title: Change printing of numbers in DrRacket REPL
body: <p>In DrRacket with <code>#lang racket</code>, I can enter numbers in binary format like this:</p>
  
  <pre><code>&gt; #b10.1
  2.5
  </code></pre>
  
  <p>and I can print numbers in binary format like this:</p>
  
  <pre><code>&gt; (printf (~r 2.5 #:base 2))
  10.1
  </code></pre>
  
  <p>How can I make numbers print in binary automatically in the REPL, like this:</p>
  
  <pre><code>&gt; #b10.1
  #b10.1
  </code></pre>
  
  <p>or maybe this:</p>
  
  <pre><code>&gt; #b10.1
  10.1
  </code></pre>
  
  <p>?</p>
  
  <p>Note that I am not just trying to print decimal numbers with "#b" appended.  When  I plot numbers, for example, <code>#b10.1</code> should behave like 2.5.</p>
  
  <p>If there is no configuration setting that is designed for this purpose, then maybe it would require replacing the P in the REPL, i.e. replacing the printing part of the read-eval-print-loop.</p>