Extension Elements/Functions can only return XML nodes in node sets.

[John Krukoff]

XPath/XSLT extension functions/elements can only return XML nodes for extension elements, but can accept a wider range of inputs. For instance, with a simple echo extension function:

def extension( context, input ):
    return input

A "This is not a node" error is raised for a node set selection that includes text nodes (i.e. "//text()"). Ideally, extension functions should be able to return data of any type they accept. Tested with lxml 2.2.2.

Discussed on the mailing list here:
http://codespeak.net/pipermail/lxml-dev/2009-October/004939.html

[scoder (scoder)]

Implemented for strings in trunk rev. 68558:

https://codespeak.net/viewvc/?view=rev&revision=68558

Numbers and booleans are trickier as they would have to pass through string values. It's not clear to me how to make this work nicely. I think strings are the most important use case anyway.

[John Krukoff (jkrukoff)]

Well, strings are certainly the use case I have, so no complaints here. Thanks for the quick addition!

[scoder (scoder)]

Fixed in lxml 2.3alpha1.