Hi,
Quoting Steven Nunez (steve_nunez@yahoo.com):
Greetings all,
I'm a bit stumped by some of the STP functions and usage. The documentation is, well, a bit sparse, so it's not clear whether there really is a bug or I'm mis-interpreting what I'm reading. Here is a simple function that should return all the child nodes of an element with the local-name of 'RegressionModel':
(defun function-name (document) "Return the PMML model type of the document" (stp:filter-recursively (stp:of-name "RegressionModel") (stp:first-child document)))
The call to OF-NAME is the problem, it needs to be (stp:of-name "RegressionModel" "http://www.dmg.org/PMML-4_0") because:
According to the documentation of filter-recursively: Return a list of descendant nodes of node in pre-order, from which nodes that do not satisfy predicate have been removed.and that for of-name: This function creates a test function for nodes of this name.
The function returned will return T if the argument is an instance of attribute or element and has the specified local-name and namespace URI, and will return NIL otherwise.
If local-name is nil, only the namespace URI is considered for comparison.
your element is in the http://www.dmg.org/PMML-4_0 namespace, whereas you specified the empty namespace.
Roughly speaking, local-name == SYMBOL-NAME namespace-uri == SYMBOL-PACKAGE
I.e. just like distinct symbols in different packages have got nothing to do with each other just because they happen to have the same SYMBOL-NAME in Lisp, similarly in XML, two elements with the same local-name but a different namespace are considered distinct.
and here's the local snippet of the xmls that I'm trying to filter for:
[...]
So, there's an attribute with a local-name that matches the value in of-name. Why is this function always returning NIL?
An element with that local-name, right?
Is stp stable enough for production use? It's been a while since it's been updated. I'm new to XML with LISP, so if there's a better documented or easier way to process these documents, happy to take a different route.
I think STP was pretty much finished when it was first written, because it is basically a Common Lisp adaptation of XOM, so the design was clear from the start.
Finally, does anyone know why I need to pass the function the first child? Seem cxml-stp is getting tripped up on the first line of the xml file: <?xml version="1.0" encoding="UTF-8"?> and forcing me to manually grab the second element. Is there a convention or idiom I'm missing?
I see no reason why you would have to call stp:first-child. The example works without that call.
d.