title: how to assign lua variable by reference
body: <p>How can I assign a variable by reference in Lua to another one?  </p>
  
  <p>For example:  want to do equivalent of "a = b" where a will then be a pointer to b</p>
  
  <p>Background:
  have a case where I have effectively something like this:</p>
  
  <pre><code>local a,b,c,d,e,f,g   -- lots of variables
  
  if answer == 1 then
    -- do stuff with a
  elsif answer == 1 then
    -- do stuff with b
  .
  .
  .
  </code></pre>
  
  <p>PS. For example in the below it appears apparent the b=a is by value.  NOTE: I'm using Corona SDK.</p>
  
  <pre><code>a = 1
  b = a
  a = 2
  print ("a/b:", a, b)
  
  -- OUTPUT: a/b: 2   1
  </code></pre>