lua_Reader, how to make one

["Wesley Smith" <wesley.hoke@...>]

Hi List,
I want to make nice error messages like luac in my app, so I need to
use lua_load directly.  I see that a lua_Reader is required and
roughly understand what a lua_Reader is supposed to do, but I have no
idea how to actually make one.  I haven't found any decent examples
googling or on the wiki.  I don't want to do anything more than
luaL_dofile except associate a filename with the error messages.  I've
looked at luac, but it seems to do things more indirectly than what
I'm after using lua_cpcall.  Anyone have any examples?

thanks,
wes