Neil Cerutti wrote:
> 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
> --
I think this is a bad idea unless you want to avoid the parent
class __init__ specifically (in which case a comment stating
why is mandatory). I do not like that this recipe shows behavior
that might be fine in this instance, but is not a good general
practice.
def __init__(self):
super(ContentHandler, self).__init__()
#OR ContentHandler.__init__(self)
self.tags={}
I personally think the super() line is better of the two options.
~Ramit
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