Getting all user defined global variables from lua

Question

I've been trying to find the solution but I can't find any examples. So if the lua script is this:

myGlobal1 = "Global 1"
myGlobal2 = 2

function test()
  local l1=0
  print (myGlobal1,myGlobal2,l1)
end

test()

How can I find all global variables defined by the user in the script from in c++? I am building a level editor and I want the user to be able to define public global variables in the script and have them show up in the editor so they can change the variables.