When CL-Interpol is too big for your needs…

…you can use this port of Perl’s qq to lisp:

(defun |#q-reader| (stream sub-char numarg)
  (declare (ignore sub-char numarg))
  (let ((terminator (read-char stream)))
    (loop for ch = (read-char stream)
          until (eql ch terminator)
          collect ch into chars
          finally (return (coerce chars 'string)))))
 
(set-dispatch-macro-character
    #\# #\q #'|#q-reader|)

More information in Space Station Lambda.

You can find CL-INTERPOL in Edi Weitz’s website.