Re: Modules with standalone main program

[albertmcchan <albertmcchan@...>]

I now know why require "mod" set package.loaded.mod to some userdata
the userdata "sentinel" is used to check for errors during require,
and provide a default true if mod.lua does not return anything.

we can use sentinel to test mod.lua currently being required:

patch: in loadlib.c luaopen_package()

< lua_pushlightuserdata(L, sentinel);
< lua_setfield(L, -2, "loading");

with above 2 lines patch, we can now do this:

if package.loaded.mod == package.loading then 
    return mod_func
end

-- code below for running stand-alone