Commit dac86404 authored by Glenn Morris's avatar Glenn Morris
Browse files

Document make-composed-keymap

* doc/lispref/keymaps.texi (Inheritance and Keymaps):
Mention make-composed-keymap and multiple inheritance.
* etc/NEWS: Related edits.
parent 91d2ed4e
2012-02-06 Glenn Morris <rgm@gnu.org>
* keymaps.texi (Tool Bar): Mention separators.
(Inheritance and Keymaps):
Mention make-composed-keymap and multiple inheritance.
* modes.texi (Running Hooks): Mention run-hook-wrapped.
......
......@@ -432,6 +432,34 @@ for every numeric character code without modifier bits, even if it is
@code{nil}, so these character's bindings are never inherited from
the parent keymap.
@cindex keymap inheritance from multiple maps
Sometimes you want to make a keymap that inherits from more than one
map. You can use the function @code{make-composed-keymap} for this.
@defun make-composed-keymap maps &optional parent
This function returns a new keymap composed of the existing keymap(s)
@var{maps}, and optionally inheriting from a parent keymap
@var{parent}. @var{maps} can be a single keymap or a list of more
than one. When looking up a key in the resulting new map, Emacs
searches in each of the @var{maps}, and then in @var{parent}, stopping
at the first match. A @code{nil} binding in any one of @var{maps}
overrides any binding in @var{parent}, but not a non-@code{nil} binding
in any other of the @var{maps}.
@end defun
@noindent For example, here is how Emacs sets the parent of
@code{help-mode-map}, such that it inherits from both
@code{button-buffer-map} and @code{special-mode-map}:
@example
(defvar help-mode-map
(let ((map (make-sparse-keymap)))
(set-keymap-parent map (make-composed-keymap button-buffer-map
special-mode-map))
... map) ... )
@end example
@node Prefix Keys
@section Prefix Keys
@cindex prefix key
......
......@@ -1412,8 +1412,11 @@ as well as those in the -*- line.
---
** rx.el has a new `group-n' construct for explicitly numbered groups.
** keymaps can inherit from multiple parents.
There is a new function `make-composed-keymap' that [does something].
+++
** New function `make-composed-keymap' that constructs a new keymap
from multiple input maps. You can use this to make a keymap that
inherits from multiple maps, eg:
(set-keymap-parent newmap (make-composed-keymap othermap parent))
+++
** Set `debug-on-event' to make Emacs enter the debugger e.g. on receipt
......
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