotmail.com wrote:
I think Breton mentions something important here; the desire
to actually detect if something is an array or arraylike to
be able to branch to different code that does completely
different things for array[likes] and
[+commonjs]
On Fri, Dec 11, 2009 at 12:08 PM, Mike Wilson mike...@hotmail.com wrote:
Thanks Mark, this is the right way to approach it I think. String objects
will be considered array-like above which may not be desired, but either
way, I think it is this type of guideline that can prove
Mark S. Miller wrote:
On Fri, Dec 11, 2009 at 2:27 AM, Mike Wilson mike...@hotmail.com wrote:
I think Breton mentions something important here; the desire
to actually detect if something is an array or arraylike to
be able to branch to different code that does completely
different things
2009/12/8 Mike Samuel mikesam...@gmail.com:
It occurred to me after looking at the proxy strawman that it might
help to nail down what array-like means in future drafts. It isn't
directly related to the proxy stuff though so I thought I'd start a
separate thread.
I've seen quite a bit of
2009/12/8 Erik Corry erik.co...@gmail.com:
2009/12/8 Mike Samuel mikesam...@gmail.com:
It occurred to me after looking at the proxy strawman that it might
help to nail down what array-like means in future drafts. It isn't
directly related to the proxy stuff though so I thought I'd start a
On Dec 8, 2009, at 1:10 PM, Mike Samuel wrote:
2009/12/8 Erik Corry erik.co...@gmail.com:
2009/12/8 Mike Samuel mikesam...@gmail.com:
It occurred to me after looking at the proxy strawman that it might
help to nail down what array-like means in future drafts. It isn't
directly related to
Ok, let's think about a new loop construct.
Adding new syntax makes for-in a boat-anchor implementations lug
around, in the best case. But realistically it will be years before
developers can count on the new loop construct. And as support comes
online, developers will have to choose which
2009/12/8 Brendan Eich bren...@mozilla.com:
On Dec 8, 2009, at 10:10 AM, Mike Samuel wrote:
1) Does the object have the special semantics around .length? This is
potentially useful to know and the normal way to find out doesn't
work. Instanceof is affected by setting __proto__, yet the
2009/12/8 Brendan Eich bren...@mozilla.com:
On Dec 8, 2009, at 11:51 AM, Erik Corry wrote:
for (let i in arraylike) {
i |= 0;
If this pattern catches on then we could optimize for it without
changing the language.
Yeah, but some day there will be only new versions in which i is numeric
On Dec 8, 2009, at 12:52 PM, Mike Samuel wrote:
2009/12/8 Brendan Eich bren...@mozilla.com:
On Dec 8, 2009, at 11:51 AM, Erik Corry wrote:
for (let i in arraylike) {
i |= 0;
If this pattern catches on then we could optimize for it without
changing the language.
Yeah, but some day there
Your strawman would support:
{0: strawman, length: 0}
A better definition might be:
o is an array like object if o[[Get]]('length') returns a Number one
greater than the largest numeric property, or 0 if no numeric properties
exist.
Yehuda Katz
Developer | Engine Yard
(ph) 718.877.1325
On
be used for all array-like situations.
Allen
From: es-discuss-boun...@mozilla.org [mailto:es-discuss-boun...@mozilla.org] On
Behalf Of Yehuda Katz
Sent: Monday, December 07, 2009 5:40 PM
To: mikesam...@gmail.com
Cc: es-discuss
Subject: Re: array like objects
Your strawman would support:
{0
2009/12/7 Yehuda Katz wyc...@gmail.com:
Your strawman would support:
{0: strawman, length: 0}
A better definition might be:
o is an array like object if o[[Get]]('length') returns a Number one
greater than the largest numeric property, or 0 if no numeric properties
exist.
By that better
The one that I use is
function isArrayLike(i){
return (typeof i !==string) i.length !== void (0);
}
It might not be perfect, but it allows me to make certain assumptions
about the input that are useful enough. Keep in mind that an Array may
have a length of 5, and all those values are
On Tue, Dec 8, 2009 at 1:29 PM, Breton Slivka z...@zenpsycho.com wrote:
The one that I use is
function isArrayLike(i){
return (typeof i !==string) i.length !== void (0);
}
It might not be perfect, but it allows me to make certain assumptions
about the input that are useful enough. Keep
From: es-discuss-boun...@mozilla.org [mailto:es-discuss-boun...@mozilla.org]
On Behalf Of Yehuda Katz
Sent: Monday, December 07, 2009 5:40 PM
To: mikesam...@gmail.com
Cc: es-discuss
Subject: Re: array like objects
Your strawman would support:
{0: strawman, length: 0}
A better
2009/12/7 Breton Slivka z...@zenpsycho.com:
The one that I use is
function isArrayLike(i){
return (typeof i !==string) i.length !== void (0);
I like that it's efficient.
How about
if (i !== null typeof i === 'object') {
var len = i.length;
var ilen = len 0;
return
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