[Xapian-discuss] ValueCountMatchSpy with collapse_key

[James Aylett]

In the first instance I think it should be done entirely within the ValueCountMatchSpy, since that can be done as a separate compilable file or module without modifying the Xapian API. It's probably not the most efficient way of doing things, but it will allow you to get it working without modifying the core at this point.

James

On 7 Oct 2012, at 19:24, Matthew Story <matthewstory at gmail.com> wrote:

> On Sun, Oct 7, 2012 at 2:23 PM, Matthew Story <matthewstory at gmail.com> wrote:
>> On Sun, Oct 7, 2012 at 12:48 PM, James Aylett <james-xapian at tartarus.org> wrote:
>>> 
>>> Someone else may be able to confirm this, but I think the problem is that MatchSpy instances get called very low down in the matcher stack, while collapsing happens at a much higher level. Given that collapsing is relatively simple, it should be pretty easy to provide an alternative to ValueCountMatchSpy which takes collapsing into account as well.
>>> 
>>> If you wanted to make the alterations to the existing implementation, it'd be great if you could contribute them back under suitable licenses (see HACKING) so others can benefit. It would probably make sense for us only to have one implementation, with collapsing support being an option – but others should weigh in on this, as a maybe a better way to present this.
>>> 
>>> If C++ isn't your thing, you may have to wait for someone to have time – unless someone can come up with another way of tackling this.
>> 
>> Don't mind submitting a patch if the behavior is indeed undesirable.
>> Question is, what is the right approach to resolving this.  Should the
>> ValueCountMatchSpy be provided with the ability to ignore or respect
>> collapse, and then internally to itself track the collapse state based
>> on a collapse key provided to operator?  Or should the
>> ValueCountMatchSpy termfreq be decremented by MatchDecider at the
>> collapse phase.
>> 
>> Relatively new user, so not sure as to the best path (in line with the
>> design of the project, and with regards to efficiency) towards
>> resolution.
>> 
>> Suggestions?
>> [...snip]
> 
> Replying to list, with apologies to James.
> 
> 
> 
> 
> -- 
> regards,
> matt
> 
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-- 
 James Aylett, occasional trouble-maker
 xapian.org