# File: sgmllib-example-1.py

import sgmllib
import string

class FoundTitle(Exception):
    pass

class ExtractTitle(sgmllib.SGMLParser):

    def __init__(self, verbose=0):
        sgmllib.SGMLParser.__init__(self, verbose)
        self.title = self.data = None

    def handle_data(self, data):
        if self.data is not None:
            self.data.append(data)

    def start_title(self, attrs):
        self.data = []

    def end_title(self):
        self.title = string.join(self.data, "")
        raise FoundTitle # abort parsing!

def extract(file):
    # extract title from an HTML/SGML stream
    p = ExtractTitle()
    try:
        while 1:
            # read small chunks
            s = file.read(512)
            if not s:
                break
            p.feed(s)
        p.close()
    except FoundTitle:
        return p.title
    return None

#
# try it out

print "html", "=>", extract(open("samples/sample.htm"))
print "sgml", "=>", extract(open("samples/sample.sgm"))

## html => A Title.
## sgml => Quotations