[Python-Dev] Difference in RE between 3.2 and 3.3 (or Aaron Swartz memorial)
mcepl at redhat.com
Thu Mar 7 11:08:40 CET 2013
On 2013-03-06, 18:34 GMT, Victor Stinner wrote:
> In short, Unicode was rewritten in Python 3.3 for the PEP 393. It's
> not surprising that minor details like singleton differ. You should
> not use "is" to compare strings in Python, or your program will fail
> on other Python implementations (like PyPy, IronPython, or Jython) or
> even on a different CPython version.
I am sorry, I don't understand what you are saying. Even though
this has been changed to
the tests still fail.
But, Amaury is right: the function doesn't make much sense.
when I have “fixed it” from
"""Return true if the line does only consist of whitespace characters."""
for c in line:
if c is not ' ' and c is not ' ':
return c is ' '
"""Return true if the line does only consist of whitespace
for c in line:
if c != ' ' and c != ' ':
return c == ' '
tests on ALL versions of Python are suddenly failing ...
Curiouser and curiouser! At least, I seem to have the point,
where things are breaking, but I have to admit that condition
really doesn’t make any sense to me.
> Anyway, you spotted a missed optimization: it's now "fixed" in
> Python 3.3 and 3.4 by the following commits.
Well, whatever is the problem, it is not fixed in python 3.3.0
(as you can see in
https://travis-ci.org/mcepl/html2text/builds/4969045) as I can
see on my computer. Actually, good news is that it seems to be
fixed in the master branch of cpython (or the tip, as they say in
the Mercurial world).
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