[Python-Dev] xml.parsers.expat no userdata in callback functions

Guido van Rossum gvanrossum at gmail.com
Sat Aug 13 23:02:54 CEST 2005

> Kristian Benoit wrote:
> > This means one cant parse multiple files at the same time using the same
> > handlers. You cant pass the context current context to the handler, you must
> > base your code on global variables which is not so nice.
"Martin v. Löwis" replied:
> This is not true. You can create multiple parsers, and then can make the
> callback functions bound methods, using self to store parse-specific
> data. There is no need to have extra callback data.

What he said. Kristian's complaint is probably a common misconception
about Python -- not too many languages have unified the concepts of
"bound methods" and "callables" so completely as Python. Every
callable is in a sense a closure (or can be). Nested functions are
other examples.

--Guido van Rossum (home page: http://www.python.org/~guido/)

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