ghlight">\(y\)</span> is a program, and running
<span class="math notranslate nohighlight">\(y\)</span> with R1 empty results in <span class="math notranslate nohighlight">\(x\)</span> back in R1 and all
other registers empty.</p></li>
</ol>
<p>In the notation from <a class="reference internal" href="functions.html"><span class="doc std std-doc">a little later</span></a>, we have</p>
<div class="math notranslate nohighlight">
\[
[\![ [\![ \writeprog]\!](x)]\!](\ ) = x
\]</div>
<p>Here is a table for <span c