&gt; there is a reason that C is the foundation of computing rather than Lisp. I don&#x27;t think anybody really thinks otherwise anymore<p>I must not be anybody, then, because I think that Lisp provides a wonderful notation for thinking about symbolic computation which will last for millennia while C is … a successful programming language of the late 20th century.<p>&gt;  I don&#x27;t know how you even write a hash table based on cons cells rather than O(1) indexing.<p>A cons cell is just a double-pointer.  You can write a hash table using conses just as easily as you would using pointers (note, I&#x27;m not saying that&#x27;d be efficient, which is why Lisp offers arrays as well as conses).