yielding troubles

["Matthew Harmon" <matt@...>]

Well? I?m a Lua addict.  Our game engine is more and more becoming just a
set of functions that are called from Lua!

Anyway, I want to have one Lua program call another and execute in the same
thread. For all practical purposes this is essentially like #include-ing
code from another file.  In the child script, I?d like to be able to issue a
yield, but it doesn?t seem to be working.  This should give the idea in
pseudo code:

  -- MainScript.lua
  RunScriptInCurrentThread(?LoadKeyConfiguration.lua?);
  RunScriptInCurrentThread(?DoStartupStuff.lua?);
  RunScriptInCurrentThread(?OpeningSlideshow.lua?);
  PrintMessage(?Well, that slideshow lasted roughly 4 seconds!?);

  -- OpeningSlideshow.lua
  ShowSlide(?xxx?)
  ?yield? for 2 seconds
  ShowSlide(?xxx?)
  ?yield? for 2 more seconds

Is this because the yield is essentially nested two-deep in C calls?  Any
help, thoughts, suggestions would be most appreciated.