How to access url query parameters in Clack, Lucerne or Caveman

from blog Lisp journey, | ↗ original
edit: I found Snooze (by Sly and Yasnippet’s author) easier and cleaner in this regard. It also has built-in settings to choose where to catch errors: with Slime’s debugger, with a full stacktrace in the browser or displaying a custom error page. If you’re using Lucerne don’t search more like I did, its with-params macro works with url query...