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diff --git a/lispref/commands.texi b/lispref/commands.texi deleted file mode 100644 index e2878eee00d..00000000000 --- a/lispref/commands.texi +++ /dev/null @@ -1,2279 +0,0 @@ -@c -*-texinfo-*- -@c This is part of the GNU Emacs Lisp Reference Manual. -@c Copyright (C) 1990, 1991, 1992, 1993, 1994 Free Software Foundation, Inc. -@c See the file elisp.texi for copying conditions. -@setfilename ../info/commands -@node Command Loop, Keymaps, Minibuffers, Top -@chapter Command Loop -@cindex editor command loop -@cindex command loop - - When you run Emacs, it enters the @dfn{editor command loop} almost -immediately. This loop reads key sequences, executes their definitions, -and displays the results. In this chapter, we describe how these things -are done, and the subroutines that allow Lisp programs to do them. - -@menu -* Command Overview:: How the command loop reads commands. -* Defining Commands:: Specifying how a function should read arguments. -* Interactive Call:: Calling a command, so that it will read arguments. -* Command Loop Info:: Variables set by the command loop for you to examine. -* Input Events:: What input looks like when you read it. -* Reading Input:: How to read input events from the keyboard or mouse. -* Waiting:: Waiting for user input or elapsed time. -* Quitting:: How @kbd{C-g} works. How to catch or defer quitting. -* Prefix Command Arguments:: How the commands to set prefix args work. -* Recursive Editing:: Entering a recursive edit, - and why you usually shouldn't. -* Disabling Commands:: How the command loop handles disabled commands. -* Command History:: How the command history is set up, and how accessed. -* Keyboard Macros:: How keyboard macros are implemented. -@end menu - -@node Command Overview -@section Command Loop Overview - - The first thing the command loop must do is read a key sequence, which -is a sequence of events that translates into a command. It does this by -calling the function @code{read-key-sequence}. Your Lisp code can also -call this function (@pxref{Key Sequence Input}). Lisp programs can also -do input at a lower level with @code{read-event} (@pxref{Reading One -Event}) or discard pending input with @code{discard-input} -(@pxref{Event Input Misc}). - - The key sequence is translated into a command through the currently -active keymaps. @xref{Key Lookup}, for information on how this is done. -The result should be a keyboard macro or an interactively callable -function. If the key is @kbd{M-x}, then it reads the name of another -command, which it then calls. This is done by the command -@code{execute-extended-command} (@pxref{Interactive Call}). - - To execute a command requires first reading the arguments for it. -This is done by calling @code{command-execute} (@pxref{Interactive -Call}). For commands written in Lisp, the @code{interactive} -specification says how to read the arguments. This may use the prefix -argument (@pxref{Prefix Command Arguments}) or may read with prompting -in the minibuffer (@pxref{Minibuffers}). For example, the command -@code{find-file} has an @code{interactive} specification which says to -read a file name using the minibuffer. The command's function body does -not use the minibuffer; if you call this command from Lisp code as a -function, you must supply the file name string as an ordinary Lisp -function argument. - - If the command is a string or vector (i.e., a keyboard macro) then -@code{execute-kbd-macro} is used to execute it. You can call this -function yourself (@pxref{Keyboard Macros}). - - To terminate the execution of a running command, type @kbd{C-g}. This -character causes @dfn{quitting} (@pxref{Quitting}). - -@defvar pre-command-hook -The editor command loop runs this normal hook before each command. At -that time, @code{this-command} contains the command that is about to -run, and @code{last-command} describes the previous command. -@end defvar - -@defvar post-command-hook -The editor command loop runs this normal hook after each command -(including commands terminated prematurely by quitting or by errors), -and also when the command loop is first entered. At that time, -@code{this-command} describes the command that just ran, and -@code{last-command} describes the command before that. -@end defvar - -@node Defining Commands -@section Defining Commands -@cindex defining commands -@cindex commands, defining -@cindex functions, making them interactive -@cindex interactive function - - A Lisp function becomes a command when its body contains, at top -level, a form which calls the special form @code{interactive}. This -form does nothing when actually executed, but its presence serves as a -flag to indicate that interactive calling is permitted. Its argument -controls the reading of arguments for an interactive call. - -@menu -* Using Interactive:: General rules for @code{interactive}. -* Interactive Codes:: The standard letter-codes for reading arguments - in various ways. -* Interactive Examples:: Examples of how to read interactive arguments. -@end menu - -@node Using Interactive -@subsection Using @code{interactive} - - This section describes how to write the @code{interactive} form that -makes a Lisp function an interactively-callable command. - -@defspec interactive arg-descriptor -@cindex argument descriptors -This special form declares that the function in which it appears is a -command, and that it may therefore be called interactively (via -@kbd{M-x} or by entering a key sequence bound to it). The argument -@var{arg-descriptor} declares how to compute the arguments to the -command when the command is called interactively. - -A command may be called from Lisp programs like any other function, but -then the caller supplies the arguments and @var{arg-descriptor} has no -effect. - -The @code{interactive} form has its effect because the command loop -(actually, its subroutine @code{call-interactively}) scans through the -function definition looking for it, before calling the function. Once -the function is called, all its body forms including the -@code{interactive} form are executed, but at this time -@code{interactive} simply returns @code{nil} without even evaluating its -argument. -@end defspec - -There are three possibilities for the argument @var{arg-descriptor}: - -@itemize @bullet -@item -It may be omitted or @code{nil}; then the command is called with no -arguments. This leads quickly to an error if the command requires one -or more arguments. - -@item -It may be a Lisp expression that is not a string; then it should be a -form that is evaluated to get a list of arguments to pass to the -command. -@cindex argument evaluation form - -@item -@cindex argument prompt -It may be a string; then its contents should consist of a code character -followed by a prompt (which some code characters use and some ignore). -The prompt ends either with the end of the string or with a newline. -Here is a simple example: - -@smallexample -(interactive "bFrobnicate buffer: ") -@end smallexample - -@noindent -The code letter @samp{b} says to read the name of an existing buffer, -with completion. The buffer name is the sole argument passed to the -command. The rest of the string is a prompt. - -If there is a newline character in the string, it terminates the prompt. -If the string does not end there, then the rest of the string should -contain another code character and prompt, specifying another argument. -You can specify any number of arguments in this way. - -@c Emacs 19 feature -The prompt string can use @samp{%} to include previous argument values -in the prompt. This is done using @code{format} (@pxref{Formatting -Strings}). For example, here is how you could read the name of an -existing buffer followed by a new name to give to that buffer: - -@smallexample -@group -(interactive "bBuffer to rename: \nsRename buffer %s to: ") -@end group -@end smallexample - -@cindex @samp{*} in interactive -@cindex read-only buffers in interactive -If the first character in the string is @samp{*}, then an error is -signaled if the buffer is read-only. - -@cindex @samp{@@} in interactive -@c Emacs 19 feature -If the first character in the string is @samp{@@}, and if the key -sequence used to invoke the command includes any mouse events, then -the window associated with the first of those events is selected -before the command is run. - -You can use @samp{*} and @samp{@@} together; the order does not matter. -Actual reading of arguments is controlled by the rest of the prompt -string (starting with the first character that is not @samp{*} or -@samp{@@}). -@end itemize - -@node Interactive Codes -@comment node-name, next, previous, up -@subsection Code Characters for @code{interactive} -@cindex interactive code description -@cindex description for interactive codes -@cindex codes, interactive, description of -@cindex characters for interactive codes - - The code character descriptions below contain a number of key words, -defined here as follows: - -@table @b -@item Completion -@cindex interactive completion -Provide completion. @key{TAB}, @key{SPC}, and @key{RET} perform name -completion because the argument is read using @code{completing-read} -(@pxref{Completion}). @kbd{?} displays a list of possible completions. - -@item Existing -Require the name of an existing object. An invalid name is not -accepted; the commands to exit the minibuffer do not exit if the current -input is not valid. - -@item Default -@cindex default argument string -A default value of some sort is used if the user enters no text in the -minibuffer. The default depends on the code character. - -@item No I/O -This code letter computes an argument without reading any input. -Therefore, it does not use a prompt string, and any prompt string you -supply is ignored. - -Even though the code letter doesn't use a prompt string, you must follow -it with a newline if it is not the last code character in the string. - -@item Prompt -A prompt immediately follows the code character. The prompt ends either -with the end of the string or with a newline. - -@item Special -This code character is meaningful only at the beginning of the -interactive string, and it does not look for a prompt or a newline. -It is a single, isolated character. -@end table - -@cindex reading interactive arguments - Here are the code character descriptions for use with @code{interactive}: - -@table @samp -@item * -Signal an error if the current buffer is read-only. Special. - -@item @@ -Select the window mentioned in the first mouse event in the key -sequence that invoked this command. Special. - -@item a -A function name (i.e., a symbol which is @code{fboundp}). Existing, -Completion, Prompt. - -@item b -The name of an existing buffer. By default, uses the name of the -current buffer (@pxref{Buffers}). Existing, Completion, Default, -Prompt. - -@item B -A buffer name. The buffer need not exist. By default, uses the name of -a recently used buffer other than the current buffer. Completion, -Prompt. - -@item c -A character. The cursor does not move into the echo area. Prompt. - -@item C -A command name (i.e., a symbol satisfying @code{commandp}). Existing, -Completion, Prompt. - -@item d -@cindex position argument -The position of point, as an integer (@pxref{Point}). No I/O. - -@item D -A directory name. The default is the current default directory of the -current buffer, @code{default-directory} (@pxref{System Environment}). -Existing, Completion, Default, Prompt. - -@item e -The first or next mouse event in the key sequence that invoked the command. -More precisely, @samp{e} gets events which are lists, so you can look at -the data in the lists. @xref{Input Events}. No I/O. - -You can use @samp{e} more than once in a single command's interactive -specification. If the key sequence which invoked the command has -@var{n} events that are lists, the @var{n}th @samp{e} provides the -@var{n}th such event. Events which are not lists, such as function keys -and @sc{ASCII} characters, do not count where @samp{e} is concerned. - -@item f -A file name of an existing file (@pxref{File Names}). The default -directory is @code{default-directory}. Existing, Completion, Default, -Prompt. - -@item F -A file name. The file need not exist. Completion, Default, Prompt. - -@item k -A key sequence (@pxref{Keymap Terminology}). This keeps reading events -until a command (or undefined command) is found in the current key -maps. The key sequence argument is represented as a string or vector. -The cursor does not move into the echo area. Prompt. - -This kind of input is used by commands such as @code{describe-key} and -@code{global-set-key}. - -@item m -@cindex marker argument -The position of the mark, as an integer. No I/O. - -@item n -A number read with the minibuffer. If the input is not a number, the -user is asked to try again. The prefix argument, if any, is not used. -Prompt. - -@item N -@cindex raw prefix argument usage -The raw prefix argument. If the prefix argument is @code{nil}, then -read a number as with @kbd{n}. Requires a number. Prompt. - -@item p -@cindex numeric prefix argument usage -The numeric prefix argument. (Note that this @samp{p} is lower case.) -No I/O.@refill - -@item P -The raw prefix argument. (Note that this @samp{P} is upper case.) -@xref{Prefix Command Arguments}. No I/O.@refill - -@item r -@cindex region argument -Point and the mark, as two numeric arguments, smallest first. This is -the only code letter that specifies two successive arguments rather than -one. No I/O. - -@item s -Arbitrary text, read in the minibuffer and returned as a string -(@pxref{Text from Minibuffer}). Terminate the input with either -@key{LFD} or @key{RET}. (@kbd{C-q} may be used to include either of -these characters in the input.) Prompt. - -@item S -An interned symbol whose name is read in the minibuffer. Any whitespace -character terminates the input. (Use @kbd{C-q} to include whitespace in -the string.) Other characters that normally terminate a symbol (e.g., -parentheses and brackets) do not do so here. Prompt. - -@item v -A variable declared to be a user option (i.e., satisfying the predicate -@code{user-variable-p}). @xref{High-Level Completion}. Existing, -Completion, Prompt. - -@item x -A Lisp object specified in printed representation, terminated with a -@key{LFD} or @key{RET}. The object is not evaluated. @xref{Object from -Minibuffer}. Prompt. - -@item X -@cindex evaluated expression argument -A Lisp form is read as with @kbd{x}, but then evaluated so that its -value becomes the argument for the command. Prompt. -@end table - -@node Interactive Examples -@comment node-name, next, previous, up -@subsection Examples of Using @code{interactive} -@cindex examples of using @code{interactive} -@cindex @code{interactive}, examples of using - - Here are some examples of @code{interactive}: - -@example -@group -(defun foo1 () ; @r{@code{foo1} takes no arguments,} - (interactive) ; @r{just moves forward two words.} - (forward-word 2)) - @result{} foo1 -@end group - -@group -(defun foo2 (n) ; @r{@code{foo2} takes one argument,} - (interactive "p") ; @r{which is the numeric prefix.} - (forward-word (* 2 n))) - @result{} foo2 -@end group - -@group -(defun foo3 (n) ; @r{@code{foo3} takes one argument,} - (interactive "nCount:") ; @r{which is read with the Minibuffer.} - (forward-word (* 2 n))) - @result{} foo3 -@end group - -@group -(defun three-b (b1 b2 b3) - "Select three existing buffers. -Put them into three windows, selecting the last one." -@end group - (interactive "bBuffer1:\nbBuffer2:\nbBuffer3:") - (delete-other-windows) - (split-window (selected-window) 8) - (switch-to-buffer b1) - (other-window 1) - (split-window (selected-window) 8) - (switch-to-buffer b2) - (other-window 1) - (switch-to-buffer b3)) - @result{} three-b -@group -(three-b "*scratch*" "declarations.texi" "*mail*") - @result{} nil -@end group -@end example - -@node Interactive Call -@section Interactive Call -@cindex interactive call - - After the command loop has translated a key sequence into a -definition, it invokes that definition using the function -@code{command-execute}. If the definition is a function that is a -command, @code{command-execute} calls @code{call-interactively}, which -reads the arguments and calls the command. You can also call these -functions yourself. - -@defun commandp object -Returns @code{t} if @var{object} is suitable for calling interactively; -that is, if @var{object} is a command. Otherwise, returns @code{nil}. - -The interactively callable objects include strings and vectors (treated -as keyboard macros), lambda expressions that contain a top-level call to -@code{interactive}, compiled function objects made from such lambda -expressions, autoload objects that are declared as interactive -(non-@code{nil} fourth argument to @code{autoload}), and some of the -primitive functions. - -A symbol is @code{commandp} if its function definition is -@code{commandp}. - -Keys and keymaps are not commands. Rather, they are used to look up -commands (@pxref{Keymaps}). - -See @code{documentation} in @ref{Accessing Documentation}, for a -realistic example of using @code{commandp}. -@end defun - -@defun call-interactively command &optional record-flag -This function calls the interactively callable function @var{command}, -reading arguments according to its interactive calling specifications. -An error is signaled if @var{command} cannot be called interactively -(i.e., it is not a command). Note that keyboard macros (strings and -vectors) are not accepted, even though they are considered commands. - -@cindex record command history -If @var{record-flag} is non-@code{nil}, then this command and its -arguments are unconditionally added to the list @code{command-history}. -Otherwise, the command is added only if it uses the minibuffer to read -an argument. @xref{Command History}. -@end defun - -@defun command-execute command &optional record-flag -@cindex keyboard macro execution -This function executes @var{command} as an editing command. The -argument @var{command} must satisfy the @code{commandp} predicate; i.e., -it must be an interactively callable function or a keyboard macro. - -A string or vector as @var{command} is executed with -@code{execute-kbd-macro}. A function is passed to -@code{call-interactively}, along with the optional @var{record-flag}. - -A symbol is handled by using its function definition in its place. A -symbol with an @code{autoload} definition counts as a command if it was -declared to stand for an interactively callable function. Such a -definition is handled by loading the specified library and then -rechecking the definition of the symbol. -@end defun - -@deffn Command execute-extended-command prefix-argument -@cindex read command name -This function reads a command name from the minibuffer using -@code{completing-read} (@pxref{Completion}). Then it uses -@code{command-execute} to call the specified command. Whatever that -command returns becomes the value of @code{execute-extended-command}. - -@cindex execute with prefix argument -If the command asks for a prefix argument, it receives the value -@var{prefix-argument}. If @code{execute-extended-command} is called -interactively, the current raw prefix argument is used for -@var{prefix-argument}, and thus passed on to whatever command is run. - -@c !!! Should this be @kindex? -@cindex @kbd{M-x} -@code{execute-extended-command} is the normal definition of @kbd{M-x}, -so it uses the string @w{@samp{M-x }} as a prompt. (It would be better -to take the prompt from the events used to invoke -@code{execute-extended-command}, but that is painful to implement.) A -description of the value of the prefix argument, if any, also becomes -part of the prompt. - -@example -@group -(execute-extended-command 1) ----------- Buffer: Minibuffer ---------- -M-x forward-word RET ----------- Buffer: Minibuffer ---------- - @result{} t -@end group -@end example -@end deffn - -@defun interactive-p -This function returns @code{t} if the containing function (the one that -called @code{interactive-p}) was called interactively, with the function -@code{call-interactively}. (It makes no difference whether -@code{call-interactively} was called from Lisp or directly from the -editor command loop.) If the containing function was called by Lisp -evaluation (or with @code{apply} or @code{funcall}), then it was not -called interactively. - -The most common use of @code{interactive-p} is for deciding whether to -print an informative message. As a special exception, -@code{interactive-p} returns @code{nil} whenever a keyboard macro is -being run. This is to suppress the informative messages and speed -execution of the macro. - -For example: - -@example -@group -(defun foo () - (interactive) - (and (interactive-p) - (message "foo"))) - @result{} foo -@end group - -@group -(defun bar () - (interactive) - (setq foobar (list (foo) (interactive-p)))) - @result{} bar -@end group - -@group -;; @r{Type @kbd{M-x foo}.} - @print{} foo -@end group - -@group -;; @r{Type @kbd{M-x bar}.} -;; @r{This does not print anything.} -@end group - -@group -foobar - @result{} (nil t) -@end group -@end example -@end defun - -@node Command Loop Info -@comment node-name, next, previous, up -@section Information from the Command Loop - -The editor command loop sets several Lisp variables to keep status -records for itself and for commands that are run. - -@defvar last-command -This variable records the name of the previous command executed by the -command loop (the one before the current command). Normally the value -is a symbol with a function definition, but this is not guaranteed. - -The value is copied from @code{this-command} when a command returns to -the command loop, except when the command specifies a prefix argument -for the following command. -@end defvar - -@defvar this-command -@cindex current command -This variable records the name of the command now being executed by -the editor command loop. Like @code{last-command}, it is normally a symbol -with a function definition. - -The command loop sets this variable just before running a command, and -copies its value into @code{last-command} when the command finishes -(unless the command specifies a prefix argument for the following -command). - -@cindex kill command repetition -Some commands set this variable during their execution, as a flag for -whatever command runs next. In particular, the functions that kill text -set @code{this-command} to @code{kill-region} so that any kill commands -immediately following will know to append the killed text to the -previous kill. -@end defvar - -If you do not want a particular command to be recognized as the previous -command in the case where it got an error, you must code that command to -prevent this. One way is to set @code{this-command} to @code{t} at the -beginning of the command, and set @code{this-command} back to its proper -value at the end, like this: - -@example -(defun foo (args@dots{}) - (interactive @dots{}) - (let ((old-this-command this-command)) - (setq this-command t) - @r{@dots{}do the work@dots{}} - (setq this-command old-this-command))) -@end example - -@defun this-command-keys -This function returns a string or vector containing the key sequence -that invoked the present command, plus any previous commands that -generated the prefix argument for this command. The value is a string -if all those events were characters. @xref{Input Events}. - -@example -@group -(this-command-keys) -;; @r{Now type @kbd{C-u C-x C-e}.} - @result{} "^U^X^E" -@end group -@end example -@end defun - -@defvar last-nonmenu-event -This variable holds the last input event read as part of a key -sequence, not counting events resulting from mouse menus. - -One use of this variable is to figure out a good default location to -pop up another menu. -@end defvar - -@defvar last-command-event -@defvarx last-command-char -This variable is set to the last input event that was read by the -command loop as part of a command. The principal use of this variable -is in @code{self-insert-command}, which uses it to decide which -character to insert. - -@example -@group -last-command-event -;; @r{Now type @kbd{C-u C-x C-e}.} - @result{} 5 -@end group -@end example - -@noindent -The value is 5 because that is the @sc{ASCII} code for @kbd{C-e}. - -The alias @code{last-command-char} exists for compatibility with -Emacs version 18. -@end defvar - -@c Emacs 19 feature -@defvar last-event-frame -This variable records which frame the last input event was directed to. -Usually this is the frame that was selected when the event was -generated, but if that frame has redirected input focus to another -frame, the value is the frame to which the event was redirected. -@xref{Input Focus}. -@end defvar - -@defvar echo-keystrokes -This variable determines how much time should elapse before command -characters echo. Its value must be an integer, which specifies the -number of seconds to wait before echoing. If the user types a prefix -key (such as @kbd{C-x}) and then delays this many seconds before -continuing, the prefix key is echoed in the echo area. Any subsequent -characters in the same command will be echoed as well. - -If the value is zero, then command input is not echoed. -@end defvar - -@node Input Events -@section Input Events -@cindex events -@cindex input events - -The Emacs command loop reads a sequence of @dfn{input events} that -represent keyboard or mouse activity. The events for keyboard activity -are characters or symbols; mouse events are always lists. This section -describes the representation and meaning of input events in detail. - -@defun eventp object -This function returns non-@code{nil} if @var{event} is an input event. -@end defun - -@menu -* Keyboard Events:: Ordinary characters--keys with symbols on them. -* Function Keys:: Function keys--keys with names, not symbols. -* Mouse Events:: Overview of mouse events. -* Click Events:: Pushing and releasing a mouse button. -* Drag Events:: Moving the mouse before releasing the button. -* Button-Down Events:: A button was pushed and not yet released. -* Repeat Events:: Double and triple click (or drag, or down). -* Motion Events:: Just moving the mouse, not pushing a button. -* Focus Events:: Moving the mouse between frames. -* Event Examples:: Examples of the lists for mouse events. -* Classifying Events:: Finding the modifier keys in an event symbol. - Event types. -* Accessing Events:: Functions to extract info from events. -* Strings of Events:: Special considerations for putting - keyboard character events in a string. -@end menu - -@node Keyboard Events -@subsection Keyboard Events - -There are two kinds of input you can get from the keyboard: ordinary -keys, and function keys. Ordinary keys correspond to characters; the -events they generate are represented in Lisp as characters. In Emacs -versions 18 and earlier, characters were the only events. The event -type of a character event is the character itself (an integer); -see @ref{Classifying Events}. - -@cindex modifier bits (of input character) -@cindex basic code (of input character) -An input character event consists of a @dfn{basic code} between 0 and -255, plus any or all of these @dfn{modifier bits}: - -@table @asis -@item meta -The 2**23 bit in the character code indicates a character -typed with the meta key held down. - -@item control -The 2**22 bit in the character code indicates a non-@sc{ASCII} -control character. - -@sc{ASCII} control characters such as @kbd{C-a} have special basic -codes of their own, so Emacs needs no special bit to indicate them. -Thus, the code for @kbd{C-a} is just 1. - -But if you type a control combination not in @sc{ASCII}, such as -@kbd{%} with the control key, the numeric value you get is the code -for @kbd{%} plus 2**22 (assuming the terminal supports non-@sc{ASCII} -control characters). - -@item shift -The 2**21 bit in the character code indicates an @sc{ASCII} control -character typed with the shift key held down. - -For letters, the basic code indicates upper versus lower case; for -digits and punctuation, the shift key selects an entirely different -character with a different basic code. In order to keep within -the @sc{ASCII} character set whenever possible, Emacs avoids using -the 2**21 bit for those characters. - -However, @sc{ASCII} provides no way to distinguish @kbd{C-A} from -@kbd{C-a}, so Emacs uses the 2**21 bit in @kbd{C-A} and not in -@kbd{C-a}. - -@item hyper -The 2**20 bit in the character code indicates a character -typed with the hyper key held down. - -@item super -The 2**19 bit in the character code indicates a character -typed with the super key held down. - -@item alt -The 2**18 bit in the character code indicates a character typed with -the alt key held down. (On some terminals, the key labeled @key{ALT} -is actually the meta key.) -@end table - - In the future, Emacs may support a larger range of basic codes. We -may also move the modifier bits to larger bit numbers. Therefore, you -should avoid mentioning specific bit numbers in your program. -Instead, the way to test the modifier bits of a character is with the -function @code{event-modifiers} (@pxref{Classifying Events}). - -@node Function Keys -@subsection Function Keys - -@cindex function keys -Most keyboards also have @dfn{function keys}---keys which have names or -symbols that are not characters. Function keys are represented in Lisp -as symbols; the symbol's name is the function key's label, in lower -case. For example, pressing a key labeled @key{F1} places the symbol -@code{f1} in the input stream. - -The event type of a function key event is the event symbol itself. -@xref{Classifying Events}. - -Here are a few special cases in the symbol naming convention for -function keys: - -@table @asis -@item @code{backspace}, @code{tab}, @code{newline}, @code{return}, @code{delete} -These keys correspond to common @sc{ASCII} control characters that have -special keys on most keyboards. - -In @sc{ASCII}, @kbd{C-i} and @key{TAB} are the same character. If the -terminal can distinguish between them, Emacs conveys the distinction to -Lisp programs by representing the former as the integer 9, and the -latter as the symbol @code{tab}. - -Most of the time, it's not useful to distinguish the two. So normally -@code{function-key-map} is set up to map @code{tab} into 9. Thus, a key -binding for character code 9 (the character @kbd{C-i}) also applies to -@code{tab}. Likewise for the other symbols in this group. The function -@code{read-char} likewise converts these events into characters. - -In @sc{ASCII}, @key{BS} is really @kbd{C-h}. But @code{backspace} -converts into the character code 127 (@key{DEL}), not into code 8 -(@key{BS}). This is what most users prefer. - -@item @code{kp-add}, @code{kp-decimal}, @code{kp-divide}, @dots{} -Keypad keys (to the right of the regular keyboard). -@item @code{kp-0}, @code{kp-1}, @dots{} -Keypad keys with digits. -@item @code{kp-f1}, @code{kp-f2}, @code{kp-f3}, @code{kp-f4} -Keypad PF keys. -@item @code{left}, @code{up}, @code{right}, @code{down} -Cursor arrow keys -@end table - -You can use the modifier keys @key{CTRL}, @key{META}, @key{HYPER}, -@key{SUPER}, @key{ALT} and @key{SHIFT} with function keys. The way -to represent them is with prefixes in the symbol name: - -@table @samp -@item A- -The alt modifier. -@item C- -The control modifier. -@item H- -The hyper modifier. -@item M- -The meta modifier. -@item S- -The shift modifier. -@item s- -The super modifier. -@end table - -Thus, the symbol for the key @key{F3} with @key{META} held down is -@kbd{M-@key{f3}}. When you use more than one prefix, we recommend you -write them in alphabetical order; but the order does not matter in -arguments to the key-binding lookup and modification functions. - -@node Mouse Events -@subsection Mouse Events - -Emacs supports four kinds of mouse events: click events, drag events, -button-down events, and motion events. All mouse events are represented -as lists. The @sc{car} of the list is the event type; this says which -mouse button was involved, and which modifier keys were used with it. -The event type can also distinguish double or triple button presses -(@pxref{Repeat Events}). The rest of the list elements give position -and time information. - -For key lookup, only the event type matters: two events of the same type -necessarily run the same command. The command can access the full -values of these events using the @samp{e} interactive code. -@xref{Interactive Codes}. - -A key sequence that starts with a mouse event is read using the keymaps -of the buffer in the window that the mouse was in, not the current -buffer. This does not imply that clicking in a window selects that -window or its buffer---that is entirely under the control of the command -binding of the key sequence. - -@node Click Events -@subsection Click Events -@cindex click event -@cindex mouse click event - -When the user presses a mouse button and releases it at the same -location, that generates a @dfn{click} event. Mouse click events have -this form: - -@example -(@var{event-type} - (@var{window} @var{buffer-pos} (@var{x} . @var{y}) @var{timestamp}) - @var{click-count}) -@end example - -Here is what the elements normally mean: - -@table @asis -@item @var{event-type} -This is a symbol that indicates which mouse button was used. It is -one of the symbols @code{mouse-1}, @code{mouse-2}, @dots{}, where the -buttons are numbered left to right. - -You can also use prefixes @samp{A-}, @samp{C-}, @samp{H-}, @samp{M-}, -@samp{S-} and @samp{s-} for modifiers alt, control, hyper, meta, shift -and super, just as you would with function keys. - -This symbol also serves as the event type of the event. Key bindings -describe events by their types; thus, if there is a key binding for -@code{mouse-1}, that binding would apply to all events whose -@var{event-type} is @code{mouse-1}. - -@item @var{window} -This is the window in which the click occurred. - -@item @var{x}, @var{y} -These are the pixel-based coordinates of the click, relative to the top -left corner of @var{window}, which is @code{(0 . 0)}. - -@item @var{buffer-pos} -This is the buffer position of the character clicked on. - -@item @var{timestamp} -This is the time at which the event occurred, in milliseconds. (Since -this value wraps around the entire range of Emacs Lisp integers in about -five hours, it is useful only for relating the times of nearby events.) - -@item @var{click-count} -This is the number of rapid repeated presses so far of the same mouse -button. @xref{Repeat Events}. -@end table - -The meanings of @var{buffer-pos}, @var{x} and @var{y} are somewhat -different when the event location is in a special part of the screen, -such as the mode line or a scroll bar. - -If the location is in a scroll bar, then @var{buffer-pos} is the symbol -@code{vertical-scroll-bar} or @code{horizontal-scroll-bar}, and the pair -@code{(@var{x} . @var{y})} is replaced with a pair @code{(@var{portion} -. @var{whole})}, where @var{portion} is the distance of the click from -the top or left end of the scroll bar, and @var{whole} is the length of -the entire scroll bar. - -If the position is on a mode line or the vertical line separating -@var{window} from its neighbor to the right, then @var{buffer-pos} is -the symbol @code{mode-line} or @code{vertical-line}. For the mode line, -@var{y} does not have meaningful data. For the vertical line, @var{x} -does not have meaningful data. - -@var{buffer-pos} may be a list containing a symbol (one of the symbols -listed above) instead of just the symbol. This is what happens after -the imaginary prefix keys for these events are inserted into the input -stream. @xref{Key Sequence Input}. - -@node Drag Events -@subsection Drag Events -@cindex drag event -@cindex mouse drag event - -With Emacs, you can have a drag event without even changing your -clothes. A @dfn{drag event} happens every time the user presses a mouse -button and then moves the mouse to a different character position before -releasing the button. Like all mouse events, drag events are -represented in Lisp as lists. The lists record both the starting mouse -position and the final position, like this: - -@example -(@var{event-type} - (@var{window1} @var{buffer-pos1} (@var{x1} . @var{y1}) @var{timestamp1}) - (@var{window2} @var{buffer-pos2} (@var{x2} . @var{y2}) @var{timestamp2}) - @var{click-count}) -@end example - -For a drag event, the name of the symbol @var{event-type} contains the -prefix @samp{drag-}. The second and third elements of the event give -the starting and ending position of the drag. Aside from that, the data -have the same meanings as in a click event (@pxref{Click Events}). You -can access the second element of any mouse event in the same way, with -no need to distinguish drag events from others. - -The @samp{drag-} prefix follows the modifier key prefixes such as -@samp{C-} and @samp{M-}. - -If @code{read-key-sequence} receives a drag event which has no key -binding, and the corresponding click event does have a binding, it -changes the drag event into a click event at the drag's starting -position. This means that you don't have to distinguish between click -and drag events unless you want to. - -@node Button-Down Events -@subsection Button-Down Events -@cindex button-down event - -Click and drag events happen when the user releases a mouse button. -They cannot happen earlier, because there is no way to distinguish a -click from a drag until the button is released. - -If you want to take action as soon as a button is pressed, you need to -handle @dfn{button-down} events.@footnote{Button-down is the -conservative antithesis of drag.} These occur as soon as a button is -pressed. They are represented by lists which look exactly like click -events (@pxref{Click Events}), except that the @var{event-type} symbol -name contains the prefix @samp{down-}. The @samp{down-} prefix follows -modifier key prefixes such as @samp{C-} and @samp{M-}. - -The function @code{read-key-sequence}, and the Emacs command loop, -ignore any button-down events that don't have command bindings. This -means that you need not worry about defining button-down events unless -you want them to do something. The usual reason to define a button-down -event is so that you can track mouse motion (by reading motion events) -until the button is released. @xref{Motion Events}. - -@node Repeat Events -@subsection Repeat Events -@cindex repeat events -@cindex double-click events -@cindex triple-click events - -If you press the same mouse button more than once in quick succession -without moving the mouse, Emacs generates special @dfn{repeat} mouse -events for the second and subsequent presses. - -The most common repeat events are @dfn{double-click} events. Emacs -generates a double-click event when you click a button twice; the event -happens when you release the button (as is normal for all click -events). - -The event type of a double-click event contains the prefix -@samp{double-}. Thus, a double click on the second mouse button with -@key{meta} held down comes to the Lisp program as -@code{M-double-mouse-2}. If a double-click event has no binding, the -binding of the corresponding ordinary click event is used to execute -it. Thus, you need not pay attention to the double click feature -unless you really want to. - -When the user performs a double click, Emacs generates first an ordinary -click event, and then a double-click event. Therefore, you must design -the command binding of the double click event to assume that the -single-click command has already run. It must produce the desired -results of a double click, starting from the results of a single click. - -This is convenient, if the meaning of a double click somehow ``builds -on'' the meaning of a single click---which is recommended user interface -design practice for double clicks. - -If you click a button, then press it down again and start moving the -mouse with the button held down, then you get a @dfn{double-drag} event -when you ultimately release the button. Its event type contains -@samp{double-drag} instead of just @samp{drag}. If a double-drag event -has no binding, Emacs looks for an alternate binding as if the event -were an ordinary click. - -Before the double-click or double-drag event, Emacs generates a -@dfn{double-down} event when the user presses the button down for the -second time. Its event type contains @samp{double-down} instead of just -@samp{down}. If a double-down event has no binding, Emacs looks for an -alternate binding as if the event were an ordinary button-down event. -If it finds no binding that way either, the double-down event is -ignored. - -To summarize, when you click a button and then press it again right -away, Emacs generates a double-down event, followed by either a -double-click or a double-drag. - -If you click a button twice and then press it again, all in quick -succession, Emacs generates a @dfn{triple-down} event, followed by -either a @dfn{triple-click} or a @dfn{triple-drag}. The event types of -these events contain @samp{triple} instead of @samp{double}. If any -triple event has no binding, Emacs uses the binding that it would use -for the corresponding double event. - -If you click a button three or more times and then press it again, the -events for the presses beyond the third are all triple events. Emacs -does not have separate event types for quadruple, quintuple, etc.@: -events. However, you can look at the event list to find out precisely -how many times the button was pressed. - -@defun event-click-count event -This function returns the number of consecutive button presses that led -up to @var{event}. If @var{event} is a double-down, double-click or -double-drag event, the value is 2. If @var{event} is a triple event, -the value is 3 or greater. If @var{event} is an ordinary mouse event -(not a repeat event), the value is 1. -@end defun - -@defvar double-click-time -To generate repeat events, successive mouse button presses must be at -the same screen position, and the number of milliseconds between -successive button presses must be less than the value of -@code{double-click-time}. Setting @code{double-click-time} to -@code{nil} disables multi-click detection entirely. Setting it to -@code{t} removes the time limit; Emacs then detects multi-clicks by -position only. -@end defvar - -@node Motion Events -@subsection Motion Events -@cindex motion event -@cindex mouse motion events - -Emacs sometimes generates @dfn{mouse motion} events to describe motion -of the mouse without any button activity. Mouse motion events are -represented by lists that look like this: - -@example -(mouse-movement - (@var{window} @var{buffer-pos} (@var{x} . @var{y}) @var{timestamp})) -@end example - -The second element of the list describes the current position of the -mouse, just as in a click event (@pxref{Click Events}). - -The special form @code{track-mouse} enables generation of motion events -within its body. Outside of @code{track-mouse} forms, Emacs does not -generate events for mere motion of the mouse, and these events do not -appear. - -@defspec track-mouse body@dots{} -This special form executes @var{body}, with generation of mouse motion -events enabled. Typically @var{body} would use @code{read-event} -to read the motion events and modify the display accordingly. - -When the user releases the button, that generates a click event. -Typically, @var{body} should return when it sees the click event, and -discard that event. -@end defspec - -@node Focus Events -@subsection Focus Events -@cindex focus event - -Window systems provide general ways for the user to control which window -gets keyboard input. This choice of window is called the @dfn{focus}. -When the user does something to switch between Emacs frames, that -generates a @dfn{focus event}. The normal definition of a focus event, -in the global keymap, is to select a new frame within Emacs, as the user -would expect. @xref{Input Focus}. - -Focus events are represented in Lisp as lists that look like this: - -@example -(switch-frame @var{new-frame}) -@end example - -@noindent -where @var{new-frame} is the frame switched to. - -Most X window window managers are set up so that just moving the mouse -into a window is enough to set the focus there. Emacs appears to do -this, because it changes the cursor to solid in the new frame. However, -there is no need for the Lisp program to know about the focus change -until some other kind of input arrives. So Emacs generates a focus -event only when the user actually types a keyboard key or presses a -mouse button in the new frame; just moving the mouse between frames does -not generate a focus event. - -A focus event in the middle of a key sequence would garble the -sequence. So Emacs never generates a focus event in the middle of a key -sequence. If the user changes focus in the middle of a key -sequence---that is, after a prefix key---then Emacs reorders the events -so that the focus event comes either before or after the multi-event key -sequence, and not within it. - -@node Event Examples -@subsection Event Examples - -If the user presses and releases the left mouse button over the same -location, that generates a sequence of events like this: - -@smallexample -(down-mouse-1 (#<window 18 on NEWS> 2613 (0 . 38) -864320)) -(mouse-1 (#<window 18 on NEWS> 2613 (0 . 38) -864180)) -@end smallexample - -While holding the control key down, the user might hold down the -second mouse button, and drag the mouse from one line to the next. -That produces two events, as shown here: - -@smallexample -(C-down-mouse-2 (#<window 18 on NEWS> 3440 (0 . 27) -731219)) -(C-drag-mouse-2 (#<window 18 on NEWS> 3440 (0 . 27) -731219) - (#<window 18 on NEWS> 3510 (0 . 28) -729648)) -@end smallexample - -While holding down the meta and shift keys, the user might press the -second mouse button on the window's mode line, and then drag the mouse -into another window. That produces a pair of events like these: - -@smallexample -(M-S-down-mouse-2 (#<window 18 on NEWS> mode-line (33 . 31) -457844)) -(M-S-drag-mouse-2 (#<window 18 on NEWS> mode-line (33 . 31) -457844) - (#<window 20 on carlton-sanskrit.tex> 161 (33 . 3) - -453816)) -@end smallexample - -@node Classifying Events -@subsection Classifying Events -@cindex event type - - Every event has an @dfn{event type} which classifies the event for key -binding purposes. For a keyboard event, the event type equals the event -value; thus, the event type for a character is the character, and the -event type for a function key symbol is the symbol itself. For events -which are lists, the event type is the symbol in the @sc{car} of the -list. Thus, the event type is always a symbol or a character. - - Two events of the same type are equivalent where key bindings are -concerned; thus, they always run the same command. That does not -necessarily mean they do the same things, however, as some commands look -at the whole event to decide what to do. For example, some commands use -the location of a mouse event to decide where in the buffer to act. - - Sometimes broader classifications of events are useful. For example, -you might want to ask whether an event involved the @key{META} key, -regardless of which other key or mouse button was used. - - The functions @code{event-modifiers} and @code{event-basic-type} are -provided to get such information conveniently. - -@defun event-modifiers event -This function returns a list of the modifiers that @var{event} has. The -modifiers are symbols; they include @code{shift}, @code{control}, -@code{meta}, @code{alt}, @code{hyper} and @code{super}. In addition, -the modifiers list of a mouse event symbol always contains one of -@code{click}, @code{drag}, and @code{down}. - -The argument @var{event} may be an entire event object, or just an event -type. - -Here are some examples: - -@example -(event-modifiers ?a) - @result{} nil -(event-modifiers ?\C-a) - @result{} (control) -(event-modifiers ?\C-%) - @result{} (control) -(event-modifiers ?\C-\S-a) - @result{} (control shift) -(event-modifiers 'f5) - @result{} nil -(event-modifiers 's-f5) - @result{} (super) -(event-modifiers 'M-S-f5) - @result{} (meta shift) -(event-modifiers 'mouse-1) - @result{} (click) -(event-modifiers 'down-mouse-1) - @result{} (down) -@end example - -The modifiers list for a click event explicitly contains @code{click}, -but the event symbol name itself does not contain @samp{click}. -@end defun - -@defun event-basic-type event -This function returns the key or mouse button that @var{event} -describes, with all modifiers removed. For example: - -@example -(event-basic-type ?a) - @result{} 97 -(event-basic-type ?A) - @result{} 97 -(event-basic-type ?\C-a) - @result{} 97 -(event-basic-type ?\C-\S-a) - @result{} 97 -(event-basic-type 'f5) - @result{} f5 -(event-basic-type 's-f5) - @result{} f5 -(event-basic-type 'M-S-f5) - @result{} f5 -(event-basic-type 'down-mouse-1) - @result{} mouse-1 -@end example -@end defun - -@defun mouse-movement-p object -This function returns non-@code{nil} if @var{object} is a mouse movement -event. -@end defun - -@node Accessing Events -@subsection Accessing Events - - This section describes convenient functions for accessing the data in -a mouse button or motion event. - - These two functions return the starting or ending position of a -mouse-button event. The position is a list of this form: - -@example -(@var{window} @var{buffer-position} (@var{col} . @var{row}) @var{timestamp}) -@end example - -@defun event-start event -This returns the starting position of @var{event}. - -If @var{event} is a click or button-down event, this returns the -location of the event. If @var{event} is a drag event, this returns the -drag's starting position. -@end defun - -@defun event-end event -This returns the ending position of @var{event}. - -If @var{event} is a drag event, this returns the position where the user -released the mouse button. If @var{event} is a click or button-down -event, the value is actually the starting position, which is the only -position such events have. -@end defun - - These four functions take a position-list as described above, and -return various parts of it. - -@defun posn-window position -Return the window that @var{position} is in. -@end defun - -@defun posn-point position -Return the buffer position in @var{position}. This is an integer. -@end defun - -@defun posn-x-y position -Return the pixel-based x and y coordinates column in @var{position}, as -a cons cell @code{(@var{x} . @var{y})}. -@end defun - -@defun posn-col-row position -Return the row and column (in units of characters) of @var{position}, as -a cons cell @code{(@var{col} . @var{row})}. These are computed from the -@var{x} and @var{y} values actually found in @var{position}. -@end defun - -@defun posn-timestamp position -Return the timestamp in @var{position}. -@end defun - -@defun scroll-bar-scale ratio total -This function multiples (in effect) @var{ratio} by @var{total}, rounding -the result to an integer. The argument @var{ratio} is not a number, but -rather a pair @code{(@var{num} . @var{denom})}. - -This function is handy for scaling a position on a scroll bar into a -buffer position. Here's how to do that: - -@example -(+ (point-min) - (scroll-bar-scale - (posn-col-row (event-start event)) - (- (point-max) (point-min)))) -@end example -@end defun - -@node Strings of Events -@subsection Putting Keyboard Events in Strings - - In most of the places where strings are used, we conceptualize the -string as containing text characters---the same kind of characters found -in buffers or files. Occasionally Lisp programs use strings which -conceptually contain keyboard characters; for example, they may be key -sequences or keyboard macro definitions. There are special rules for -how to put keyboard characters into a string, because they are not -limited to the range of 0 to 255 as text characters are. - - A keyboard character typed using the @key{META} key is called a -@dfn{meta character}. The numeric code for such an event includes the -2**23 bit; it does not even come close to fitting in a string. However, -earlier Emacs versions used a different representation for these -characters, which gave them codes in the range of 128 to 255. That did -fit in a string, and many Lisp programs contain string constants that -use @samp{\M-} to express meta characters, especially as the argument to -@code{define-key} and similar functions. - - We provide backward compatibility to run those programs using special -rules for how to put a keyboard character event in a string. Here are -the rules: - -@itemize @bullet -@item -If the keyboard character value is in the range of 0 to 127, it can go -in the string unchanged. - -@item -The meta variants of those characters, with codes in the range of 2**23 -to 2**23+127, can also go in the string, but you must change their -numeric values. You must set the 2**7 bit instead of the 2**23 bit, -resulting in a value between 128 and 255. - -@item -Other keyboard character events cannot fit in a string. This includes -keyboard events in the range of 128 to 255. -@end itemize - - Functions such as @code{read-key-sequence} that can construct strings -of keyboard input characters follow these rules. They construct vectors -instead of strings, when the events won't fit in a string. - - When you use the read syntax @samp{\M-} in a string, it produces a -code in the range of 128 to 255---the same code that you get if you -modify the corresponding keyboard event to put it in the string. Thus, -meta events in strings work consistently regardless of how they get into -the strings. - - The reason we changed the representation of meta characters as -keyboard events is to make room for basic character codes beyond 127, -and support meta variants of such larger character codes. - - New programs can avoid dealing with these special compatibility rules -by using vectors instead of strings for key sequences when there is any -possibility that they might contain meta characters, and by using -@code{listify-key-sequence} to access a string of events. - -@defun listify-key-sequence key -This function converts the string or vector @var{key} to a list of -events which you can put in @code{unread-command-events}. Converting a -vector is simple, but converting a string is tricky because of the -special representation used for meta characters in a string. -@end defun - -@node Reading Input -@section Reading Input - - The editor command loop reads keyboard input using the function -@code{read-key-sequence}, which uses @code{read-event}. These and other -functions for keyboard input are also available for use in Lisp -programs. See also @code{momentary-string-display} in @ref{Temporary -Displays}, and @code{sit-for} in @ref{Waiting}. @xref{Terminal Input}, -for functions and variables for controlling terminal input modes and -debugging terminal input. - - For higher-level input facilities, see @ref{Minibuffers}. - -@menu -* Key Sequence Input:: How to read one key sequence. -* Reading One Event:: How to read just one event. -* Quoted Character Input:: Asking the user to specify a character. -* Event Input Misc:: How to reread or throw away input events. -@end menu - -@node Key Sequence Input -@subsection Key Sequence Input -@cindex key sequence input - - The command loop reads input a key sequence at a time, by calling -@code{read-key-sequence}. Lisp programs can also call this function; -for example, @code{describe-key} uses it to read the key to describe. - -@defun read-key-sequence prompt -@cindex key sequence -This function reads a key sequence and returns it as a string or -vector. It keeps reading events until it has accumulated a full key -sequence; that is, enough to specify a non-prefix command using the -currently active keymaps. - -If the events are all characters and all can fit in a string, then -@code{read-key-sequence} returns a string (@pxref{Strings of Events}). -Otherwise, it returns a vector, since a vector can hold all kinds of -events---characters, symbols, and lists. The elements of the string or -vector are the events in the key sequence. - -The function @code{read-key-sequence} suppresses quitting: @kbd{C-g} -typed while reading with this function works like any other character, -and does not set @code{quit-flag}. @xref{Quitting}. - -The argument @var{prompt} is either a string to be displayed in the echo -area as a prompt, or @code{nil}, meaning not to display a prompt. - -In the example below, the prompt @samp{?} is displayed in the echo area, -and the user types @kbd{C-x C-f}. - -@example -(read-key-sequence "?") - -@group ----------- Echo Area ---------- -?@kbd{C-x C-f} ----------- Echo Area ---------- - - @result{} "^X^F" -@end group -@end example -@end defun - -@defvar num-input-keys -@c Emacs 19 feature -This variable's value is the number of key sequences processed so far in -this Emacs session. This includes key sequences read from the terminal -and key sequences read from keyboard macros being executed. -@end defvar - -@cindex upper case key sequence -@cindex downcasing in @code{lookup-key} -If an input character is an upper case letter and has no key binding, -but its lower case equivalent has one, then @code{read-key-sequence} -converts the character to lower case. Note that @code{lookup-key} does -not perform case conversion in this way. - -The function @code{read-key-sequence} also transforms some mouse events. -It converts unbound drag events into click events, and discards unbound -button-down events entirely. It also reshuffles focus events so that they -never appear in a key sequence with any other events. - -When mouse events occur in special parts of a window, such as a mode -line or a scroll bar, the event type shows nothing special---it is the -same symbol that would normally represent that combination of mouse -button and modifier keys. The information about the window part is -kept elsewhere in the event---in the coordinates. But -@code{read-key-sequence} translates this information into imaginary -prefix keys, all of which are symbols: @code{mode-line}, -@code{vertical-line}, @code{horizontal-scroll-bar} and -@code{vertical-scroll-bar}. - -You can define meanings for mouse clicks in special window parts by -defining key sequences using these imaginary prefix keys. - -For example, if you call @code{read-key-sequence} and then click the -mouse on the window's mode line, you get an event like this: - -@example -(read-key-sequence "Click on the mode line: ") - @result{} [mode-line - (mouse-1 - (#<window 6 on NEWS> mode-line - (40 . 63) 5959987))] -@end example - -@node Reading One Event -@subsection Reading One Event - - The lowest level functions for command input are those which read a -single event. - -@defun read-event -This function reads and returns the next event of command input, waiting -if necessary until an event is available. Events can come directly from -the user or from a keyboard macro. - -The function @code{read-event} does not display any message to indicate -it is waiting for input; use @code{message} first, if you wish to -display one. If you have not displayed a message, @code{read-event} -prompts by echoing: it displays descriptions of the events that led to -or were read by the current command. @xref{The Echo Area}. - -If @code{cursor-in-echo-area} is non-@code{nil}, then @code{read-event} -moves the cursor temporarily to the echo area, to the end of any message -displayed there. Otherwise @code{read-event} does not move the cursor. - -Here is what happens if you call @code{read-event} and then press the -right-arrow function key: - -@example -@group -(read-event) - @result{} right -@end group -@end example -@end defun - -@defun read-char -This function reads and returns a character of command input. It -discards any events that are not characters, until it gets a character. - -In the first example, the user types the character @kbd{1} (@sc{ASCII} -code 49). The second example shows a keyboard macro definition that -calls @code{read-char} from the minibuffer using @code{eval-expression}. -@code{read-char} reads the keyboard macro's very next character, which -is @kbd{1}. Then @code{eval-expression} displays its return value in -the echo area. - -@example -@group -(read-char) - @result{} 49 -@end group - -@group -(symbol-function 'foo) - @result{} "^[^[(read-char)^M1" -@end group -@group -(execute-kbd-macro 'foo) - @print{} 49 - @result{} nil -@end group -@end example -@end defun - -@node Quoted Character Input -@subsection Quoted Character Input -@cindex quoted character input - - You can use the function @code{read-quoted-char} when to ask the user -to specify a character, and allow the user to specify a control or meta -character conveniently with quoting or as an octal character code. The -command @code{quoted-insert} uses this function. - -@defun read-quoted-char &optional prompt -@cindex octal character input -@cindex control characters, reading -@cindex nonprinting characters, reading -This function is like @code{read-char}, except that if the first -character read is an octal digit (0-7), it reads up to two more octal digits -(but stopping if a non-octal digit is found) and returns the -character represented by those digits in octal. - -Quitting is suppressed when the first character is read, so that the -user can enter a @kbd{C-g}. @xref{Quitting}. - -If @var{prompt} is supplied, it specifies a string for prompting the -user. The prompt string is always displayed in the echo area, followed -by a single @samp{-}. - -In the following example, the user types in the octal number 177 (which -is 127 in decimal). - -@example -(read-quoted-char "What character") - -@group ----------- Echo Area ---------- -What character-@kbd{177} ----------- Echo Area ---------- - - @result{} 127 -@end group -@end example -@end defun - -@need 3000 - -@node Event Input Misc -@subsection Miscellaneous Event Input Features - -This section describes how to ``peek ahead'' at events without using -them up, how to check for pending input, and how to discard pending -input. - -@defvar unread-command-events -@cindex next input -@cindex peeking at input -This variable holds a list of events waiting to be read as command -input. The events are used in the order they appear in the list, and -removed one by one as they are used. - -The variable is needed because in some cases a function reads a event -and then decides not to use it. Storing the event in this variable -causes it to be processed normally, by the command loop or by the -functions to read command input. - -@cindex prefix argument unreading -For example, the function that implements numeric prefix arguments reads -any number of digits. When it finds a non-digit event, it must unread -the event so that it can be read normally by the command loop. -Likewise, incremental search uses this feature to unread events with no -special meaning in a search, because these events should exit the search -and then execute normally. - -The reliable and easy way to extract events from a key sequence to put -them in @code{unread-command-events} is to use -@code{listify-key-sequence} (@pxref{Strings of Events}). -@end defvar - -@defvar unread-command-char -This variable holds a character to be read as command input. -A value of -1 means ``empty''. - -This variable is mostly obsolete now that you can use -@code{unread-command-events} instead; it exists only to support programs -written for Emacs versions 18 and earlier. -@end defvar - -@defun input-pending-p -@cindex waiting for command key input -This function determines whether any command input is currently -available to be read. It returns immediately, with value @code{t} if -there is available input, @code{nil} otherwise. On rare occasions it -may return @code{t} when no input is available. -@end defun - -@defvar last-input-event -This variable records the last terminal input event read, whether -as part of a command or explicitly by a Lisp program. - -In the example below, the Lisp program reads the character @kbd{1}, -@sc{ASCII} code 49. It becomes the value of @code{last-input-event}, -while @kbd{C-e} (from the @kbd{C-x C-e} command used to evaluate this -expression) remains the value of @code{last-command-event}. - -@example -@group -(progn (print (read-char)) - (print last-command-event) - last-input-event) - @print{} 49 - @print{} 5 - @result{} 49 -@end group -@end example - -@vindex last-input-char -The alias @code{last-input-char} exists for compatibility with -Emacs version 18. -@end defvar - -@defun discard-input -@cindex flush input -@cindex discard input -@cindex terminate keyboard macro -This function discards the contents of the terminal input buffer and -cancels any keyboard macro that might be in the process of definition. -It returns @code{nil}. - -In the following example, the user may type a number of characters right -after starting the evaluation of the form. After the @code{sleep-for} -finishes sleeping, @code{discard-input} discards any characters typed -during the sleep. - -@example -(progn (sleep-for 2) - (discard-input)) - @result{} nil -@end example -@end defun - -@node Waiting -@section Waiting for Elapsed Time or Input -@cindex pausing -@cindex waiting - - The wait functions are designed to wait for a certain amount of time -to pass or until there is input. For example, you may wish to pause in -the middle of a computation to allow the user time to view the display. -@code{sit-for} pauses and updates the screen, and returns immediately if -input comes in, while @code{sleep-for} pauses without updating the -screen. - -@defun sit-for seconds &optional millisec nodisp -This function performs redisplay (provided there is no pending input -from the user), then waits @var{seconds} seconds, or until input is -available. The value is @code{t} if @code{sit-for} waited the full -time with no input arriving (see @code{input-pending-p} in @ref{Event -Input Misc}). Otherwise, the value is @code{nil}. - -@c Emacs 19 feature ??? maybe not working yet -The optional argument @var{millisec} specifies an additional waiting -period measured in milliseconds. This adds to the period specified by -@var{seconds}. Not all operating systems support waiting periods other -than multiples of a second; on those that do not, you get an error if -you specify nonzero @var{millisec}. - -@cindex forcing redisplay -Redisplay is always preempted if input arrives, and does not happen at -all if input is available before it starts. Thus, there is no way to -force screen updating if there is pending input; however, if there is no -input pending, you can force an update with no delay by using -@code{(sit-for 0)}. - -If @var{nodisp} is non-@code{nil}, then @code{sit-for} does not -redisplay, but it still returns as soon as input is available (or when -the timeout elapses). - -The usual purpose of @code{sit-for} is to give the user time to read -text that you display. -@end defun - -@defun sleep-for seconds &optional millisec -This function simply pauses for @var{seconds} seconds without updating -the display. It pays no attention to available input. It returns -@code{nil}. - -@c Emacs 19 feature ??? maybe not working yet -The optional argument @var{millisec} specifies an additional waiting -period measured in milliseconds. This adds to the period specified by -@var{seconds}. Not all operating systems support waiting periods other -than multiples of a second; on those that do not, you get an error if -you specify nonzero @var{millisec}. - -Use @code{sleep-for} when you wish to guarantee a delay. -@end defun - - @xref{Time of Day}, for functions to get the current time. - -@node Quitting -@section Quitting -@cindex @kbd{C-g} -@cindex quitting - - Typing @kbd{C-g} while the command loop has run a Lisp function causes -Emacs to @dfn{quit} whatever it is doing. This means that control -returns to the innermost active command loop. - - Typing @kbd{C-g} while the command loop is waiting for keyboard input -does not cause a quit; it acts as an ordinary input character. In the -simplest case, you cannot tell the difference, because @kbd{C-g} -normally runs the command @code{keyboard-quit}, whose effect is to quit. -However, when @kbd{C-g} follows a prefix key, the result is an undefined -key. The effect is to cancel the prefix key as well as any prefix -argument. - - In the minibuffer, @kbd{C-g} has a different definition: it aborts out -of the minibuffer. This means, in effect, that it exits the minibuffer -and then quits. (Simply quitting would return to the command loop -@emph{within} the minibuffer.) The reason why @kbd{C-g} does not quit -directly when the command reader is reading input is so that its meaning -can be redefined in the minibuffer in this way. @kbd{C-g} following a -prefix key is not redefined in the minibuffer, and it has its normal -effect of canceling the prefix key and prefix argument. This too -would not be possible if @kbd{C-g} always quit directly. - - When @kbd{C-g} does directly quit, it does so by the variable -@code{quit-flag} to @code{t}. Emacs checks this variable at appropriate -times and quits if it is not @code{nil}. Setting @code{quit-flag} -non-@code{nil} in any way thus causes a quit. - - At the level of C code, quitting cannot happen just anywhere; only at the -special places which check @code{quit-flag}. The reason for this is -that quitting at other places might leave an inconsistency in Emacs's -internal state. Because quitting is delayed until a safe place, quitting -cannot make Emacs crash. - - Certain functions such as @code{read-key-sequence} or -@code{read-quoted-char} prevent quitting entirely even though they wait -for input. Instead of quitting, @kbd{C-g} serves as the requested -input. In the case of @code{read-key-sequence}, this serves to bring -about the special behavior of @kbd{C-g} in the command loop. In the -case of @code{read-quoted-char}, this is so that @kbd{C-q} can be used -to quote a @kbd{C-g}. - - You can prevent quitting for a portion of a Lisp function by binding -the variable @code{inhibit-quit} to a non-@code{nil} value. Then, -although @kbd{C-g} still sets @code{quit-flag} to @code{t} as usual, the -usual result of this---a quit---is prevented. Eventually, -@code{inhibit-quit} will become @code{nil} again, such as when its -binding is unwound at the end of a @code{let} form. At that time, if -@code{quit-flag} is still non-@code{nil}, the requested quit happens -immediately. This behavior is ideal for a ``critical section'', where -you wish to make sure that quitting does not happen within that part of -the program. - -@cindex @code{read-quoted-char} quitting - In some functions (such as @code{read-quoted-char}), @kbd{C-g} is -handled in a special way which does not involve quitting. This is done -by reading the input with @code{inhibit-quit} bound to @code{t}, and -setting @code{quit-flag} to @code{nil} before @code{inhibit-quit} -becomes @code{nil} again. This excerpt from the definition of -@code{read-quoted-char} shows how this is done; it also shows that -normal quitting is permitted after the first character of input. - -@example -(defun read-quoted-char (&optional prompt) - "@dots{}@var{documentation}@dots{}" - (let ((count 0) (code 0) char) - (while (< count 3) - (let ((inhibit-quit (zerop count)) - (help-form nil)) - (and prompt (message "%s-" prompt)) - (setq char (read-char)) - (if inhibit-quit (setq quit-flag nil))) - @dots{}) - (logand 255 code))) -@end example - -@defvar quit-flag -If this variable is non-@code{nil}, then Emacs quits immediately, unless -@code{inhibit-quit} is non-@code{nil}. Typing @kbd{C-g} ordinarily sets -@code{quit-flag} non-@code{nil}, regardless of @code{inhibit-quit}. -@end defvar - -@defvar inhibit-quit -This variable determines whether Emacs should quit when @code{quit-flag} -is set to a value other than @code{nil}. If @code{inhibit-quit} is -non-@code{nil}, then @code{quit-flag} has no special effect. -@end defvar - -@deffn Command keyboard-quit -This function signals the @code{quit} condition with @code{(signal 'quit -nil)}. This is the same thing that quitting does. (See @code{signal} -in @ref{Errors}.) -@end deffn - - You can specify a character other than @kbd{C-g} to use for quitting. -See the function @code{set-input-mode} in @ref{Terminal Input}. - -@node Prefix Command Arguments -@section Prefix Command Arguments -@cindex prefix argument -@cindex raw prefix argument -@cindex numeric prefix argument - - Most Emacs commands can use a @dfn{prefix argument}, a number -specified before the command itself. (Don't confuse prefix arguments -with prefix keys.) The prefix argument is represented by a value that -is always available (though it may be @code{nil}, meaning there is no -prefix argument). Each command may use the prefix argument or ignore -it. - - There are two representations of the prefix argument: @dfn{raw} and -@dfn{numeric}. The editor command loop uses the raw representation -internally, and so do the Lisp variables that store the information, but -commands can request either representation. - - Here are the possible values of a raw prefix argument: - -@itemize @bullet -@item -@code{nil}, meaning there is no prefix argument. Its numeric value is -1, but numerous commands make a distinction between @code{nil} and the -integer 1. - -@item -An integer, which stands for itself. - -@item -A list of one element, which is an integer. This form of prefix -argument results from one or a succession of @kbd{C-u}'s with no -digits. The numeric value is the integer in the list, but some -commands make a distinction between such a list and an integer alone. - -@item -The symbol @code{-}. This indicates that @kbd{M--} or @kbd{C-u -} was -typed, without following digits. The equivalent numeric value is -@minus{}1, but some commands make a distinction between the integer -@minus{}1 and the symbol @code{-}. -@end itemize - -We illustrate these possibilities by calling the following function with -various prefixes: - -@example -@group -(defun display-prefix (arg) - "Display the value of the raw prefix arg." - (interactive "P") - (message "%s" arg)) -@end group -@end example - -@noindent -Here are the results of calling @code{display-prefix} with various -raw prefix arguments: - -@example - M-x display-prefix @print{} nil - -C-u M-x display-prefix @print{} (4) - -C-u C-u M-x display-prefix @print{} (16) - -C-u 3 M-x display-prefix @print{} 3 - -M-3 M-x display-prefix @print{} 3 ; @r{(Same as @code{C-u 3}.)} - -C-u - M-x display-prefix @print{} - - -M-- M-x display-prefix @print{} - ; @r{(Same as @code{C-u -}.)} - -C-u - 7 M-x display-prefix @print{} -7 - -M-- 7 M-x display-prefix @print{} -7 ; @r{(Same as @code{C-u -7}.)} -@end example - - Emacs uses two variables to store the prefix argument: -@code{prefix-arg} and @code{current-prefix-arg}. Commands such as -@code{universal-argument} that set up prefix arguments for other -commands store them in @code{prefix-arg}. In contrast, -@code{current-prefix-arg} conveys the prefix argument to the current -command, so setting it has no effect on the prefix arguments for future -commands. - - Normally, commands specify which representation to use for the prefix -argument, either numeric or raw, in the @code{interactive} declaration. -(@xref{Interactive Call}.) Alternatively, functions may look at the -value of the prefix argument directly in the variable -@code{current-prefix-arg}, but this is less clean. - -@defun prefix-numeric-value arg -This function returns the numeric meaning of a valid raw prefix argument -value, @var{arg}. The argument may be a symbol, a number, or a list. -If it is @code{nil}, the value 1 is returned; if it is any other symbol, -the value @minus{}1 is returned. If it is a number, that number is -returned; if it is a list, the @sc{car} of that list (which should be a -number) is returned. -@end defun - -@defvar current-prefix-arg -This variable holds the raw prefix argument for the @emph{current} -command. Commands may examine it directly, but the usual way to access -it is with @code{(interactive "P")}. -@end defvar - -@defvar prefix-arg -The value of this variable is the raw prefix argument for the -@emph{next} editing command. Commands that specify prefix arguments for -the following command work by setting this variable. -@end defvar - - Do not call the functions @code{universal-argument}, -@code{digit-argument}, or @code{negative-argument} unless you intend to -let the user enter the prefix argument for the @emph{next} command. - -@deffn Command universal-argument -This command reads input and specifies a prefix argument for the -following command. Don't call this command yourself unless you know -what you are doing. -@end deffn - -@deffn Command digit-argument arg -This command adds to the prefix argument for the following command. The -argument @var{arg} is the raw prefix argument as it was before this -command; it is used to compute the updated prefix argument. Don't call -this command yourself unless you know what you are doing. -@end deffn - -@deffn Command negative-argument arg -This command adds to the numeric argument for the next command. The -argument @var{arg} is the raw prefix argument as it was before this -command; its value is negated to form the new prefix argument. Don't -call this command yourself unless you know what you are doing. -@end deffn - -@node Recursive Editing -@section Recursive Editing -@cindex recursive command loop -@cindex recursive editing level -@cindex command loop, recursive - - The Emacs command loop is entered automatically when Emacs starts up. -This top-level invocation of the command loop never exits; it keeps -running as long as Emacs does. Lisp programs can also invoke the -command loop. Since this makes more than one activation of the command -loop, we call it @dfn{recursive editing}. A recursive editing level has -the effect of suspending whatever command invoked it and permitting the -user to do arbitrary editing before resuming that command. - - The commands available during recursive editing are the same ones -available in the top-level editing loop and defined in the keymaps. -Only a few special commands exit the recursive editing level; the others -return to the recursive editing level when they finish. (The special -commands for exiting are always available, but they do nothing when -recursive editing is not in progress.) - - All command loops, including recursive ones, set up all-purpose error -handlers so that an error in a command run from the command loop will -not exit the loop. - -@cindex minibuffer input - Minibuffer input is a special kind of recursive editing. It has a few -special wrinkles, such as enabling display of the minibuffer and the -minibuffer window, but fewer than you might suppose. Certain keys -behave differently in the minibuffer, but that is only because of the -minibuffer's local map; if you switch windows, you get the usual Emacs -commands. - -@cindex @code{throw} example -@kindex exit -@cindex exit recursive editing -@cindex aborting - To invoke a recursive editing level, call the function -@code{recursive-edit}. This function contains the command loop; it also -contains a call to @code{catch} with tag @code{exit}, which makes it -possible to exit the recursive editing level by throwing to @code{exit} -(@pxref{Catch and Throw}). If you throw a value other than @code{t}, -then @code{recursive-edit} returns normally to the function that called -it. The command @kbd{C-M-c} (@code{exit-recursive-edit}) does this. -Throwing a @code{t} value causes @code{recursive-edit} to quit, so that -control returns to the command loop one level up. This is called -@dfn{aborting}, and is done by @kbd{C-]} (@code{abort-recursive-edit}). - - Most applications should not use recursive editing, except as part of -using the minibuffer. Usually it is more convenient for the user if you -change the major mode of the current buffer temporarily to a special -major mode, which has a command to go back to the previous mode. (The -@kbd{e} command in Rmail uses this technique.) Or, if you wish to give -the user different text to edit ``recursively'', create and select a new -buffer in a special mode. In this mode, define a command to complete -the processing and go back to the previous buffer. (The @kbd{m} command -in Rmail does this.) - - Recursive edits are useful in debugging. You can insert a call to -@code{debug} into a function definition as a sort of breakpoint, so that -you can look around when the function gets there. @code{debug} invokes -a recursive edit but also provides the other features of the debugger. - - Recursive editing levels are also used when you type @kbd{C-r} in -@code{query-replace} or use @kbd{C-x q} (@code{kbd-macro-query}). - -@defun recursive-edit -@cindex suspend evaluation -This function invokes the editor command loop. It is called -automatically by the initialization of Emacs, to let the user begin -editing. When called from a Lisp program, it enters a recursive editing -level. - - In the following example, the function @code{simple-rec} first -advances point one word, then enters a recursive edit, printing out a -message in the echo area. The user can then do any editing desired, and -then type @kbd{C-M-c} to exit and continue executing @code{simple-rec}. - -@example -(defun simple-rec () - (forward-word 1) - (message "Recursive edit in progress") - (recursive-edit) - (forward-word 1)) - @result{} simple-rec -(simple-rec) - @result{} nil -@end example -@end defun - -@deffn Command exit-recursive-edit -This function exits from the innermost recursive edit (including -minibuffer input). Its definition is effectively @code{(throw 'exit -nil)}. -@end deffn - -@deffn Command abort-recursive-edit -This function aborts the command that requested the innermost recursive -edit (including minibuffer input), by signaling @code{quit} -after exiting the recursive edit. Its definition is effectively -@code{(throw 'exit t)}. @xref{Quitting}. -@end deffn - -@deffn Command top-level -This function exits all recursive editing levels; it does not return a -value, as it jumps completely out of any computation directly back to -the main command loop. -@end deffn - -@defun recursion-depth -This function returns the current depth of recursive edits. When no -recursive edit is active, it returns 0. -@end defun - -@node Disabling Commands -@section Disabling Commands -@cindex disabled command - - @dfn{Disabling a command} marks the command as requiring user -confirmation before it can be executed. Disabling is used for commands -which might be confusing to beginning users, to prevent them from using -the commands by accident. - -@kindex disabled - The low-level mechanism for disabling a command is to put a -non-@code{nil} @code{disabled} property on the Lisp symbol for the -command. These properties are normally set up by the user's -@file{.emacs} file with Lisp expressions such as this: - -@example -(put 'upcase-region 'disabled t) -@end example - -@noindent -For a few commands, these properties are present by default and may be -removed by the @file{.emacs} file. - - If the value of the @code{disabled} property is a string, the message -saying the command is disabled includes that string. For example: - -@example -(put 'delete-region 'disabled - "Text deleted this way cannot be yanked back!\n") -@end example - - @xref{Disabling,,, emacs, The GNU Emacs Manual}, for the details on -what happens when a disabled command is invoked interactively. -Disabling a command has no effect on calling it as a function from Lisp -programs. - -@deffn Command enable-command command -Allow @var{command} to be executed without special confirmation from now -on, and optionally alter the user's @file{.emacs} file so that this will -apply to future sessions. -@end deffn - -@deffn Command disable-command command -Require special confirmation to execute @var{command} from now on, and -optionally alter the user's @file{.emacs} file so that this will apply -to future sessions. -@end deffn - -@defvar disabled-command-hook -This normal hook is run instead of a disabled command, when the user -invokes the disabled command interactively. The hook functions can use -@code{this-command-keys} to determine what the user typed to run the -command, and thus find the command itself. - -By default, @code{disabled-command-hook} contains a function that asks -the user whether to proceed. -@end defvar - -@node Command History -@section Command History -@cindex command history -@cindex complex command -@cindex history of commands - - The command loop keeps a history of the complex commands that have -been executed, to make it convenient to repeat these commands. A -@dfn{complex command} is one for which the interactive argument reading -uses the minibuffer. This includes any @kbd{M-x} command, any -@kbd{M-ESC} command, and any command whose @code{interactive} -specification reads an argument from the minibuffer. Explicit use of -the minibuffer during the execution of the command itself does not cause -the command to be considered complex. - -@defvar command-history -This variable's value is a list of recent complex commands, each -represented as a form to evaluate. It continues to accumulate all -complex commands for the duration of the editing session, but all but -the first (most recent) thirty elements are deleted when a garbage -collection takes place (@pxref{Garbage Collection}). - -@example -@group -command-history -@result{} ((switch-to-buffer "chistory.texi") - (describe-key "^X^[") - (visit-tags-table "~/emacs/src/") - (find-tag "repeat-complex-command")) -@end group -@end example -@end defvar - - This history list is actually a special case of minibuffer history -(@pxref{Minibuffer History}), with one special twist: the elements are -expressions rather than strings. - - There are a number of commands devoted to the editing and recall of -previous commands. The commands @code{repeat-complex-command}, and -@code{list-command-history} are described in the user manual -(@pxref{Repetition,,, emacs, The GNU Emacs Manual}). Within the -minibuffer, the history commands used are the same ones available in any -minibuffer. - -@node Keyboard Macros -@section Keyboard Macros -@cindex keyboard macros - - A @dfn{keyboard macro} is a canned sequence of input events that can -be considered a command and made the definition of a key. The Lisp -representation of a keyboard macro is a string or vector containing the -events. Don't confuse keyboard macros with Lisp macros -(@pxref{Macros}). - -@defun execute-kbd-macro macro &optional count -This function executes @var{macro} as a sequence of events. If -@var{macro} is a string or vector, then the events in it are executed -exactly as if they had been input by the user. The sequence is -@emph{not} expected to be a single key sequence; normally a keyboard -macro definition consists of several key sequences concatenated. - -If @var{macro} is a symbol, then its function definition is used in -place of @var{macro}. If that is another symbol, this process repeats. -Eventually the result should be a string or vector. If the result is -not a symbol, string, or vector, an error is signaled. - -The argument @var{count} is a repeat count; @var{macro} is executed that -many times. If @var{count} is omitted or @code{nil}, @var{macro} is -executed once. If it is 0, @var{macro} is executed over and over until it -encounters an error or a failing search. -@end defun - -@defvar last-kbd-macro -This variable is the definition of the most recently defined keyboard -macro. Its value is a string or vector, or @code{nil}. -@end defvar - -@defvar executing-macro -This variable contains the string or vector that defines the keyboard -macro that is currently executing. It is @code{nil} if no macro is -currently executing. A command can test this variable to behave -differently when run from an executing macro. Do not set this variable -yourself. -@end defvar - -@defvar defining-kbd-macro -This variable indicates whether a keyboard macro is being defined. A -command can test this variable to behave differently while a macro is -being defined. The commands @code{start-kbd-macro} and -@code{end-kbd-macro} set this variable---do not set it yourself. -@end defvar - |