# File: xmllib-example-2.py

import xmllib
import string, sys

STYLESHEET = {
    # each element can contribute one or more style elements
    "quotation": {"style": "italic"},
    "lang": {"weight": "bold"},
    "name": {"weight": "medium"},
}

class Parser(xmllib.XMLParser):
    # a simple styling engine

    def __init__(self, renderer):
        xmllib.XMLParser.__init__(self)
        self.__data = []
        self.__tags = []
        self.__renderer = renderer

    def load(self, file):
        while 1:
            s = file.read(8192)
            if not s:
                break
            self.feed(s)
        self.close()

    def handle_data(self, data):
        self.__data.append(data)

    def unknown_starttag(self, tag, attrs):
        if self.__data:
            text = string.join(self.__data, "")
            self.__renderer.text(self.__tags, text)
        self.__tags.append(tag)
        self.__data = []

    def unknown_endtag(self, tag):
        self.__tags.pop()
        if self.__data:
            text = string.join(self.__data, "")
            self.__renderer.text(self.__tags, text)
        self.__data = []

class DumbRenderer:

    def __init__(self):
        self.cache = {}

    def text(self, tags, text):
        # render text in the style given by the tag stack
        tags = tuple(tags)
        style = self.cache.get(tags)
        if style is None:
            # figure out a combined style
            style = {}
            for tag in tags:
                s = STYLESHEET.get(tag)
                if s:
                    style.update(s)
            self.cache[tags] = style # update cache
        # write to standard output
        sys.stdout.write("%s =>\n" % style)
        sys.stdout.write("  " + repr(text) + "\n")

#
# try it out

r = DumbRenderer()
c = Parser(r)
c.load(open("samples/sample.xml"))

## $ python xmllib-example-2.py
## {'style': 'italic'} =>
##   'I\'ve had a lot of developers come up to me and\012say,
##   "I haven\'t had this much fun in a long time. It sure
##   beats\012writing '
## {'style': 'italic', 'weight': 'bold'} =>
##   'Cobol'
## {'style': 'italic'} =>
##   '" -- '
## {'style': 'italic', 'weight': 'medium'} =>
##   'James Gosling'
## {'style': 'italic'} =>
##   ', on\012'
## {'weight': 'bold'} =>
##   'Java'
## {'style': 'italic'} =>
##   '.'