That is interesting.  I&#x27;ve always considered lisp in terms of denotational semantics.  In fact, I wrote a toy lisp in which the complete grammar was basically<p><pre><code>    list -&gt; ({symbol | number | string | list}*)
</code></pre>
and then it was up to the interpreter to decide the meaning of special forms. (I say &quot;basically&quot; because there was also desugaring of &#x27;(...) to (quote ...)).