Re: Protecting global variables

[Enrico Colombini <erix@...>]

Peter, assuming I understood correctly what you want to do, you could 
also consider a sandbox approach, rather than filtering _G access:

- Create a table that will be your user's global table. You could start 
with an empty table, or include some globals:

  userGlobal = { print=print, string=string, myvar=myvar }

- Attach a metatable to handle your special variables (as you already did).

- Execute user's code with that table as environment (using sefenv() in 
Lua 5.1 or setting _ENV in Lua 5.2).

--
  Enrico