Some of that looks like C-language, some of that looks like Lua, and I'm not sure what you're asking, but I'll try to help out. Consider the following Lua code.
local A = { a=1, b=2 } function Sum( arg )
return arg.a + arg.b end local c = Sum( arg ) print( "c = " .. c )
Assuming I didn't make a mistake, that should print "3". Notice that variables holding a table value are just pointers to such values. I don't believe the same is true for variables holding integral or string values, but I don't know much about Lua internals.