 The default value for <span class="arg-name">prefix</span> is <code>"BIGNUMBER:"</code>.</dt>
  <dd><code class="other-name">rational-approximation</code></dd>
  <dt>Parse the number token into parts, read them as integers, and combine the integers using only rational operations.  Use the resulting rational number in place of float.  (E. g., <code class="json-literal">2.065e444</code> would be converted to the value of the expression <code>(* (+ 2 (* 65 (expt 10 -3))) (expt 10 444))</code>.)</dt>
  <dd><co