title: Variables versus constants versus associative arrays in PHP
body: <p>I'm working on a small project, and need to implement internationalization support somehow. I am thinking along the lines of using constants to define a lot of symbols for text in one file, which could be included subsequently. However, I'm not sure if using variables is faster, or if I can get away with using associative arrays without too much of a performance hit. </p>
  
  <p>What's better for defining constant values in PHP, performance-wise -- constants defined using <code>define("FOO", "...")</code>, or simple variables like <code>$foo = "..."</code>, or associative arrays like <code>$symbols["FOO"]</code>?</p>