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Re: [p2-dev] Match/Context naming
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I don't have a good alternate suggestion, but maybe this will trigger someone else to a better idea.
I think of a context query as one where the ability for something to "match" the query is "relative" to the other items being iterated.
Whereas the match query has the property that something that "matches" the query will always match the query, regardless of the other items involved.
MatchQuery
RelativeMatchQuery
???
susan
![Inactive hide details for Thomas Hallgren ---02/23/2010 01:34:52 PM---On 02/23/2010 09:56 PM, Ian Bull wrote:]()
Thomas Hallgren ---02/23/2010 01:34:52 PM---On 02/23/2010 09:56 PM, Ian Bull wrote:
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To: P2 developer discussions <p2-dev@xxxxxxxxxxx>
cc:
Subject: Re: [p2-dev] Match/Context naming |
On 02/23/2010 09:56 PM, Ian Bull wrote:
> I'm not a big fan of Each vs. All as it sounds like Each doesn't
> include all the results.
>
The names give a hint on what the _expression_ is applied to. When you
author the query, you must consider if the _expression_ is applied to
'each row' or to 'all rows'. The words Each and All are correlated, like
Min/Max, Single/Multiple, etc.
I'm not saying that Each and All are the best terms. I'm just pointing
out why I think they have some validity.
> Here is some background (why Jeff and I arrived at these names).
>
> MatchQueries are queries in which you can answer an elements inclusion
> by looking at the element alone. For example, is my name "Ian Bull".
> I doesn't matter who else is in the room. Context queries, on the
> other hand, require knowledge of all the other elements. Am I the
> tallest person in the room? This obviously depends on who else is in
> the room.
>
You still fit the description of being the tallest person. I.e. you
"match" that description.
> We broke the queries down this way because MatchQueries can be easily
> done in parallel. While you might be able to do ContextQueries in
> parallel, there is not general way.
>
That sounds like an evaluator implementation concern. Valid I'm sure,
but does it bring any clarity for the user who authors a query?
- thomas
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