There are some idioms in Lua that you might recognize from Python or Ruby. I have seen this one in Perl and the Bourne shell, as well. ffi = ffi or require("

There are some idioms in Lua that you might recognize from Python or Ruby. I have seen this one in Perl and the Bourne shell, as well. ffi = ffi or require("ffi") If the ffi expression evaluates to something that is not nil, we keep the previous value of ffi. The assignment becomes a no-op. If it evaluates to a nil, we initialize it by calling require().