title: Single-letter prefix for PHP class constants?
body: <p>I've noticed many (all?) PHP constants have a single-letter prefix, like <code>E_NOTICE</code>, <code>T_STRING</code>, etc.  When defining a set of class constants that work in conjunction with one another, do you prefer to follow similar practice, or do you prefer to be more verbose?</p>
  
  <pre><code>class Foo {
      // let's say 'I' means "input" or some other relevant word
      const I_STRING = 'string';
      const I_INTEGER = 'integer';
      const I_FLOAT = 'float';
  }
  </code></pre>
  
  <p>or </p>
  
  <pre><code>class Bar {
      const INPUT_STRING = 'string';
      const INPUT_INTEGER = 'integer';
      const INPUT_FLOAT = 'float';
  }
  </code></pre>