Re: Extend Outline mode with default visibility state

[Eli Zaretskii <eliz@gnu.org>]

The doc string of outline-default-state "Needs Work":

  (defcustom outline-default-state nil
    "If non-nil, some headings are initially outlined.

  Note that the default state is applied when the major mode is set
  or when the command `outline-apply-default-state' is called
  interactively.

What major mode does this allude to?

  When nil, headings visibility is left unchanged.

Unchanged from what state?

  If equal to `outline-show-all', all text of buffer is shown.

  If equal to `outline-show-only-headings', only headings are shown.

What does "headings" mean here?  Does it mean headings off all the
levels, or just of the top level, or something else?

  If equal to a number, show only headings up to and including the
  corresponding level.  See `outline-default-rules' to customize
  visibility of the subtree at the choosen level.

Is `outline-default-rules' relevant only to that single value of
outline-default-state?

  If equal to a lambda function or function name, this function is
  expected to toggle headings visibility, and will be called after
  the mode is enabled."

This doesn't say whether the function is called with any arguments.

The doc string of outline-default-rules also "Needs Work":

  (defcustom outline-default-rules nil
    "Determines visibility of subtree starting at `outline-default-state' level.

If this is only relevant to a single value of outline-default-state,
the doc string should say so.

  - A lambda function or function name which will be evaluated with
    point at the beginning of the heading and the match data set
    appropriately, the function being expected to toggle the
    heading visibility."

This should tell what arguments, if any, the function is called.
Also, "function ... will be evaluated" is not our style.

Can these issues be fixed, please?

Thanks.