bug#55900: [PATCH] Hierarchy – Defer the Computation of Children

[Eli Zaretskii <eliz@gnu.org>]

> From: "Wamm K. D." <jaft.r@outlook.com>
> Date: Sat, 11 Jun 2022 01:52:13 -0500
> 
> Pretty much as the subject describes; this should allow for users to
> lazily load hierarchy branches when loading everything at once would
> otherwise be too consuming, up-front (or if dealing with an infinite
> tree).

Thanks.

> * lisp/emacs-lisp/hierarchy.el (hierarchy-add-tree) (hierarchy-add-trees):
> Add parameter 'delay-children-p'.

Please use our style of commit log messages.  The above should be

* lisp/emacs-lisp/hierarchy.el (hierarchy-add-tree)
(hierarchy-add-trees): Add parameter 'delay-children-p'.

> +(defun hierarchy--create-delayed-tree-widget (elem labelfn indent fn)
> +  "Return a list of tree-widgets for a hierarchy created from the childrenfn.

The first line of the doc string should ideally mention the
arguments.  This one doesn't, and it also seems to misname one
argument: it's FN, not childrenfn, right?

Can this be improved?

Can you add some tests of this new functionality?

Also, I think this warrants a NEWS entry to describe the new feature.