[Twisted-Python] Status of twisted.xish.xpath

Donovan Preston dp at ulaluma.com
Mon Apr 12 12:18:32 EDT 2004

On Apr 12, 2004, at 11:59 AM, Dave Smith wrote:

>> I was wondering what's the status of the xpath parser in Twisted.
> Well, xish.xpath isn't meant to be a "full" xpath implementation, per 
> se.
> I originally wrote it be used for routing XML packets from a Jabber
> connection, so it's really focused on providing matching/equality
> operations versus the transforms and other operations traditionally
> associated with XPath engines. In my happy little world, XPath is not a
> operational language -- it's a filtering/matching syntax.

Does XPath actually specify transformation operations? I thought that 
was up to something like XSLT. I agree that XPath should only be used 
for node matching, and that transformation should be done in other 

> I wasn't aware that Nevow was using xish.xpath, but that's cool if it 
> is.
> I'll be glad to add additional logic as necessary to enhance the
> filtering/matching aspects of XPath to support a RSS aggregator, but 
> I'd
> prefer to not see xish.xpath become a "full" XPath engine.

This is not related to the current discussion, but I have been 
contemplating replacing nevow's fixed scheme which only looks for nodes 
with nevow 'specials' on them (such as render and data) with a 
dictionary of {xpath expression object: transformation function}. It is 
not something I am planning on doing right away, but eventually, and it 
would be nice to use some existing code for this.

> FWIW, xish.xpath is "actively developed", there just haven't been any
> feature or bug requests against it for a while. :)

I wish more software were in this mode. "It's flexible enough to use 
without having to change the internals" is the holy grail of software 


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