Here are the functions and variables pertaining to key lookup.
This function returns the definition of key in keymap. All
the other functions described in this chapter that look up keys use
keymap-lookup. Here are examples:
(keymap-lookup (current-global-map) "C-x C-f")
⇒ find-file
(keymap-lookup (current-global-map) "C-x C-f 1 2 3 4 5")
⇒ 2
If the string or vector key is not a valid key sequence according to the prefix keys specified in keymap, it must be too long and have extra events at the end that do not fit into a single key sequence. Then the value is a number, the number of events at the front of key that compose a complete key.
If accept-defaults is non-nil, then keymap-lookup
considers default bindings as well as bindings for the specific events
in key. Otherwise, keymap-lookup reports only bindings for
the specific sequence key, ignoring default bindings except when
you explicitly ask about them. (To do this, supply t as an
element of key; see Format of Keymaps.)
If key contains a meta character (not a function key), that
character is implicitly replaced by a two-character sequence: the value
of meta-prefix-char, followed by the corresponding non-meta
character. Thus, the first example below is handled by conversion into
the second example.
(keymap-lookup (current-global-map) "M-f")
⇒ forward-word
(keymap-lookup (current-global-map) "ESC f")
⇒ forward-word
The keymap argument can be nil, meaning to look up
key in the current keymaps (as returned by
current-active-maps, see Active Keymaps); or it can be a
keymap or a list of keymaps, meaning to look up key only in the
specified keymaps.
Unlike read-key-sequence, this function does not modify the
specified events in ways that discard information (see Key Sequence Input). In particular, it does not convert letters to lower case and
it does not change drag events to clicks.
Like the normal command loop, keymap-lookup will remap the
command resulting from looking up key by looking up the command
in the current keymaps. However, if the optional third argument
no-remap is non-nil, keymap-lookup returns the
command without remapping.
If the optional argument position is non-nil, it
specifies a mouse position as returned by event-start and
event-end, and the lookup occurs in the keymaps associated with
that position, instead of in keymap. position can also be
a number or a marker, in which case it is interpreted as a buffer
position, and the function uses the keymap properties at that position
instead of at point.
Used in keymaps to undefine keys. It calls ding, but does
not cause an error.
This function returns the binding for key in the current
local keymap, or nil if it is undefined there.
The argument accept-defaults controls checking for default bindings,
as in keymap-lookup (above).
This function returns the binding for command key in the
current global keymap, or nil if it is undefined there.
The argument accept-defaults controls checking for default bindings,
as in keymap-lookup (above).
This function returns a list of all the active minor mode bindings of
key. More precisely, it returns an alist of pairs
(modename . binding), where modename is the
variable that enables the minor mode, and binding is key’s
binding in that mode. If key has no minor-mode bindings, the
value is nil.
If the first binding found is not a prefix definition (a keymap or a symbol defined as a keymap), all subsequent bindings from other minor modes are omitted, since they would be completely shadowed. Similarly, the list omits non-prefix bindings that follow prefix bindings.
The argument accept-defaults controls checking for default
bindings, as in keymap-lookup (above).
This variable is the meta-prefix character code. It is used for translating a meta character to a two-character sequence so it can be looked up in a keymap. For useful results, the value should be a prefix event (see Prefix Keys). The default value is 27, which is the ASCII code for ESC.
As long as the value of meta-prefix-char remains 27, key lookup
translates M-b into ESC b, which is normally defined
as the backward-word command. However, if you were to set
meta-prefix-char to 24, the code for C-x, then Emacs will
translate M-b into C-x b, whose standard binding is the
switch-to-buffer command. (Don’t actually do this!) Here is an
illustration of what would happen:
meta-prefix-char ; The default value.
⇒ 27
(key-binding "\M-b")
⇒ backward-word
?\C-x ; The print representation ⇒ 24 ; of a character.
(setq meta-prefix-char 24)
⇒ 24
(key-binding "\M-b")
⇒ switch-to-buffer ; Now, typing M-b is
; like typing C-x b.
(setq meta-prefix-char 27) ; Avoid confusion!
⇒ 27 ; Restore the default value!
This translation of one event into two happens only for characters, not for other kinds of input events. Thus, M-F1, a function key, is not converted into ESC F1.