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.
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.