I wanted to find out if Namespace supported lookup by subscripting (args['someopt']), but the docs are silent on what Namespace is.  (The answer, by the way, appears to be "no"; there is a feature request for this in issue 8979).

That's right, it doesn't support subscripting. The docs are silent on what namespace is mainly because I don't want to commit to anything other than an object with attributes. But that could be made clearer in the docs.

New changeset 423b50086b67 by Steven Bethard in branch '3.2':
Issue #8982: Improve the documentation for the argparse Namespace object.
http://hg.python.org/cpython/rev/423b50086b67

New changeset d832756a82d9 by Steven Bethard in branch 'default':
Issue #8982: Improve the documentation for the argparse Namespace object. (Merge from 3.2.)
http://hg.python.org/cpython/rev/d832756a82d9

New changeset fe72160ea2a3 by Steven Bethard in branch '2.7':
Issue #8982: Improve the documentation for the argparse Namespace object. (Merge from 3.2.)
http://hg.python.org/cpython/rev/fe72160ea2a3

I fixed the docs here so that they're clearer about what the Namespace object is, and also so that they mention the `vars` approach if you want dict-style access.

Attached patch adds a link target for :class:`Namespace` (already used in the docs) and adds a reference to it from for the first mentions of “namespace object”.

Use “hg import blah.diff” (after “hg up 3.2”) to get the patch in the repo directly (with checkin message and my committer name) or usual patch(1) if you want to make amendments.

Patch refreshed.  If I get no negative feedback, I’ll commit it next week.

New changeset 939631c6bc6f by Éric Araujo in branch '3.2':
Add a link target for argparse.Namespace (#8982)
http://hg.python.org/cpython/rev/939631c6bc6f

New changeset 01722022f88d by Éric Araujo in branch '2.7':
Add a link target for argparse.Namespace (#8982)
http://hg.python.org/cpython/rev/01722022f88d