Changes that caught my eye in Python 3.2

Python 3.2 was released a few days ago. Reading the What’s New document, some of the stuff that caught my eye…

argparse is a new command-line option parsing module that replaces optparse. I found optparse, now deprecated, a pain to use—argparse looks a lot better. argparse can be used in older programs today with a third-party module (E.g. argparse Debian package). I actively avoided adding command-line parsing to my applications because optparse was such a pain—something now much less of a problem.

The new concurrent.futures module seems to be a port of Java’s java.util.concurrent package. I haven’t looked into it yet, but with the GIL, how many people really care about Python threads? The simple examples given can easily be done with Python’s multiprocessing module, for both processes and threads, though without the Java paradigm. The threading module also has a new threading.Barrier class.

WSGI for Python 3 appears to be finalized. I’m looking forward to finally porting my WSGI web applications to Python 3. The email module also received the same makeover that WSGI needed for Python 3.

ElementTree has been updated to v1.3. Not that I care—lxml’s namespace handling is much better (which is to say, it’s just terrible as opposed to near unusable, as is with pure ElementTree).

Quite possibly the most badass addition to Python 3.2: the functools.lru_cache decorator. I use this pattern all the time, but have never gotten around to making it a generic class or decorator I could reuse across applications. With Python 3.2, I no longer need to. The idea: decorate a slow-performing function (where it makes sense) with functools.lru_cache, and Python will instantly and easily memoize the return values of that function making subsequent calls to the function faster.

html.escape() is a simple function that escapes HTML markup for you with the appropriate HTML/XML entities (I forget how I used to do this usually; something in one of the CGI utils, I think? Or maybe stuff in my template engine…).

This is just from a quick reading of the release notes—it’s very likely I missed something. What’d I miss? And what do you like that’s new in Python 3.2?

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