&gt; Traditional hash tables are imperative data structures, and Lisp code (or Scheme code, at least) typically does not use them because of this.<p>I don&#x27;t understand that.<p>&gt; Association lists, which can be represented as literals, are persistent and provider faster lookup, despite being {snip}<p>Those look like like they could be useful, but I don&#x27;t see how they can replace hashmaps --- for one thing, they allow duplicate &quot;keys&quot; (the first element of each pair).<p>I&#x27;d use a lisp, and don&#x27;t mind the lisp&#x2F;parens syntax, but to be useful for me it must provide easy access to and use of hashmaps and sets.