[whatwg] WebIDL vs HTML5 storage changes

Cameron McCormack cam at mcc.id.au
Sun May 18 15:54:44 PDT 2008

Hi Brady.

Brady Eidson:
> A little while ago, this change - 
> http://html5.org/tools/web-apps-tracker?from=1429&to=1430 - was meant to 
> "update the spec for consistency with WebIDL"
> In this change, the following passage was removed from the Storage  
> section:
> "In the ECMAScript DOM binding, enumerating a Storage object must  
> enumerate through the currently stored keys in the list the object is  
> associated with. (It must not enumerate the values or the actual members 
> of the interface). In the ECMAScript DOM binding, Storage objects must 
> support dereferencing such that getting a property that is not a member 
> of the object (i.e. is neither a member of the Storage interface nor of 
> Object) must invoke the getItem() method with the property's name as the 
> argument, and setting such a property must invoke the setItem() method 
> with the property's name as the first argument and the given value as the 
> second argument."
> Shorty thereafter, the declaration of the Storage interface was changed 
> to the following:
> interface Storage {
>     readonly attribute unsigned long length;
>     [IndexGetter] DOMString key(in unsigned long index);
>     [NameGetter] DOMString getItem(in DOMString key);
>     [NameSetter] void setItem(in DOMString key, in DOMString data);
>     [XXX] void removeItem(in DOMString key);
>     void clear();
> };
> I assumed that the WebIDL descriptions of [IndexGetter], [NameGetter],  
> and [NameSetter] would keep the specified functionality in tact, but it 
> appears this is *not* the case.
> Or by reading http://dev.w3.org/2006/webapi/Binding4DOM/ I can't find  
> where it is the case...
> Does someone know what is up with this?

Yeah, Web IDL doesn’t currently have a way to make a property DontEnum,
so the IDL there isn’t strictly equivalent to the prose that used to be

> While I'm on the topic, I'm also curious about that [XXX] placeholder.
> There's a bug in WebKit's bugzilla pointing out that the IE8 beta and  
> Firefox 2 both support  `delete storage.keyName` syntax as an alias for 
> `storage.removeItem(keyName)`
> I'm taking a guess here and assuming supporting the `delete` syntax is  
> the implied concept behind [XXX]


> Not that this mailing list has direct impact on the WebIDL spec, but I  
> would suggest [NameDeleter] or [NameRemover] as a placeholder in the  
> HTML5 spec since it fits in with the NameGetter/Setter family of  
> operations quite nicely.

They’re sensible names.  I’ll append() that on my TODO list.



Cameron McCormack ≝ http://mcc.id.au/

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