differentiate cons & list

[dericbytes]

I want to know when an item is a cons and when it is a list

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(consp (cons 1 1))

> t

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(listp (cons 1 1))

>t

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(consp (list 1 1))

>t

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(listp (list 1 1))

>t

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(nth 1 (cons 1 1))

> error not a list

[Goheeca]

What about this:

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(defun true-list-p (list)
  (cond ((null list) t)
        ((consp list) (true-list-p (cdr list)))
        (t nil)))