Re: [lxml-dev] Evaluate XSLT directives inside custom XSLT extension elements

Nov. 10, 2009

      Thanks for reply. It looks like it's not working as expected.

class MyExtElement(etree.XSLTExtension):
    def execute(self, context, self_node, input_node, output_parent):
        results = self.apply_templates(context, input_node)
        print results

This code causes:

Exception RuntimeError: 'maximum recursion depth exceeded while calling a
Python object' in 'lxml.etree._callExtensionElement' ignored
[<Element foo at 1007b0998>]
[<Element foo at 1007b0940>]
[<Element foo at 1007b0a48>]
[<Element foo at 1007b0aa0>]
[<Element foo at 1007b0af8>]
... and so on

for my example.

When I try input_node[0] instead of input_node:

        results = self.apply_templates(context, input_node[0])
        print results

results is empty list.

By the way, this simple code causes segmentation fault on my OSX, Linux and
Windows machines.

class MyExtElement(etree.XSLTExtension):
    def execute(self, context, self_node, input_node, output_parent):
        print input_node

--
Marat

On Tue, Nov 10, 2009 at 11:26 AM, Stefan Behnel <stefan_ml@behnel.de> wrote:
...
Hi,
please don't top-post.
Marat Dakota, 09.11.2009 10:13:
...
Than it looks like I don't completely understand how it works. Could you
please help me:
XSLT file is:
<xsl:stylesheet version="1.0"
    xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    xmlns:my="testns"
    extension-element-prefixes="my">
    <xsl:template match="/">
        <foo>
            <my:ext>
                <xsl:attribute name="test"><xsl:value-of select="111"
/></xsl:attribute>
                  blabla
            </my:ext>
        </foo>
    </xsl:template>
</xsl:stylesheet>
Ah, yes, attributes. Attributes are mapped to smart strings when passed
through Python code.
...
Function is:
def execute(self, context, self_node, input_node, output_parent):
    ?????
    print etree.tostring(deepcopy(self_node))
Remember that self_node is the extension element itself. It will not change
during the evaluation, so printing it is uninteresting.
...
What should I put instead of ????? to make self_node having attribute
named
test with "111" as value?
I tried to call self.apply_templates for everything (for self_node, for
self_node[0], even for input_node and output_parent).
I would guess that you want to call it on "input_node". Calling
.apply_templates() should return a string (although I never tested that),
which you can then add as a new attribute to the tree. You have to do that
manually, though. I would expect that "is_attribute" flag of the smart
string to be True in your case (see the XPath docs), that would allow you
to distinguish attributes from plain text context.
Stefan