bug#33309: Add flatten-list?

[Stephen Berman]

On Mon, 10 Dec 2018 17:17:21 -0600 Alex Branham <alex.branham@gmail.com> wrote:

> +(defun flatten-tree (tree)
> +  "Take TREE and \"flatten\" it.
> +This always returns a list containing all the elements of TREE.

Aren't the elements of a tree all its nodes, both terminal and
non-terminal?  If so, then the doc string should say flatten-tree
returns all terminal nodes, or leaves, of TREE, shouldn't it?

Steve Berman