Just a thought on this.
If we can implement deep-equal($n1, $n2) as calculating some
ValueIdentity (VI) for each of the nodes and returning
VI1 eq VI2 ...
Then the VIs for each node can be calculated on the initial reading of
the XML document (even in streaming mode) with almost no additional
effort. If these VIs are made properties of the nodes, then we could
just compare the VIs of the nodes and avoid any repeated zip-like
comparison of the subtrees that are topped by these nodes. And this
also seems more declarative/functional.
Just my 2c.
Cheers,
Dimitre
On Thu, Apr 5, 2018 at 9:45 AM, Martin Honnen
martin(_dot_)honnen(_at_)gmx(_dot_)de
<xsl-list-service(_at_)lists(_dot_)mulberrytech(_dot_)com> wrote:
On 05.04.2018 18:12, Leo Studer leo(_dot_)studer(_at_)varioweb(_dot_)ch wrote:
I have an xml file where I need and XPath expression to find all elements
that are a copy of a previous element in the same file.
I came up with the following:
*let* *$xml* := <a>
<b>
<c>1</c>
<d>1</d>
<d>2</d>
</b>
<b>
<c>2</c>
<d>1</d>
<d>3</d>
</b>
<b>
<c>3</c>
<d>2</d>
<d>3</d>
</b>
<b>
<c>3</c>
<d>2</d>
<d>3</d>
</b>
</a>
*return*
*$xml*//*[*let**$node1*:=.*return**some**$node2**in**$xml*//*[.<<*$node1*]
*satisfies*/deep-equal/(*$node1*,*$node2*)]/(ancestor-or-self::/node/()//concat/(/node-name/(.),1+/count/(preceding-sibling::*)),' ')
which gives
a1 b2 d2
a1 b3 d2
a1 b3 d3
a1 b4
a1 b4 c1
a1 b4 d2
a1 b4 d3
This is actually not to bad. However, I would like the correct position of
the copy. Instead of preceding-sibling::/* /in the count() function, I would
like to write something like preceding-sibling::/element(node-name(.)).
/Unfortunately the processor does not allow that ;-(…
The code with $xml := <a>...</a> looks like XQuery to me, not like XSLT or
XPath. That aside, what do you want pseudo syntax
preceding-sibling::element(node-name(.))
to compute? If you want to select all elements and compare them to the
node-name() of another node you can certainly use
preceding-sibling::*[node-name() = node-name($n)]
where you simply would need to make sure you define $n previously with a
"let", as you have done at another place in your code.
Also XPath now has a "path" function which returns an XPath expression with
positional predicates so perhaps you don't need to construct the
name/position pairs on your own if you have access to the latest XPath
version.
--
Cheers,
Dimitre Novatchev
---------------------------------------
Truly great madness cannot be achieved without significant intelligence.
---------------------------------------
To invent, you need a good imagination and a pile of junk
-------------------------------------
Never fight an inanimate object
-------------------------------------
To avoid situations in which you might make mistakes may be the
biggest mistake of all
------------------------------------
Quality means doing it right when no one is looking.
-------------------------------------
You've achieved success in your field when you don't know whether what
you're doing is work or play
-------------------------------------
To achieve the impossible dream, try going to sleep.
-------------------------------------
Facts do not cease to exist because they are ignored.
-------------------------------------
Typing monkeys will write all Shakespeare's works in 200yrs.Will they
write all patents, too? :)
-------------------------------------
Sanity is madness put to good use.
-------------------------------------
I finally figured out the only reason to be alive is to enjoy it.
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