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Xerces only supports the simplest XPath queries?

 
 
John W Kennedy
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      06-04-2012
On 2012-06-04 12:25:02 +0000, Ramon F Herrera said:

> On Jun 2, 11:12*pm, Joe Kesselman <(E-Mail Removed)>
> wrote:
>
> > IBM's internal fork of that code does still compile and run,
> > but isn't generally available so that doesn't help you.

>
> "internal fork"?
>
> That sounds like a violation of the OS license...


I don't offhand recall ever hearing of any OS license that doesn't
allow an internal fork, so long as source and object are both internal.

--
John W Kennedy
"The blind rulers of Logres
Nourished the land on a fallacy of rational virtue."
-- Charles Williams. "Taliessin through Logres: Prelude"

 
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Ramon F Herrera
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      06-04-2012
On Jun 4, 9:36*am, John W Kennedy <(E-Mail Removed)> wrote:
> On 2012-06-04 12:25:02 +0000, Ramon F Herrera said:
>
> > On Jun 2, 11:12 pm, Joe Kesselman <(E-Mail Removed)>
> > wrote:

>
> > *> IBM's internal fork of that code does still compile and run,
> > *> but isn't generally available so that doesn't help you.

>
> > "internal fork"?

>
> > That sounds like a violation of the OS license...

>


> I don't offhand recall ever hearing of any OS license that doesn't
> allow an internal fork, so long as source and object are both

internal.

That's a very good point - and now that I think about it, I do it all
the time!

Still, I thought that when it comes to OSS contributions, IBM was one
of the good guys. Take for instance the fact that Big Blue invested
more money and resources into Java than Sun itself, and now Oracle
wants to steal all that. (The judge deserves standing ovations).

-Ramon
 
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John W Kennedy
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      06-04-2012
On 2012-06-04 14:49:03 +0000, Ramon F Herrera said:

> On Jun 4, 9:36*am, John W Kennedy <(E-Mail Removed)> wrote:
>> On 2012-06-04 12:25:02 +0000, Ramon F Herrera said:
>>
>>> On Jun 2, 11:12 pm, Joe Kesselman <(E-Mail Removed)>
>>> wrote:

>>
>>> *> IBM's internal fork of that code does still compile and run,
>>> *> but isn't generally available so that doesn't help you.

>>
>>> "internal fork"?

>>
>>> That sounds like a violation of the OS license...

>>

>
> > I don't offhand recall ever hearing of any OS license that doesn't
> > allow an internal fork, so long as source and object are both

> internal.
>
> That's a very good point - and now that I think about it, I do it all
> the time!
>
> Still, I thought that when it comes to OSS contributions, IBM was one
> of the good guys. Take for instance the fact that Big Blue invested
> more money and resources into Java than Sun itself, and now Oracle
> wants to steal all that. (The judge deserves standing ovations).


Without knowing what this internal fork is about, it's impossible to
say. It might just be a case of modifying it to meet internal IBM
standards, or to deal with an existing IBM database.

--
John W Kennedy
"Compact is becoming contract,
Man only earns and pays."
-- Charles Williams. "Bors to Elayne: On the King's Coins"

 
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Joe Kesselman
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      06-04-2012
On 6/4/2012 8:25 AM, Ramon F Herrera wrote:
> "internal fork"?
> That sounds like a violation of the OS license...


Nope. The Apache license explicitly permits commercializing their code,
as long as they are given appropriate credit for the contribution, and
encourates but does not require that changes be contributed back to Apache.

> In any event, XQilla works great BUT you take a performance hit
> (compared with the minimum implementation XPath performed by Xerces-
> C). The factor is 4x.


Going beyond the minimal subset may require building an in-memory data
model of the document, since full XPath can bounce around the document
both forward and backward. That does impose some costs. Beyond that,
it's a question of how clever and well-optimized the code is.

--
Joe Kesselman,
http://www.love-song-productions.com...lam/index.html

{} ASCII Ribbon Campaign | "may'ron DaroQbe'chugh vaj bIrIQbej" --
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Joe Kesselman
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      06-04-2012
On 6/4/2012 10:49 AM, Ramon F Herrera wrote:
> Still, I thought that when it comes to OSS contributions, IBM was one
> of the good guys.


IBM contributed Xerces and Xalan (both Java and C++) to Apache in the
first place, and provided a LOT of man-hours (including supporting Sun's
contributions to Xalan after Sun lost interest). IBM is no longer
officially involved in these two projects but continues to be involved
with open source in other areas. I think the dues have been paid...

--
Joe Kesselman,
http://www.love-song-productions.com...lam/index.html

{} ASCII Ribbon Campaign | "may'ron DaroQbe'chugh vaj bIrIQbej" --
/\ Stamp out HTML mail! | "Put down the squeezebox & nobody gets hurt."
 
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Peter Flynn
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      06-04-2012
On 02/06/12 20:35, Ramon F Herrera wrote:
> On Jun 1, 5:56 am, Martin Honnen <(E-Mail Removed)> wrote:
>> Ramon F Herrera wrote:
>>
>>> I have been using Xerces to perform XPath retrievals. So far, I have
>>> only dealt with the simplest path syntax. Much to my dismay, when I
>>> tried something a little fancier (a path with a subscript), it failed:

>>
>>> /root/table/detailed_steel_pole_usages[1]/joint_label

>>
>>> I guess I need some layer on top of Xerces-C?

>>

>
> > I am not familiar with details of Xerces-C, I think it has
> > a user mailing list where you are more likely to find other
> > users than here.

>
> I have used the mailing list/newsgroup, but EVERY time I ask a
> question, the answer is the same: somebody offers me a "better"
> alternative to Xerces. This is easily the most frustrating software I
> have used in my long life as programmer.


What are these "retrievals", exactly? Are you coding this inside some
other program in Java or C++ or something (ie using the Xerces and Xalan
libraries), or is this a shell script, or a web page, or ad-hoc
command-line queries, or what?

There are lots of tools out there; perhaps evaluating them is a good start.

///Peter
 
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