(Backspace invokes help): Clarify that keyboard-translate is better

than global-set-key.  Add reference to the manual's section about DEL vs
BS.  Mention normal-erase-is-backspace.

1 files changed, 43 insertions, 6 deletions

diff --git a/man/faq.texi b/man/faq.texi
index 55278bdc887..d9b57f32d82 100644
--- a/man/faq.texi
+++ b/man/faq.texi
@@ -4631,6 +4631,7 @@ actually behaves.
 @section Why does the @key{Backspace} key invoke help?
 @cindex Backspace key invokes help
 @cindex Help invoked by Backspace
+@cindex DEL key does not delete
 
 The @key{Backspace} key (on most keyboards) generates ASCII code 8.
 @kbd{C-h} sends the same code.  In Emacs by default @kbd{C-h} invokes
@@ -4660,22 +4661,45 @@ keyboard or because they don't even have a separate @key{Delete} key.
 In this case, the @key{Backspace} key should be made to behave like
 @key{Delete}.  There are several methods.
 
+@itemize @minus
+@item
+Some terminals (e.g., VT3## terminals) and terminal emulators (e.g.,
+TeraTerm) allow the character generated by the @key{Backspace} key to be
+changed from a setup menu.
+
 @item
-Some terminals (e.g., VT3## terminals) allow the character generated
-by the @key{Backspace} key to be changed from a setup menu.
+You may be able to get a keyboard that is completely programmable, or a
+terminal emulator that supports remapping of any key to any other key.
 
 @item
-You may be able to get a keyboard that is completely programmable.
+With Emacs 21.1 and later, you can control the effect of the
+@key{Backspace} and @key{Delete} keys, on both dumb terminals and a
+windowed displays, by customizing the option
+@code{normal-erase-is-backspace-mode}, or by invoking @kbd{M-x
+normal-erase-is-backspace}.  See the documentation of these symbols
+(@pxref{Emacs Lisp documentation}) for more info.
 
 @item
-Under X or on a dumb terminal, it is possible to swap the
-@key{Backspace} and @key{Delete} keys inside Emacs:
+It is possible to swap the @key{Backspace} and @key{DEL} keys inside
+Emacs:
 
 @lisp
 (keyboard-translate ?\C-h ?\C-?)
 @end lisp
 
-@xref{Swapping keys}, for further details of "keyboard-translate".
+@noindent
+This is the recommended method of forcing @key{Backspace} to act as
+@key{DEL}, because it works even in modes which bind @key{DEL} to
+something other than @code{delete-backward-char}.
+
+Similarly, you could remap @key{DEL} to act as @kbd{C-d}, which by
+default deletes forward:
+
+@lisp
+(keyboard-translate ?\C-? ?\C-d)
+@end lisp
+
+@xref{Swapping keys}, for further details about @code{keyboard-translate}.
 
 @item
 Another approach is to switch key bindings and put help on @kbd{C-x h}
@@ -4688,7 +4712,16 @@ instead:
 (global-set-key "\C-xh" 'help-command) 
 @end lisp
 
+@noindent
+This method is not recommended, though: it only solves the problem for
+those modes which bind @key{DEL} to @code{delete-backward-char}.  Modes
+which bind @key{DEL} to something else, such as @code{view-mode}, will
+not work as you expect when you press the @key{Backspace} key.  For this
+reason, we recommend the the @code{keyboard-translate} method, shown
+above.
+
 Other popular key bindings for help are @kbd{M-?} and @kbd{C-x ?}.
+@end itemize
 
 Don't try to bind @key{DEL} to @code{help-command}, because there are
 many modes that have local bindings of @key{DEL} that will interfere.
@@ -4699,6 +4732,10 @@ When Emacs 21 or later runs on a windowed display, it binds the
 @key{Delete} key to a command which deletes the character at point, to
 make Emacs more consistent with keyboard operation on these systems.
 
+For more information about troubleshooting this problem, see @ref{DEL
+Does Not Delete, , If @key{DEL} Fails to Delete, emacs, The GNU Emacs
+Manual}.
+
 @node stty and Backspace key, Swapping keys, Backspace invokes help, Key bindings
 @section Why doesn't Emacs look at the @file{stty} settings for @key{Backspace} vs. @key{Delete}?
 @cindex @file{stty} and Emacs