title: Which lang packet is proper for SICP in Dr.Racket?
body: <p>I'm trying with SICP and I got some code.
  So I started with:</p>
  
  <pre><code>#lang scheme
  (word 'comp 'uter)
  </code></pre>
  
  <p>Returned error: Function (word) undefined.</p>
  
  <p>Even if I tried to copy this into IDE(Run):</p>
  
  <pre><code>(define word?
    (let ((number? number?)
          (symbol? symbol?)
          (string? string?))
      (lambda (x)
        (or (symbol? x) (number? x) (string? x)))))
  </code></pre>
  
  <p>Still the same.</p>
  
  <p>I think it may be certain problem with version of language or else.</p>
  
  <hr>
  
  <p>Above are from "Simply Scheme" and when I introduce code exactly in SICP:</p>
  
  <pre><code>(define (sqrt x)
      (sqrt-iter 1.0 x))
  </code></pre>
  
  <p>IDE returned <code>sqrt-iter</code> undefined. The code can be found in chapter one: <a href="http://mitpress.mit.edu/sicp/code/index.html">http://mitpress.mit.edu/sicp/code/index.html</a></p>