title: $parse vs $eval ? which one is best practice?
body: <p>I know that <code>$parse</code> and <code>$eval</code> both operate on Angular expressions.then why Angular team created these two ?</p>
  
  <p>I checked in angular library, <code>$eval</code> is defined like that:</p>
  
  <pre><code>$eval: function(expr, locals) {
          return $parse(expr)(this, locals);
        }
  </code></pre>
  
  <p>so what is difference between :</p>
  
  <pre><code>$parse(expr)(context, locals);
  </code></pre>
  
  <p>and </p>
  
  <pre><code>$eval: function(expr, locals) {
          return $parse(expr)(this, locals);
        }
  </code></pre>
  
  <p>I want to know which one is best practice ? and when to use these two ?</p>