Gruling XML library i wrote.

gistfile1.py

"""
Example user case:

define rules:

rules = [
    ("library_images / image id / init_from / *", image),
    ("library_effects / effect id / profile_COMMON / newparam sid / sampler2D / source / *", effect),
    ("library_materials / material id name / instance_effect url", material),
    
    ("node id name / ...", node),  
    ("node id / translate sid / *", ch),
    ("node id / rotate sid / *", ch),
    ("node id / scale sid / *", ch),
    ("node id / instance_geometry url", geomurl),
    ("node id / instance_geometry / bind_material / technique_common / instance_material target", mat),

    ("library_geometries / geometry id", geometry),
    ("library_geometries / geometry id / mesh / source id / float_array / *", float_array),
    ("library_geometries / geometry id / mesh / vertices id / input semantic source", vertices),
    ("library_geometries / geometry id / mesh / polylist / input offset semantic source", polylist_input),
    ("library_geometries / geometry id / mesh / polylist / vcount / *", polylist_vcount),
    ("library_geometries / geometry id / mesh / polylist / p / *", polylist_p),
]

parse the file

GrulingXML(rules, in_file)

"""

import xml.sax
 
class Rule:
    def __init__(self, text, fn):
        self.path = []
        for r in text.split("/"):
            r = r.strip()
            l = r.split(" ")
            self.path.append(l)
        self.fn = fn
        self.post =  self.path[-1][0] == "*"
        
    def match(self, path, text):
        n = -1
        args = []
        for r in reversed(self.path):
            if r[0] == "*":
                args.append(text)
                continue
            if r[0] == "...":
                args.append(path)
                continue
            if path[n][0] == r[0]:
                for a in reversed(r[1:]):
                    try:
                        r = path[n][1][a]
                    except:
                        r = None
                    args.append(r)
                n -= 1
            else:
                return
        args.reverse()
        self.fn(*args)
 
class GrulingXML(xml.sax.ContentHandler):
    def __init__(self, rules, source):
        self.rules = []
        for rule in rules:
            self.rules.append(Rule(*rule))
        xml.sax.ContentHandler.__init__(self)
        source = open(source)
        self.path = []
        self.content = ""
        xml.sax.parse(source, self)
        
    def startElement(self, name, attrs):
        self.path.append([name, attrs])
        self.content = ""
        for rule in self.rules:
            if not rule.post:
                rule.match(self.path, self.content)
    
    def endElement(self, name):
        for rule in self.rules:
            if rule.post:
                rule.match(self.path, self.content)
        self.path.pop()
        pass
 
    def characters(self, content):
        self.content += content
        pass