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Re: [xsl] with XPath 1.0, select all following sibling elements of name "foo" up to the first non-"foo" element
2021-02-18 21:22:41
On Thu, Feb 18, 2021 at 6:24 PM G. Ken Holman
g(_dot_)ken(_dot_)holman(_at_)gmail(_dot_)com <
xsl-list-service(_at_)lists(_dot_)mulberrytech(_dot_)com> wrote:
Just eyeballing this, Dmitry, I'm not convinced
it would work if Wolfhart was sitting at a <foo>
at the time he made his request, in which case
the <foo> he was at would incorrectly be included.
My reading of the original question is that " Wolfhart is sitting" at the
first child element of the document (top) element. This is why the template
matches "/*/*[1]".
I believe that most variations of this question do have an efficient
solution using keys.
Cheers,
Dimitre
Granted the original requirement is
underspecified in this regard, so perhaps my
observation is irrelevant. I'm not trying to
nit-pick but I discounted the use of keys because
of the arbitrary starting point for evaluation.
Also the use= needs a "[1]" predicate to ensure
the correct cardinality for generate-id() in the
general case where there are multiple following siblings that are not
<foo>.
I'm usually successful with keys when not having
to deal with the current context.
Wolfhart, am I being too pedantic here?
. . . . . . Ken
At 2021-02-19 01:29 +0000, Dimitre Novatchev dnovatchev(_at_)gmail(_dot_)com
wrote:
Here is a short and efficient XSLT 1.0 solution using keys:
<xsl:stylesheet version="1.0"
xmlns:xsl="<http://www.w3.org/1999/XSL/Transform>
http://www.w3.org/1999/XSL/Transform";>
 <xsl:output omit-xml-declaration="yes" indent="yes"/>
 <xsl:key name="kPrecedingFoo" match="foo"
use="generate-id(following-sibling::*[not(self::foo)])"/>
Â
 <xsl:template match="/*/*[1]">
  <xsl:copy-of select="key('kPrecedingFoo',
generate-id(../*[not(self::foo)][1]))"/>
 </xsl:template>
</xsl:stylesheet>
Applying this transformation on variations of
the following XML document (try uncommenting
different subsets of the commented elements) produces always the wanted
result:
<t>
 <!-- <bar/> -->
 <foo ind="1"/>
 <foo ind="2"/>
 <!-- <bar/> -->
 <foo ind="3"/>
</t>
Cheers,
Dimitre
On Wed, Feb 17, 2021 at 5:32 PM Wolfhart
Totschnig
<mailto:wolfhart(_dot_)totschnig(_at_)mail(_dot_)udp(_dot_)cl>wolfhart(_dot_)totschnig(_at_)mail(_dot_)udp(_dot_)cl
<<mailto:xsl-list-service(_at_)lists(_dot_)mulberrytech(_dot_)com>
xsl-list-service(_at_)lists(_dot_)mulberrytech(_dot_)com>
wrote:
Dear list,
I am facing an XPath problem for which I cannot find the solution. I
want to select all following sibling elements of name "foo" up to the
first non-"foo" element. So, in the following case, the first two <foo>
elements should be selected:
<foo/>
<foo/>
<bar/>
<foo/>
In the following case, all three <foo> elements should be selected:
<foo/>
<foo/>
<foo/>
And in the following case, nothing should be selected:
<bar/>
<foo/>
<foo/>
I came up with the following non-working approach:
          <xsl:choose>
             <xsl:when
test="not(following-sibling::*[not(self::foo)])">
              Â
 <xsl:value-of select="following-sibling::*"/>
             </xsl:when>
             <xsl:otherwise>
                <xsl:value-of
select="following-sibling::*[not(self::source)][1]/preceding-sibling::*[self::source][preceding-sibling::current()]"/>
             </xsl:otherwise>
          </xsl:choose>
That is, test whether there are non-"foo" following siblings. If there
are none, take all following siblings. If there are, go forward to the
first non-"foo" sibling, and from there go backwards, taking all the
"foo" siblings up to the current node.
But this does not work. Apparently, the expression
"preceding-sibling::current()" is not a valid construct. So what is the
correct way to do what I have in mind (or a simpler solution, if there
is one). Please note that this stylesheet needs to be executed by a web
browser, and so the solution has to remain within XPath 1.0.
Thanks in advance for your help!
Wolfhart
--
Cheers,
Dimitre Novatchev
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--
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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