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RE: [IndexedDB] Spec changes for international language support

From: Pablo Castro <Pablo.Castro@microsoft.com>
Date: Tue, 22 Mar 2011 22:43:31 +0000
To: Keean Schupke <keean@fry-it.com>
CC: Jonas Sicking <jonas@sicking.cc>, Jungshik Shin <jshin@chromium.org>, Bjoern Hoehrmann <derhoermi@gmx.net>, public-webapps WG <public-webapps@w3.org>
Message-ID: <F108E2F6BA743C4696146F0B7111C2610EBA80@TK5EX14MBXC242.redmond.corp.microsoft.com>

From: keean.schupke@googlemail.com [mailto:keean.schupke@googlemail.com] On Behalf Of Keean Schupke
Sent: Friday, March 18, 2011 8:17 PM

>> On 18 March 2011 19:29, Pablo Castro <Pablo.Castro@microsoft.com> wrote:
>>
>> From: keean.schupke@googlemail.com [mailto:keean.schupke@googlemail.com] On Behalf Of Keean Schupke
>> Sent: Friday, March 18, 2011 1:53 AM
>>
>> >> See my proposal in another thread. The basic idea is to copy BDB. Have a primary index that is based on an integer, something primitive and fast. Allow secondary indexes which use a callback to generate a binary index key. IDB shifts the complexity out into a library. Common use cases can be provided (a hash of all fields in the object, internationalised bidirectional lexicographic etc...), but the user is free to write their own for less usual cases (for example indexing by the last word in a name string to order by surname).
I agree with Jeremy's comments on the other thread for this. Having the callback mechanism definitely sounds interesting but there are a ton of common cases that we can solve by just taking a language identifier, I'm not sure we want to make people work hard to get something that's already supported in most systems. The idea of having a callback to compute the index value feels incremental to this, so we could take on it later on without disrupting the explicit international collation stuff.
>>
>> The idea would be to provide pre-defined implementations of the callback for common use cases, then it is just as simple to register a callback as set any other option. All this means to the API is you pass a function instead of a string. It also is better for modularity as all the code relating to the sort order is kept in the callback functions.
>>
>> The difference comes down to something like:
>>
>> index.set_order_lexicographic('us');
>>
>> vs
>>
>> index.set_order_method(order_lexicographic('us'));
>>
>> So more than just setting a property like the first case, where presumably all the ordering code is mixed in with the indexing code, the second case encapsulates all the ordering code in the function returned from the execution of order_lexicographic('us'). This function would represent a mapping from the object being indexed to a binary blob that is the actual stored index data.
>>
>> So doing it this was does not necessarily make things harder, and it improves encapsulation, the type-safety, and the flexibility of the API.

Yep, we talked about supporting callbacks already in the other threads and in this one. As I mentioned before, I think this is an incremental to the basic feature of taking a collation name. I do realize you can just pass a pre-implemented function, but that opens the door to a bunch of things we'd need to handle, including storing possibly storing code in the database (such that proper updates don't depend on each page re-registering all the index callbacks), handling scripts with the appropriate context to run during index updates, etc.  I would much rather have basic functionality in place and then expand as needed once we have users using the API.

Thanks
-pablo
Received on Tuesday, 22 March 2011 22:44:05 GMT

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