title: Racket/Scheme: working with structs
body: <p>I have been given a struct to work with:</p>
  
  <pre><code>(struct Binding (id (value #:mutable)))
  </code></pre>
  
  <p>This struct represents a variable binding such as <code>(set! x 3)</code> where I would expect id = x and value = 3.</p>
  
  <p>How do I create and initialize this struct?  How do I get the values of <code>id</code> and <code>value</code> and to set the value of <code>value</code>?</p>