title: Lua pattern matching for email address
body: <p>I having the following code: </p>
  
  <pre><code>if not (email:match("[A-Za-z0-9%.]+@[%a%d]+%.[%a%d]+")) then
       print(false)
  end
  </code></pre>
  
  <p>It doesn't currently catch </p>
  
  <pre><code> "test@yahoo,ca"  or "test@test1.test2,com"
  </code></pre>
  
  <p>as an error. </p>
  
  <p>I thought by limiting the input to <code>%a</code> - characters and <code>%d</code> - digits, I would by default catch any punctuation, including commas.</p>
  
  <p>But I guess I'm wrong.  Or there's something else that I'm just not seeing. 
  A second pair of eyes would be appreciated. </p>