[Python-Dev] ElementTree in stdlib (original) (raw)

Jason Orendorff jason.orendorff at gmail.com
Wed Dec 14 17:39:55 CET 2005

Guido van Rossum wrote:

On 12/13/05, Walter Dörwald <walter at livinglogic.de> wrote: > Having to define classes that conform to a certain API and registering > instances of those classes as callbacks with the parser doesn't look > that pythonic to me. An iterator API seems much more pythonic.

Perhaps. Although the SAX API lets you leave a callback undefined if you don't have a need to handle those events; that's a bit trickier to do with an iterator.

Well, suppose you want to dump the text of a document.

for e in iterparse(filename):
    if e.isText():
        out.write(e.data)

Not tricky.

> Also the different callbacks have different signatures.

True. With SAX I always have to look up the signatures. The iterator yields Node-like objects in document order. I don't have to remember signatures.

But the biggest advantage of an iterator-based API would be: when you hit an element, you can easily pass control to a function that knows how to parse that particular element. parsePlay() can call parseAct(), which can call parseScene(). To do anything like that with SAX, you have to write a bunch of dispatch code.

-j

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