On Tue, 12 Apr 2011 07:55:26 +0200, Allen Wirfs-Brock
al...@wirfs-brock.com wrote:
On Apr 11, 2011, at 6:45 PM, Axel Rauschmayer wrote:
var obj={}.valueOf.call(obj); // ToObject in case primitive value
passed
...
{}.valueOf is the same value as Object.prototype.valueOf assuming none
Object.prototype.valueOf as specified is essentially a call to the internal
ToObject operation that wrappers primitive values. I put it in to deal with
cases like getDefiningObject(some string, match)
Oh my, I've just consulted the ECMAScript spec and it's true. But isn't that
On Tue, Apr 12, 2011 at 3:57 AM, Lasse Reichstein
reichsteinatw...@gmail.com wrote:
On Tue, 12 Apr 2011 07:55:26 +0200, Allen Wirfs-Brock
al...@wirfs-brock.com wrote:
On Apr 11, 2011, at 6:45 PM, Axel Rauschmayer wrote:
var obj={}.valueOf.call(obj); // ToObject in case primitive value
On Apr 12, 2011, at 12:57 AM, Lasse Reichstein wrote:
In that case, why not just
obj = Object(obj);
It has the added advantage of not returning the global object for null and
undefined,
but just a plain new object (although either can be said to be wrong in this
case).
I used
On Tue, Apr 12, 2011 at 08:41, Allen Wirfs-Brock al...@wirfs-brock.com wrote:
In ES5
{}.valueOf.call(undefined)
doesn't yield the this object. In general, ES5 built-ins do not convert their
this parameter to the global object when it is undefined.
FYI
On 11/04/2011, at 05:14, Mark S. Miller wrote:
On Apr 10, 2011, at 22:18 , David Herman wrote:
function getDefiningObject(obj, key) {
if (!(key in obj))
throw new Error(key + key + not found);
while (!obj.hasOwnProperty(key))
That should be
while
On Sun, Apr 10, 2011 at 11:21 PM, David Herman dher...@mozilla.com wrote:
I wondered if someone was going to make this point.
That should be
while (!{}.hasOwnProperty.call(obj, key))
which works even if obj has an own property named 'hasOwnProperty'.
Not if someone mutates
On 11.04.2011 18:07, Mark S. Miller wrote:
On Sun, Apr 10, 2011 at 11:21 PM, David Herman dher...@mozilla.com
mailto:dher...@mozilla.com wrote:
I wondered if someone was going to make this point.
That should be
while (!{}.hasOwnProperty.call(obj, key))
Personally, I prefer Object.getOwnPropertyDescriptor as a property existence
test because it doesn't have the reflection the meta-circularity concern. I
would write Dave's original function as:
function getDefiningObject(obj, key) {
var obj={}.valueOf.call(obj); // ToObject in case
Le 10/04/2011 23:27, Dmitry A. Soshnikov a écrit :
On 11.04.2011 18:07, Mark S. Miller wrote:
On Sun, Apr 10, 2011 at 11:21 PM, David Herman dher...@mozilla.com
mailto:dher...@mozilla.com wrote:
I wondered if someone was going to make this point.
That should be
On Sun, Apr 10, 2011 at 5:27 PM, Dmitry A. Soshnikov
dmitry.soshni...@gmail.com wrote:
As I see it, you address the issue of unstratified meta-programming
(note, I take the issue in quotes, since there's no a single meaning
whether the unstratified meta-level is so bad).
It depends on how
2011/4/11 Mark S. Miller erig...@google.com:
We would like a notion of correctness that allows us to reason in a modular
manner: A correct composition of individually correct components should
yield a correct composite, where the correctness of the composition depends
only on the contracts of
On Mon, Apr 11, 2011 at 2:48 PM, Mike Samuel mikesam...@gmail.com wrote:
2011/4/11 Mark S. Miller erig...@google.com:
We would like a notion of correctness that allows us to reason in a
modular
manner: A correct composition of individually correct components should
yield a correct
On Apr 11, 2011, at 8:58 PM, David Bruant wrote:
Le 11/04/2011 21:47, Brendan Eich a écrit :
On Apr 11, 2011, at 6:36 PM, Allen Wirfs-Brock wrote:
Personally, I prefer Object.getOwnPropertyDescriptor as a property
existence test because it doesn't have the reflection the meta-circularity
On Apr 11, 2011, at 12:47 PM, Brendan Eich wrote:
Then the only downside is the pd allocation. Any way to avoid that?
/be
Use a GC that supports cheap allocation/recovery of short-lived objects :-)
It's probably premature optimization to worry about that one pd allocation
without
Le 11/04/2011 22:01, Brendan Eich a écrit :
On Apr 11, 2011, at 8:58 PM, David Bruant wrote:
Le 11/04/2011 21:47, Brendan Eich a écrit :
On Apr 11, 2011, at 6:36 PM, Allen Wirfs-Brock wrote:
Personally, I prefer Object.getOwnPropertyDescriptor as a property
existence test because it
On Apr 11, 2011, at 9:21 PM, David Bruant wrote:
Actually I was wrong I think. With the introduction of proxies, ES
engines won't be able to trivially prevent pd allocation as they could
with regular objects just based on static analysis (since static
analysis will often fail at saying
Sure, I'll buy that. There's a qualitative difference in how uncooperatively
your program is behaving if it mutates primordials to violate their usual
contracts, as opposed to simply creating an object that overrides
hasOwnProperty, which ought to be allowed.
The word theory might be a little
var obj={}.valueOf.call(obj); // ToObject in case primitive value passed
Can you explain how this works?
- Why {} and not Object.prototype?
- I know valueOf as a method that returns a primitive if an object can be
converted to one and |this|, otherwise. Oddly enough, this works both in
On Apr 11, 2011, at 6:45 PM, Axel Rauschmayer wrote:
var obj={}.valueOf.call(obj); // ToObject in case primitive value passed
Can you explain how this works?
- Why {} and not Object.prototype?
- I know valueOf as a method that returns a primitive if an object can be
converted to one
As far as I am aware, there is no way to change a property that isn’t at the
beginning of the property chain, because the change will create a new property
there.
Are there plans to change this? It would be nice to have something akin to
class methods (without accessing the prototype via some
On 10.04.2011 21:24, Axel Rauschmayer wrote:
As far as I am aware, there is no way to change a property that isn’t at the
beginning of the property chain, because the change will create a new property
there.
Are there plans to change this? It would be nice to have something akin to
class
Le 10/04/2011 19:24, Axel Rauschmayer a écrit :
As far as I am aware, there is no way to change a property that isn’t at the
beginning of the property chain, because the change will create a new
property there.
Are there plans to change this? It would be nice to have something akin to
function getDefiningObject(obj, key) {
if (!(key in obj))
throw new Error(key + key + not found);
while (!obj.hasOwnProperty(key))
obj = Object.getPrototypeOf(obj);
return obj;
}
On Apr 10, 2011, at 10:24 AM, Axel Rauschmayer wrote:
As far as I am aware, there is
Exactly what I was looking for. Thanks.
On Apr 10, 2011, at 22:18 , David Herman wrote:
function getDefiningObject(obj, key) {
if (!(key in obj))
throw new Error(key + key + not found);
while (!obj.hasOwnProperty(key))
obj = Object.getPrototypeOf(obj);
return obj;
As far as I am aware, there is no way to change a property that isn’t at the
beginning of the property chain, because the change will create a new
property there.
Are there plans to change this? It would be nice to have something akin to
class methods (without accessing the prototype via
On Sun, Apr 10, 2011 at 6:59 PM, Axel Rauschmayer a...@rauschma.de wrote:
Exactly what I was looking for. Thanks.
Not exactly...
On Apr 10, 2011, at 22:18 , David Herman wrote:
function getDefiningObject(obj, key) {
if (!(key in obj))
throw new Error(key + key + not
I wondered if someone was going to make this point.
That should be
while (!{}.hasOwnProperty.call(obj, key))
which works even if obj has an own property named 'hasOwnProperty'.
Not if someone mutates Object.prototype.hasOwnProperty or
Function.prototype.call. I don't think we
Exactly what I was looking for. Thanks.
Not exactly...
True. But it's OK for me as a work-around.
That should be
while (!{}.hasOwnProperty.call(obj, key))
which works even if obj has an own property named 'hasOwnProperty'.
IIRC, {} creates a new instance for each
29 matches
Mail list logo
