On Friday 16 March 2007 11:49, Stefan Behnel wrote:
Hi,
Stephan Richter wrote:
I have recently reimplemented RML (Reportlab's XML format to generate PDFs) using lxml. All works well.
Interesting. Any chance you could provide a link?
Sure: http://svn.zope.org/z3c.rml/trunk/src/z3c/rml/
Now, I would like to give my users some more information when an error occurs. For a pure XML parsing error, everything is fine (though I found the failure points hard to interpret at times). But what if the XML parses correctly, but while working with the element tree an error occurs? In this case I would like to tell the user not only the error message, but also the line/column and filename of point of failure.
This sounds a lot like a problem you could try to solve with validation.
No, I cannot, since some stuff cannot be decided until I do Python calls. For example, I look up colors by names, but this is not a static list.
Ideally I would have the filename, start row and start column of each element available as part of the etree Element. I have tried to find this information or hooks for it.unsuccessfully.
There is no API for it, but internally, we have this information for parsed trees, at least the line number - note that exceptions contain the line number already. So we could easily add a property "_line" to elements that returns the line number at which the element was parsed (*if* it was parsed). I don't like the fact so much that libxml2 puts a zero there if the node was created by hand, but I assume that is not too much of a problem either.
I think a zero is no problem. None would be better. :-)
I personally prefer "_line" over "line", as this only applies to parsed elements, not all of them, so this is more of a half-working API.
That would be perfect.
Additionally, any additional attribute there goes off the list of children accessible in objectify.
I don't understand this sentence. :-)
We could also consider adding an external utility module to provide helpers like this that are not really worth poluting the API. Something like
lxml.tools.lineof(element)
That would be icing on the cake; either way is fine, If you consider such a tool, I would probably call it "parseInfo" or so, where maybe the filename, endline, and column info is available too.
Any comments?
How fast can you do this? :-)
Regards, Stephan