Firing SAX events from a DOM tree in 4Suite

One nice thing about the briskly-moving 4Suite documentation project is that it is shining a clear light on places where we need to make the APIs more versatile. Adding convenience parse functions was one earlier result.

Saxlette has the ability to walk a Domlette tree, firing off events to a handler as if from a source document parse. This ability used to be too well, hidden, though, and I made an API addition to make it more readily available. This is the new Ft.Xml.Domlette.SaxWalker. The following example should show how easy it is to use:

from Ft.Xml.Domlette import SaxWalker
from Ft.Xml import Parse

XML = ""

class element_counter:
    def startDocument(self):
        self.ecount = 0

    def startElementNS(self, name, qname, attribs):
        self.ecount += 1

#First get a Domlette document node
doc = Parse(XML)
#Then SAX "parse" it
parser = SaxWalker(doc)
handler = element_counter()
#You can set any properties or features, or do whatever
#you would to a regular SAX2 parser instance here
parser.parse() #called without any argument
print "Elements counted:", handler.ecount

Again Saxlette and Domlette are fully implemented in C, so you get great performance from the SaxWalker.

[Uche Ogbuji]

via Copia