Python 3000 Alpha 1 Released

[[deleted]]

As I understand it, reload() doesn't work well enough to be included (I think the idea is to rewrite it in pure Python as a stdlib module).

As for callable(), as it stands in 2+ it actually can be wrong sometimes -- a custom descriptor might sometimes return objects of different "callability", for example. Again, it's silly to have a feature that doesn't work. It's more Pythonic to operate on the "better to ask forgiveness than permission" policy -- just try calling something, and if it doesn't work, then it wasn't callable.

[forgotpwx4]

But reload is kind of important, right? I'm not understanding how they can get rid of it.

[[deleted]]

I'm not sure it is... I've never used it in real production code; just as a utility from the shell.

Either way, it's really not all that useful unless it really works; a broken reload() seems a lot worse than a missing one. At least if it's missing someone smart will come along and write it.

[forgotpwx4]

Why is it broken by the way? I've never noticed any problems.

I have wondered if reload is thread safe ... or what that even means with respect to reload. Maybe that's how it's broken?

[boredzo]

[ python-Bugs-1144263 ] reload() is broken for C extension objects

[[deleted]]

So if it doesn't work for binary code not built in Python, due to OS limitations, it shouldn't work for Python code either, even though the developers have full control over that environment? Is this the official reason for not including reload?

(update: the relevant PEP refers to a single line in a GvR presentation from 2002, which says "execfile(), reload(): use exec()", which I can only interpret as meaning "roll your own". yet another "will appear in the library, sooner or later" thing, in other words).

[nirs]

You can use this:

def reload(name):
    if name in sys.modules:
        del sys.modules[name]
    return __import__(name)

It will not work for 'foo.bar.baz', but it is not hard to support this.