Path: csiph.com!usenet.pasdenom.info!weretis.net!feeder1.news.weretis.net!news.swapon.de!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail
From: Neil Cerutti <neilc@norwich.edu>
Newsgroups: comp.lang.python
Subject: sax.handler.Contenthandler.__init__
Date: 30 Aug 2013 17:20:16 GMT
Organization: Norwich University
Lines: 24
Message-ID: <b8c2igFiupsU1@mid.individual.net>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
X-Trace: individual.net obpi+skXP8Ewn5qBkdsalwEPrvyNflJje4AZ4mE/1ObZ9egqZn
Cancel-Lock: sha1:uG4VUBJRdfnrOo1bBaHaJhM1yFk=
User-Agent: slrn/0.9.9p1/mm/ao (Win32)
Xref: csiph.com comp.lang.python:53305

This code is from The Python Cookbook, 2nd edition, 12.2 Counting
Tags in a Document:

from xml.sax.handler import ContentHandler
import xml.sax
class countHandler(ContentHandler):
    def __init__(self):
        self.tags={}
    def startElement(self, name, attr):
        self.tags[name] = 1 + self.tags.get(name, 0)

Isn't overriding __init__ a risky thing to do? The docs don't
mention it as a method I should override, and also don't define
what's in there or if I'd need to call the base class __init__.
Moreover, startDocument is provided for parser setup.

As it happens, ContentHandler.__init__ isn't empty, so the above
code could fail if the parser isn't prepared for _locator to be
undefined.

Is the above code is an acceptable idiom?

-- 
Neil Cerutti