On May 20, 2008, at 2:56 PM, Robert O'Callahan wrote:
On Tue, May 20, 2008 at 3:50 PM, Maciej Stachowiak <[EMAIL PROTECTED]>
wrote:
On May 19, 2008, at 4:54 PM, Robert O'Callahan wrote:
If "storage.keyName = 'value';" can create a new storage item
(persistently), won't authors expect "delete storage.keyName;" to
remove it (persistently), as a matter of consistency?
If overloading "delete" is too quirky or too hard to implement, then
it seems none of the other shorthands should be allowed either.
Many objects in the DOM implement custom name getters (for instance
NodeList) and a few even implement custom name setters
(CSSStyleDeclaration, at least the way it is done in WebKit) but no
one has clamored for a custom deleter or expected delete to work "as
a matter of consistency" or been confused that "style.opacity = 0"
is allowed but "delete style.opacity" is not. So I would say the
available evidence argues against your conclusions.
I think 'style' does not bear on my conclusions, since 'style' has
custom property getters and setters, but not *adders* ---
"style.foobar = ...;" does not trigger any DOM API. Storage is
different, it is something new.
style.opacity = ... certainly triggers DOM API even if opacity was not
previously set on that style. And there is even a plausible mapping
for delete (style.removeProperty). It's not completely open-ended but
you can certainly have properties added to and removed from a style
declaration.
Ultimately the conclusion I question is that having obj.foo and
obj.foo = ... work, but not delete obj.foo, will create confusion or
is somehow illogical. I don't believe it will create confusion, and I
think style is a relevant example of a case where it has not.
Regards,
Maciej
