English Idiom in Unix: Directory Recursively

[Thomas A. Russ]

"Pascal J. Bourguignon" <pjb at informatimago.com> writes:

> tar at sevak.isi.edu (Thomas A. Russ) writes:
> >
> > This will only work if there is a backpointer to the parent.
> 
> No, you don't need backpointers; some cases have been mentionned in the
> other answer, but in general:
> 
>     (defun parent (tree node)
>        (if (member node (children tree))
>           tree
>           (some (lambda (child) (parent child node)) (children tree))))
> 
> Yes, the question wasn't about time complexity.

 :-p

Um, this is a recursive function.  Inside PARENT, there is another call
to PARENT.

-- 
Thomas A. Russ,  USC/Information Sciences Institute