Question

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How to remove nested parentheses in LISP

This is my second quick-and-silly question about LISP, but I am kind of stuck. I need to access all the nodes in a list with several levels. I need something like:

>> (get-symbols '(A (B (C D) E )))
(A B C D E)

I don’t care about the order. How would you do that? I prefer code intuitivity rather than efficency.

Thanks

Answer 1

From OnLisp:

(defun flatten (tree)
  (if (atom tree)
      (mklist tree)
    (nconc (flatten (car tree))
       (if (cdr tree) (flatten (cdr tree))))))