Reader macro that implements Scheme's SRFI 62 S-expression comments in Common Lisp

s-expression-comments.lisp

;;;; Reader macro that implements Scheme's SRFI 62 S-expression comments in Common Lisp.
;;;; SRFI 62: https://srfi.schemers.org/srfi-62/srfi-62.html
;;;; Adapted from: https://stackoverflow.com/questions/69248229/reads-recursive-p-argument-when-used-inside-a-reader-macro

(eval-when (:compile-toplevel :load-toplevel :execute)
  (set-dispatch-macro-character #\# #\;
    (lambda (stream char n)
      (declare (ignore char))
      (when n
        (error "No number allowed between # and ;"))
      (read stream t nil t)  ; Discard the S-expression.
      (values))))