Steven D'Aprano wrote:
On Sun, 05 Jul 2009 01:58:13 -0700, Paul Rubin wrote:
Steven D'Aprano <st...@remove-this-cybersource.com.au> writes:
Okay, we get it. Parsing HTML 5 is a bitch. What's your point? I don't
see how a case statement would help you here: you're not dispatching on
a value, but running through a series of tests until one passes.
A case statement switch(x):... into a bunch of constant case labels
would be able to use x as an index into a jump vector, and/or do an
unrolled logarithmic (bisection-like) search through the tests, instead
of a linear search.
Yes, I'm aware of that, but that's not what John's code is doing -- he's
doing a series of if expr ... elif expr tests. I don't think a case
statement can do much to optimize that.
(I didn't write that code; it's from "http://code.google.com/p/html5lib/";,
which is a general purpose HTML 5 parser written in Python. It's compatible
with ElementTree and/or BeautifulSoup. I currently use a modified
BeautifulSoup for parsing real-world HTML in a small-scale crawler, and
I'm looking at this as an HTML 5 compatible replacement.)
John Nagle
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