[______-_-______]

Big fan of your work, Raph.

One small typo:

> {anonymous function of type FnMut(u32) -> ()}

It looks like the param type should be `&mut u32`. And in that simple case the whole thing could probably just be `fn(&mut u32)` since the closure doesn't capture any locals.

[raphlinus]

Heh yes, somebody else caught that. I think the current state is ok. This closure won't capture any locals, but in general closures in the view tree will. I'll take a PR if you think it should be improved further :)