Presence of a node in a node set

EastvanAxon · May 24th, 2013, 06:29 AM

Dear all,

Once again I need your help

I'm trying to replace a node N with a node N1, only if N is deep-equal() to a node stored into a variable V. The tricky part is that if such a node N does not exist, I have to add the node V to the original set of nodes, i.e.

Code:

<list>
  <node1>
  <node2>
  <node3>
</list>

has to become

Code:

<list>
  <v>
  <node2>
  <node3>
</list>

if "deep-equal($node1, $v) = true()"

or

Code:

<list>
  <node1>
  <v>
  <node3>
</list>

if "deep-equal($node2, $v) = true()"

or

Code:

<list>
  <node1>
  <node2>
  <v>
</list>

if "deep-equal($node3, $v) = true()"

or, finally,

Code:

<list>
  <node1>
  <node2>
  <node3>
  <v>
</list>

if no node in ($node1, $node2, $node3) is deep-equal to $v
[suppose that $node{1,2,3} are variables storing the nodes with the same name() of the variable, and that <node{1,2,3}> are nodes with children]

I tried different approaches...using index-of was the one more promising because I could use a variable to store the sequence of nodes under <list> and then check index-of($list-of-nodes, $v)...sadly this function does not use deep-equal to check the equality of $v and the items in $list-of-nodes, thus it doesn't work for my case, where I might have two nodes with same name() but different attributes or other differences in their children that I must consider

Do you have any suggestion?

Thanks in advance for your help!!!

Martin Honnen · May 24th, 2013, 06:39 AM

Write a template

Code:

<xsl:template match="list[not(*[deep-equal(., $v)])]">
  <xsl:copy>
     <xsl:copy-of select="node(), $v"/>
  </xsl:copy>
</xsl:template>

together of course with the identity transformation template.

I don't think you need a template to replace node1 or node2 or node3 if they are deep-equal to the node in the variable as that would not change the result.

If you think you need to then use

Code:

<xsl:template match="list/node1[deep-equal(., $v)] | list/node2[deep-equal(., $v)] | list/node3[deep-equal(., $v)]">
  <xsl:copy-of select="$v"/>
</xsl:template>

EastvanAxon · May 24th, 2013, 06:47 AM

Thanks for your reply Martin,

I don't understand how the template is able to add the node in $v just one time, when no list/* are deep-equal to $v.

because your first template seems to add $v for every node that is not deep-equal to $v, or am I wrong?

Can't I use the check you put in the match attribute of that first template to check if I have to add $v, and thus use a <choose> to split the two cases (where there is a node deep-equal and where there isn't one)?

Martin Honnen · May 24th, 2013, 07:08 AM

The first template I posted matches on
list[not(*[deep-equal(., $v)])]
so it looks at the "list" elements not containing a single child element that is deep-equal to the variable "v".
It does a shallow copy of the "list" element and inside a deep copy of all child nodes and of a single instance of the variable "v" so I don't see why it would add "v" several times.

EastvanAxon · May 24th, 2013, 08:17 AM

Ah ok, thx.

BTW I got confused, the check is with another node stored into the variable $n and not $v, because $v stores the node that has to be used for replacement

I solved the problem without using the template. I used a choose and checked when "count(list/*[deep-equal(., $n1)])=0". If that is true I use for-each "list/*" and do copy-of "." and finally "$v". Otherwise I used another for-each with another choose (to check whenever deep-equal(., $n1) is true and replace "." with $v)

I know that this is not probably the best solution, but I tested it and it's working

Thanks a lot for your help, that matching condition was of inspiration