On to my question. The global.* prefix to define wiki-wide attributes
and settings is very useful. Have you thought of a child.* prefix that
applies its settings to the 'children' of the current page, overriding
any global.* settings that are in force.

I realise this is a bit complicated as a wiki is not a tree, so a page
could have several parents with conflicting child.* settings. But most
wikis do have regions within them that are organised in a tree-like
manner, where this facility would be useful. One way of getting around
the difficulty of confllicting parents is by a rule that says the
"nearest" parent (fewest links away) wins.

To find all child.* attributes which may affect a page it would be
necessary to find and look at all parents, grandparents, ... of this
page. And this must be done for all pages.

The information may be cached, but this cache must then be invalidated
properly if a link or a child.* attribute on a page is added or removed
so the cache must be either thrown away entirely or parts of it must be
selected for deletion very carefully.