invoking objective-c messages and invoking SiO2 API calls from obj-c

Wondering if there were any samples of how to do this?
* Invoking objective-c from the SiO2 engine (lua or otherwise)
* Sinking a game event in Obj-C
* invoking API calls in SiO2 from obj-c (i.e.: on-screen keyboard input or startup from from navigation event)

josgraha wrote:
* Invoking objective-c from the SiO2 engine (lua or otherwise)

LuaCore might be of use

http://gusmueller.com/lua/

You can use obj-c anywhere or anytime you want.