ions
      like <code class="computeroutput"><span class="identifier">abs</span></code> or <code class="computeroutput"><span class="identifier">sin</span></code>
      with <code class="computeroutput"><span class="identifier">number</span></code> arguments. This
      means that an expression such as:
    </p>
<pre class="programlisting"><span class="identifier">y</span> <span class="special">=</span> <span class="identifier">abs</span><span class="special">(</span><span class="identifier">x</span><span c