Re: the actions of the spacebar differ in GNU Emacs info [bad] and command line info [good]

[Eli Zaretskii]

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> From: "Dan Jacobson" <jidanni@kimo.FiXcomTHiS.tw>
> Newsgroups: gnu.emacs.bug
> Date: Thu, 21 Dec 2000 00:43:52 +0800
>
> You page down with spacebar. you finally get to the end and then we
> see you are taken to the top menu item on the final screenful. I want
> to be taken to the top menu item of the entire page, not just the last
> screenful.

I made such a change for the next version of Emacs.

> Indeed what I want from Emacs Towers is hitting the spacebar be the
> same as flipping pages in a paper manual, it is in command line info,
> but broke in GNU Emacs info, and there are an amazing amount of
> functions that would need to be fixed if you look at the .el's, for
> such a simple request, so a few more lines added to one of these
> 'advice' calls might be easier.

I managed to get what you wanted with a simple change in a single
function (I also added a defcustom, for people who prefer the previous
behavior; note that the default is still the old behavior):

Index: lisp/info.el
===================================================================
RCS file: /cvs/emacs/lisp/info.el,v
retrieving revision 1.248
retrieving revision 1.249
diff -c -r1.248 -r1.249
*** lisp/info.el        2000/11/19 22:10:52     1.248
--- lisp/info.el        2000/12/04 16:36:44     1.249
***************
*** 126,131 ****
--- 126,144 ----
    :type '(repeat directory)
    :group 'info)
  
+ (defcustom Info-scroll-prefer-subnodes t
+   "*If non-nil, \\<Info-mode-map>\\[Info-scroll-up] in a menu visits subnodes.
+ If this is non-nil, and you scroll far enough in a node that its menu
+ appears on the screen, the next \\<Info-mode-map>\\[Info-scroll-up]
+ moves to a subnode indicated by the following menu item.  This means
+ that you visit a subnode before getting to the end of the menu.
+ 
+ Setting this option to nil results in behavior similar to the stand-alone
+ Info reader program, which visits the first subnode from the menu only
+ when you hit the end of the current node."
+   :type 'boolean
+   :group 'info)
+ 
  (defvar Info-current-file nil
    "Info file that Info is now looking at, or nil.
  This is the name that was specified in Info, not the actual file name.
***************
*** 1619,1631 ****
  (defun Info-scroll-up ()
    "Scroll one screenful forward in Info, considering all nodes as one 
sequence.
  Once you scroll far enough in a node that its menu appears on the screen
! but after point, the next scroll moves into its first subnode.
  
! When you scroll past the end of a node, that goes to the next node; if
! this node has no successor, it moves to the parent node's successor,
! and so on.  If point is inside the menu of a node, it moves to
! subnode indicated by the following menu item.  (That case won't
! normally result from this command, but can happen in other ways.)"
  
    (interactive)
    (if (or (< (window-start) (point-min))
--- 1632,1647 ----
  (defun Info-scroll-up ()
    "Scroll one screenful forward in Info, considering all nodes as one 
sequence.
  Once you scroll far enough in a node that its menu appears on the screen
! but after point, the next scroll moves into its first subnode, unless
! `Info-scroll-prefer-subnodes' is nil.
  
! When you scroll past the end of a node, that goes to the next node if
! `Info-scroll-prefer-subnodes' is non-nil and to the first subnode otherwise;
! if this node has no successor, it moves to the parent node's successor,
! and so on.  If `Info-scroll-prefer-subnodes' is non-nil and point is inside
! the menu of a node, it moves to subnode indicated by the following menu
! item.  (That case won't normally result from this command, but can happen
! in other ways.)"
  
    (interactive)
    (if (or (< (window-start) (point-min))
***************
*** 1634,1645 ****
    (let* ((case-fold-search t)
         (virtual-end (save-excursion
                        (goto-char (point-min))
!                       (if (search-forward "\n* Menu:" nil t)
                            (point)
                          (point-max)))))
      (if (or (< virtual-end (window-start))
            (pos-visible-in-window-p virtual-end))
!       (Info-next-preorder)
        (scroll-up))))
  
  (defun Info-scroll-down ()
--- 1650,1665 ----
    (let* ((case-fold-search t)
         (virtual-end (save-excursion
                        (goto-char (point-min))
!                       (if (and Info-scroll-prefer-subnodes
!                                (search-forward "\n* Menu:" nil t))
                            (point)
                          (point-max)))))
      (if (or (< virtual-end (window-start))
            (pos-visible-in-window-p virtual-end))
!       (cond
!        (Info-scroll-prefer-subnodes (Info-next-preorder))
!        ((Info-no-error (Info-goto-node (Info-extract-menu-counting 1))))
!        (t (Info-next-preorder)))
        (scroll-up))))
  
  (defun Info-scroll-down ()