Strangely enough, I did not really answer your question, I'm sorry.
In order to get a list of namespaces having a given access level one should use, I believe, Language::getNamespaces() in an obvious way, in combination with what I wrote before.
-- Petr
2006/7/14, Petr Andreyev gulliput@gmail.com:
Hi Dan,
Using your NamespacePermissions extension, is there a way to retrieve a list of namespaces to which a user has RO or RW access?
One can know if a user is in one of the autocreated groups: ex. in_array( "ns{$ns_title}RO", $user->getGroups() );
It is possible also to know if a user can do a particular action with an article in a namespace: e.g. $user->isAllowed( "ns100_read" ). This is a more adequate way to obtain access permissions for a given namespace, since the access level is determined by permissions; autogroups just contain most usable sets of permissions.
Petr