[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: quiz on select vs copy-of
Michael, Dimitri. you are right it shouldn't be a dark corner, but it IS in practice. This does do people's heads in... and it's a source of bugs. I've been called on site by clients just to find and fix this particular problem quite a few times. The usual story goes as follows: "ah well we used to use select="" but then we had to add some choose and if and had to use a child element". Boom. Christian Michael Kay wrote: > This shouldn't be a dark corner, because the fact that nodes have identity > is pretty fundamental, but sadly there are lots of people who aren't aware > of the implications. The answer of course is (2). > > Michael Kay > http://www.saxonica.com/ > > >>-----Original Message----- >>From: Oleg A. Paraschenko [mailto:olpa@x...] >>Sent: 01 September 2005 20:45 >>To: xml-dev >>Subject: quiz on select vs copy-of >> >> Hello, >> >> do you know the dark corners of XSLT? Here is one. Compare two >>variables: >> >><xsl:variable name="v1" select="some-xpath"/> >><xsl:variable name="v2"><xsl:copy-of >>select="some-xpath"/></xsl:variable> >> >> Are "v1" and "v2" the same? I mean: can "v1" and "v2" be used in a >>program interchangeably? Answers: >> >>1) yes >>2) no >>3) implementation-dependant >> >>. >>. >>. >>. >>. >>. >>. >>. >>. >>. >>. >>. >>. >>. >>. >>. >>. >>. >>. >>. >>. >>. >>. >>. >> >> The right answer is (2): no. Changing a use of "v1" to >>"v2", or reverse, >>might change the result of a stylesheet. I'll post an example >>later. Or >>you can provide your version. >> >> >>-- >>Oleg Paraschenko olpa@ http://xmlhack.ru/ XML news in Russian >>http://uucode.com/blog/ Generative Programming, XML, TeX, Scheme >> >>----------------------------------------------------------------- >>The xml-dev list is sponsored by XML.org <http://www.xml.org>, an >>initiative of OASIS <http://www.oasis-open.org> >> >>The list archives are at http://lists.xml.org/archives/xml-dev/ >> >>To subscribe or unsubscribe from this list use the subscription >>manager: <http://www.oasis-open.org/mlmanage/index.php> >> > > > > ----------------------------------------------------------------- > The xml-dev list is sponsored by XML.org <http://www.xml.org>, an > initiative of OASIS <http://www.oasis-open.org> > > The list archives are at http://lists.xml.org/archives/xml-dev/ > > To subscribe or unsubscribe from this list use the subscription > manager: <http://www.oasis-open.org/mlmanage/index.php> > >
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