Why isn't Lua 5.2's debug hook function called with lua_callk()?

[mitchell <code@...>]

Hi,

I was using Lua 5.1 + LuaCoco to yield from a debug hook function and that 
was working fine. I was hoping that Lua 5.2, which incorporates some of 
LuaCoco's functionality, would allow this natively but looking at the code 
in ldblib.c:271 (in hookf) shows lua_call() being used instead of 
lua_callk(). Therefore I am getting the 'attemp to yield across C-call 
boundary' errors. Is there a reason for not using lua_callk()?

Thanks,
mitchell