You are right that they could use a carefully crafted API to work around the problems. Its also true that yields across C were added in 5.2 but you need to code

You are right that they could use a carefully crafted API to work around the problems. Its also true that yields across C were added in 5.2 but you need to code the C functions in continuation-passing-style using a special API to take advantage of that. http://www.lua.org/manual/5.2/manual.html#4.7 http://www.lua.org/manual/5.2/manual.html#4.7