title: Is it possible to redefine PHP constants?
body: <p>Is it possible to redefine class constants (in PHP)?</p>
  
  <p>e.g.</p>
  
  <pre><code>class B {
  const C_ThisIsAConstant = 1;
  }
  
  class A extends B {
   self::C_ThisIsAConstant = 2;
  }
  </code></pre>