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diff --git a/doc/readline.info-1 b/doc/readline.info-1 new file mode 100644 index 0000000..78bbd05 --- /dev/null +++ b/doc/readline.info-1 @@ -0,0 +1,1322 @@ +This is Info file readline.info, produced by Makeinfo-1.55 from the +input file rlman.texinfo. + + This document describes the GNU Readline Library, a utility which +aids in the consistency of user interface across discrete programs that +need to provide a command line interface. + + Copyright (C) 1988, 1991 Free Software Foundation, Inc. + + Permission is granted to make and distribute verbatim copies of this +manual provided the copyright notice and this permission notice pare +preserved on all copies. + + Permission is granted to copy and distribute modified versions of +this manual under the conditions for verbatim copying, provided that +the entire resulting derived work is distributed under the terms of a +permission notice identical to this one. + + Permission is granted to copy and distribute translations of this +manual into another language, under the above conditions for modified +versions, except that this permission notice may be stated in a +translation approved by the Foundation. + + +File: readline.info, Node: Top, Next: Command Line Editing, Prev: (DIR), Up: (DIR) + +GNU Readline Library +******************** + + This document describes the GNU Readline Library, a utility which +aids in the consistency of user interface across discrete programs that +need to provide a command line interface. + +* Menu: + +* Command Line Editing:: GNU Readline User's Manual. +* Programming with GNU Readline:: GNU Readline Programmer's Manual. +* Concept Index:: Index of concepts described in this manual. +* Function and Variable Index:: Index of externally visible functions + and variables. + + +File: readline.info, Node: Command Line Editing, Next: Programming with GNU Readline, Prev: Top, Up: Top + +Command Line Editing +******************** + + This chapter describes the basic features of the GNU command line +editing interface. + +* Menu: + +* Introduction and Notation:: Notation used in this text. +* Readline Interaction:: The minimum set of commands for editing a line. +* Readline Init File:: Customizing Readline from a user's view. +* Bindable Readline Commands:: A description of most of the Readline commands + available for binding +* Readline vi Mode:: A short description of how to make Readline + behave like the vi editor. + + +File: readline.info, Node: Introduction and Notation, Next: Readline Interaction, Up: Command Line Editing + +Introduction to Line Editing +============================ + + The following paragraphs describe the notation used to represent +keystrokes. + + The text C-k is read as `Control-K' and describes the character +produced when the Control key is depressed and the k key is struck. + + The text M-k is read as `Meta-K' and describes the character +produced when the meta key (if you have one) is depressed, and the k +key is struck. If you do not have a meta key, the identical keystroke +can be generated by typing ESC first, and then typing k. Either +process is known as "metafying" the k key. + + The text M-C-k is read as `Meta-Control-k' and describes the +character produced by "metafying" C-k. + + In addition, several keys have their own names. Specifically, DEL, +ESC, LFD, SPC, RET, and TAB all stand for themselves when seen in this +text, or in an init file (*note Readline Init File::., for more info). + + +File: readline.info, Node: Readline Interaction, Next: Readline Init File, Prev: Introduction and Notation, Up: Command Line Editing + +Readline Interaction +==================== + + Often during an interactive session you type in a long line of text, +only to notice that the first word on the line is misspelled. The +Readline library gives you a set of commands for manipulating the text +as you type it in, allowing you to just fix your typo, and not forcing +you to retype the majority of the line. Using these editing commands, +you move the cursor to the place that needs correction, and delete or +insert the text of the corrections. Then, when you are satisfied with +the line, you simply press RETURN. You do not have to be at the end of +the line to press RETURN; the entire line is accepted regardless of the +location of the cursor within the line. + +* Menu: + +* Readline Bare Essentials:: The least you need to know about Readline. +* Readline Movement Commands:: Moving about the input line. +* Readline Killing Commands:: How to delete text, and how to get it back! +* Readline Arguments:: Giving numeric arguments to commands. + + +File: readline.info, Node: Readline Bare Essentials, Next: Readline Movement Commands, Up: Readline Interaction + +Readline Bare Essentials +------------------------ + + In order to enter characters into the line, simply type them. The +typed character appears where the cursor was, and then the cursor moves +one space to the right. If you mistype a character, you can use your +erase character to back up and delete the mistyped character. + + Sometimes you may miss typing a character that you wanted to type, +and not notice your error until you have typed several other +characters. In that case, you can type C-b to move the cursor to the +left, and then correct your mistake. Afterwards, you can move the +cursor to the right with C-f. + + When you add text in the middle of a line, you will notice that +characters to the right of the cursor are `pushed over' to make room +for the text that you have inserted. Likewise, when you delete text +behind the cursor, characters to the right of the cursor are `pulled +back' to fill in the blank space created by the removal of the text. A +list of the basic bare essentials for editing the text of an input line +follows. + +C-b + Move back one character. + +C-f + Move forward one character. + +DEL + Delete the character to the left of the cursor. + +C-d + Delete the character underneath the cursor. + +Printing characters + Insert the character into the line at the cursor. + +C-_ + Undo the last thing that you did. You can undo all the way back + to an empty line. + + +File: readline.info, Node: Readline Movement Commands, Next: Readline Killing Commands, Prev: Readline Bare Essentials, Up: Readline Interaction + +Readline Movement Commands +-------------------------- + + The above table describes the most basic possible keystrokes that +you need in order to do editing of the input line. For your +convenience, many other commands have been added in addition to C-b, +C-f, C-d, and DEL. Here are some commands for moving more rapidly +about the line. + +C-a + Move to the start of the line. + +C-e + Move to the end of the line. + +M-f + Move forward a word. + +M-b + Move backward a word. + +C-l + Clear the screen, reprinting the current line at the top. + + Notice how C-f moves forward a character, while M-f moves forward a +word. It is a loose convention that control keystrokes operate on +characters while meta keystrokes operate on words. + + +File: readline.info, Node: Readline Killing Commands, Next: Readline Arguments, Prev: Readline Movement Commands, Up: Readline Interaction + +Readline Killing Commands +------------------------- + + "Killing" text means to delete the text from the line, but to save +it away for later use, usually by "yanking" (re-inserting) it back into +the line. If the description for a command says that it `kills' text, +then you can be sure that you can get the text back in a different (or +the same) place later. + + When you use a kill command, the text is saved in a "kill-ring". +Any number of consecutive kills save all of the killed text together, so +that when you yank it back, you get it all. The kill ring is not line +specific; the text that you killed on a previously typed line is +available to be yanked back later, when you are typing another line. + + Here is the list of commands for killing text. + +C-k + Kill the text from the current cursor position to the end of the + line. + +M-d + Kill from the cursor to the end of the current word, or if between + words, to the end of the next word. + +M-DEL + Kill from the cursor the start of the previous word, or if between + words, to the start of the previous word. + +C-w + Kill from the cursor to the previous whitespace. This is + different than M-DEL because the word boundaries differ. + + And, here is how to "yank" the text back into the line. Yanking +means to copy the most-recently-killed text from the kill buffer. + +C-y + Yank the most recently killed text back into the buffer at the + cursor. + +M-y + Rotate the kill-ring, and yank the new top. You can only do this + if the prior command is C-y or M-y. + + +File: readline.info, Node: Readline Arguments, Prev: Readline Killing Commands, Up: Readline Interaction + +Readline Arguments +------------------ + + You can pass numeric arguments to Readline commands. Sometimes the +argument acts as a repeat count, other times it is the sign of the +argument that is significant. If you pass a negative argument to a +command which normally acts in a forward direction, that command will +act in a backward direction. For example, to kill text back to the +start of the line, you might type M- C-k. + + The general way to pass numeric arguments to a command is to type +meta digits before the command. If the first `digit' you type is a +minus sign (-), then the sign of the argument will be negative. Once +you have typed one meta digit to get the argument started, you can type +the remainder of the digits, and then the command. For example, to give +the C-d command an argument of 10, you could type M-1 0 C-d. + + +File: readline.info, Node: Readline Init File, Next: Bindable Readline Commands, Prev: Readline Interaction, Up: Command Line Editing + +Readline Init File +================== + + Although the Readline library comes with a set of Emacs-like +keybindings installed by default, it is possible that you would like to +use a different set of keybindings. You can customize programs that +use Readline by putting commands in an "init" file in your home +directory. The name of this file is taken from the value of the +environment variable `INPUTRC'. If that variable is unset, the default +is `~/.inputrc'. + + When a program which uses the Readline library starts up, the init +file is read, and the key bindings are set. + + In addition, the `C-x C-r' command re-reads this init file, thus +incorporating any changes that you might have made to it. + +* Menu: + +* Readline Init Syntax:: Syntax for the commands in the inputrc file. +* Conditional Init Constructs:: Conditional key bindings in the inputrc file. + + +File: readline.info, Node: Readline Init Syntax, Next: Conditional Init Constructs, Up: Readline Init File + +Readline Init Syntax +-------------------- + + There are only a few basic constructs allowed in the Readline init +file. Blank lines are ignored. Lines beginning with a # are comments. +Lines beginning with a $ indicate conditional constructs (*note +Conditional Init Constructs::.). Other lines denote variable settings +and key bindings. + +Variable Settings + You can change the state of a few variables in Readline by using + the `set' command within the init file. Here is how you would + specify that you wish to use `vi' line editing commands: + + set editing-mode vi + + Right now, there are only a few variables which can be set; so + few, in fact, that we just list them here: + + `editing-mode' + The `editing-mode' variable controls which editing mode you + are using. By default, Readline starts up in Emacs editing + mode, where the keystrokes are most similar to Emacs. This + variable can be set to either `emacs' or `vi'. + + `horizontal-scroll-mode' + This variable can be set to either `On' or `Off'. Setting it + to `On' means that the text of the lines that you edit will + scroll horizontally on a single screen line when they are + longer than the width of the screen, instead of wrapping onto + a new screen line. By default, this variable is set to `Off'. + + `mark-modified-lines' + This variable, when set to `On', says to display an asterisk + (`*') at the start of history lines which have been modified. + This variable is `off' by default. + + `bell-style' + Controls what happens when Readline wants to ring the + terminal bell. If set to `none', Readline never rings the + bell. If set to `visible', Readline uses a visible bell if + one is available. If set to `audible' (the default), + Readline attempts to ring the terminal's bell. + + `comment-begin' + The string to insert at the beginning of the line when the + `vi-comment' command is executed. The default value is `"#"'. + + `meta-flag' + If set to `on', Readline will enable eight-bit input (it will + not strip the eighth bit from the characters it reads), + regardless of what the terminal claims it can support. The + default value is `off'. + + `convert-meta' + If set to `on', Readline will convert characters with the + eigth bit set to an ASCII key sequence by stripping the eigth + bit and prepending an ESC character, converting them to a + meta-prefixed key sequence. The default value is `on'. + + `output-meta' + If set to `on', Readline will display characters with the + eighth bit set directly rather than as a meta-prefixed escape + sequence. The default is `off'. + + `completion-query-items' + The number of possible completions that determines when the + user is asked whether he wants to see the list of + possibilities. If the number of possible completions is + greater than this value, Readline will ask the user whether + or not he wishes to view them; otherwise, they are simply + listed. The default limit is `100'. + + `keymap' + Sets Readline's idea of the current keymap for key binding + commands. Acceptable `keymap' names are `emacs', + `emacs-standard', `emacs-meta', `emacs-ctlx', `vi', `vi-move', + `vi-command', and `vi-insert'. `vi' is equivalent to + `vi-command'; `emacs' is equivalent to `emacs-standard'. The + default value is `emacs'. The value of the `editing-mode' + variable also affects the default keymap. + + `show-all-if-ambiguous' + This alters the default behavior of the completion functions. + If set to `on', words which have more than one possible + completion cause the matches to be listed immediately instead + of ringing the bell. The default value is `off'. + + `expand-tilde' + If set to `on', tilde expansion is performed when Readline + attempts word completion. The default is `off'. + +Key Bindings + The syntax for controlling key bindings in the init file is + simple. First you have to know the name of the command that you + want to change. The following pages contain tables of the command + name, the default keybinding, and a short description of what the + command does. + + Once you know the name of the command, simply place the name of + the key you wish to bind the command to, a colon, and then the + name of the command on a line in the init file. The name of the + key can be expressed in different ways, depending on which is most + comfortable for you. + + KEYNAME: FUNCTION-NAME or MACRO + KEYNAME is the name of a key spelled out in English. For + example: + Control-u: universal-argument + Meta-Rubout: backward-kill-word + Control-o: ">&output" + + In the above example, `C-u' is bound to the function + `universal-argument', and `C-o' is bound to run the macro + expressed on the right hand side (that is, to insert the text + `>&output' into the line). + + "KEYSEQ": FUNCTION-NAME or MACRO + KEYSEQ differs from KEYNAME above in that strings denoting an + entire key sequence can be specified, by placing the key + sequence in double quotes. Some GNU Emacs style key escapes + can be used, as in the following example, but the special + character names are not recognized. + + "\C-u": universal-argument + "\C-x\C-r": re-read-init-file + "\e[11~": "Function Key 1" + + In the above example, `C-u' is bound to the function + `universal-argument' (just as it was in the first example), + `C-x C-r' is bound to the function `re-read-init-file', and + `ESC [ 1 1 ~' is bound to insert the text `Function Key 1'. + The following escape sequences are available when specifying + key sequences: + + ``\C-'' + control prefix + + ``\M-'' + meta prefix + + ``\e'' + an escape character + + ``\\'' + backslash + + ``\"'' + " + + ``\''' + ' + + When entering the text of a macro, single or double quotes + should be used to indicate a macro definition. Unquoted text + is assumed to be a function name. Backslash will quote any + character in the macro text, including " and '. For example, + the following binding will make `C-x \' insert a single \ + into the line: + "\C-x\\": "\\" + + +File: readline.info, Node: Conditional Init Constructs, Prev: Readline Init Syntax, Up: Readline Init File + +Conditional Init Constructs +--------------------------- + + Readline implements a facility similar in spirit to the conditional +compilation features of the C preprocessor which allows key bindings +and variable settings to be performed as the result of tests. There +are three parser directives used. + +`$if' + The `$if' construct allows bindings to be made based on the + editing mode, the terminal being used, or the application using + Readline. The text of the test extends to the end of the line; no + characters are required to isolate it. + + `mode' + The `mode=' form of the `$if' directive is used to test + whether Readline is in `emacs' or `vi' mode. This may be + used in conjunction with the `set keymap' command, for + instance, to set bindings in the `emacs-standard' and + `emacs-ctlx' keymaps only if Readline is starting out in + `emacs' mode. + + `term' + The `term=' form may be used to include terminal-specific key + bindings, perhaps to bind the key sequences output by the + terminal's function keys. The word on the right side of the + `=' is tested against the full name of the terminal and the + portion of the terminal name before the first `-'. This + allows SUN to match both SUN and SUN-CMD, for instance. + + `application' + The APPLICATION construct is used to include + application-specific settings. Each program using the + Readline library sets the APPLICATION NAME, and you can test + for it. This could be used to bind key sequences to + functions useful for a specific program. For instance, the + following command adds a key sequence that quotes the current + or previous word in Bash: + $if bash + # Quote the current or previous word + "\C-xq": "\eb\"\ef\"" + $endif + +`$endif' + This command, as you saw in the previous example, terminates an + `$if' command. + +`$else' + Commands in this branch of the `$if' directive are executed if the + test fails. + + +File: readline.info, Node: Bindable Readline Commands, Next: Readline vi Mode, Prev: Readline Init File, Up: Command Line Editing + +Bindable Readline Commands +========================== + +* Menu: + +* Commands For Moving:: Moving about the line. +* Commands For History:: Getting at previous lines. +* Commands For Text:: Commands for changing text. +* Commands For Killing:: Commands for killing and yanking. +* Numeric Arguments:: Specifying numeric arguments, repeat counts. +* Commands For Completion:: Getting Readline to do the typing for you. +* Keyboard Macros:: Saving and re-executing typed characters +* Miscellaneous Commands:: Other miscellaneous commands. + + +File: readline.info, Node: Commands For Moving, Next: Commands For History, Up: Bindable Readline Commands + +Commands For Moving +------------------- + +`beginning-of-line (C-a)' + Move to the start of the current line. + +`end-of-line (C-e)' + Move to the end of the line. + +`forward-char (C-f)' + Move forward a character. + +`backward-char (C-b)' + Move back a character. + +`forward-word (M-f)' + Move forward to the end of the next word. Words are composed of + letters and digits. + +`backward-word (M-b)' + Move back to the start of this, or the previous, word. Words are + composed of letters and digits. + +`clear-screen (C-l)' + Clear the screen and redraw the current line, leaving the current + line at the top of the screen. + +`redraw-current-line ()' + Refresh the current line. By default, this is unbound. + + +File: readline.info, Node: Commands For History, Next: Commands For Text, Prev: Commands For Moving, Up: Bindable Readline Commands + +Commands For Manipulating The History +------------------------------------- + +`accept-line (Newline, Return)' + Accept the line regardless of where the cursor is. If this line is + non-empty, add it to the history list. If this line was a history + line, then restore the history line to its original state. + +`previous-history (C-p)' + Move `up' through the history list. + +`next-history (C-n)' + Move `down' through the history list. + +`beginning-of-history (M-<)' + Move to the first line in the history. + +`end-of-history (M->)' + Move to the end of the input history, i.e., the line you are + entering. + +`reverse-search-history (C-r)' + Search backward starting at the current line and moving `up' + through the history as necessary. This is an incremental search. + +`forward-search-history (C-s)' + Search forward starting at the current line and moving `down' + through the the history as necessary. This is an incremental + search. + +`non-incremental-reverse-search-history (M-p)' + Search backward starting at the current line and moving `up' + through the history as necessary using a non-incremental search + for a string supplied by the user. + +`non-incremental-forward-search-history (M-n)' + Search forward starting at the current line and moving `down' + through the the history as necessary using a non-incremental search + for a string supplied by the user. + +`history-search-forward ()' + Search forward through the history for the string of characters + between the start of the current line and the current point. This + is a non-incremental search. By default, this command is unbound. + +`history-search-backward ()' + Search backward through the history for the string of characters + between the start of the current line and the current point. This + is a non-incremental search. By default, this command is unbound. + +`yank-nth-arg (M-C-y)' + Insert the first argument to the previous command (usually the + second word on the previous line). With an argument N, insert the + Nth word from the previous command (the words in the previous + command begin with word 0). A negative argument inserts the Nth + word from the end of the previous command. + +`yank-last-arg (M-., M-_)' + Insert last argument to the previous command (the last word on the + previous line). With an argument, behave exactly like + `yank-nth-arg'. + + +File: readline.info, Node: Commands For Text, Next: Commands For Killing, Prev: Commands For History, Up: Bindable Readline Commands + +Commands For Changing Text +-------------------------- + +`delete-char (C-d)' + Delete the character under the cursor. If the cursor is at the + beginning of the line, there are no characters in the line, and + the last character typed was not C-d, then return EOF. + +`backward-delete-char (Rubout)' + Delete the character behind the cursor. A numeric arg says to kill + the characters instead of deleting them. + +`quoted-insert (C-q, C-v)' + Add the next character that you type to the line verbatim. This is + how to insert key sequences like C-q, for example. + +`tab-insert (M-TAB)' + Insert a tab character. + +`self-insert (a, b, A, 1, !, ...)' + Insert yourself. + +`transpose-chars (C-t)' + Drag the character before the cursor forward over the character at + the cursor, moving the cursor forward as well. If the insertion + point is at the end of the line, then this transposes the last two + characters of the line. Negative argumentss don't work. + +`transpose-words (M-t)' + Drag the word behind the cursor past the word in front of the + cursor moving the cursor over that word as well. + +`upcase-word (M-u)' + Uppercase the current (or following) word. With a negative + argument, do the previous word, but do not move the cursor. + +`downcase-word (M-l)' + Lowercase the current (or following) word. With a negative + argument, do the previous word, but do not move the cursor. + +`capitalize-word (M-c)' + Capitalize the current (or following) word. With a negative + argument, do the previous word, but do not move the cursor. + + +File: readline.info, Node: Commands For Killing, Next: Numeric Arguments, Prev: Commands For Text, Up: Bindable Readline Commands + +Killing And Yanking +------------------- + +`kill-line (C-k)' + Kill the text from the current cursor position to the end of the + line. + +`backward-kill-line (C-x Rubout)' + Kill backward to the beginning of the line. + +`unix-line-discard (C-u)' + Kill backward from the cursor to the beginning of the current line. + Save the killed text on the kill-ring. + +`kill-whole-line ()' + Kill all characters on the current line, no matter where the + cursor is. By default, this is unbound. + +`kill-word (M-d)' + Kill from the cursor to the end of the current word, or if between + words, to the end of the next word. Word boundaries are the same + as `forward-word'. + +`backward-kill-word (M-DEL)' + Kill the word behind the cursor. Word boundaries are the same as + `backward-word'. + +`unix-word-rubout (C-w)' + Kill the word behind the cursor, using white space as a word + boundary. The killed text is saved on the kill-ring. + +`delete-horizontal-space ()' + Delete all spaces and tabs around point. By default, this is + unbound. + +`yank (C-y)' + Yank the top of the kill ring into the buffer at the current + cursor position. + +`yank-pop (M-y)' + Rotate the kill-ring, and yank the new top. You can only do this + if the prior command is yank or yank-pop. + + +File: readline.info, Node: Numeric Arguments, Next: Commands For Completion, Prev: Commands For Killing, Up: Bindable Readline Commands + +Specifying Numeric Arguments +---------------------------- + +`digit-argument (M-0, M-1, ... M--)' + Add this digit to the argument already accumulating, or start a new + argument. M- starts a negative argument. + +`universal-argument ()' + Each time this is executed, the argument count is multiplied by + four. The argument count is initially one, so executing this + function the first time makes the argument count four. By + default, this is not bound to a key. + + +File: readline.info, Node: Commands For Completion, Next: Keyboard Macros, Prev: Numeric Arguments, Up: Bindable Readline Commands + +Letting Readline Type For You +----------------------------- + +`complete (TAB)' + Attempt to do completion on the text before the cursor. This is + application-specific. Generally, if you are typing a filename + argument, you can do filename completion; if you are typing a + command, you can do command completion, if you are typing in a + symbol to GDB, you can do symbol name completion, if you are + typing in a variable to Bash, you can do variable name completion, + and so on. + +`possible-completions (M-?)' + List the possible completions of the text before the cursor. + +`insert-completions ()' + Insert all completions of the text before point that would have + been generated by `possible-completions'. By default, this is not + bound to a key. + + +File: readline.info, Node: Keyboard Macros, Next: Miscellaneous Commands, Prev: Commands For Completion, Up: Bindable Readline Commands + +Keyboard Macros +--------------- + +`start-kbd-macro (C-x ()' + Begin saving the characters typed into the current keyboard macro. + +`end-kbd-macro (C-x ))' + Stop saving the characters typed into the current keyboard macro + and save the definition. + +`call-last-kbd-macro (C-x e)' + Re-execute the last keyboard macro defined, by making the + characters in the macro appear as if typed at the keyboard. + + +File: readline.info, Node: Miscellaneous Commands, Prev: Keyboard Macros, Up: Bindable Readline Commands + +Some Miscellaneous Commands +--------------------------- + +`re-read-init-file (C-x C-r)' + Read in the contents of your init file, and incorporate any + bindings or variable assignments found there. + +`abort (C-g)' + Abort the current editing command and ring the terminal's bell + (subject to the setting of `bell-style'). + +`do-uppercase-version (M-a, M-b, ...)' + Run the command that is bound to the corresoponding uppercase + character. + +`prefix-meta (ESC)' + Make the next character that you type be metafied. This is for + people without a meta key. Typing `ESC f' is equivalent to typing + `M-f'. + +`undo (C-_, C-x C-u)' + Incremental undo, separately remembered for each line. + +`revert-line (M-r)' + Undo all changes made to this line. This is like typing the `undo' + command enough times to get back to the beginning. + +`tilde-expand (M-~)' + Perform tilde expansion on the current word. + +`dump-functions ()' + Print all of the functions and their key bindings to the readline + output stream. If a numeric argument is supplied, the output is + formatted in such a way that it can be made part of an INPUTRC + file. + + +File: readline.info, Node: Readline vi Mode, Prev: Bindable Readline Commands, Up: Command Line Editing + +Readline vi Mode +================ + + While the Readline library does not have a full set of `vi' editing +functions, it does contain enough to allow simple editing of the line. +The Readline `vi' mode behaves as specified in the Posix 1003.2 +standard. + + In order to switch interactively between `Emacs' and `Vi' editing +modes, use the command M-C-j (toggle-editing-mode). The Readline +default is `emacs' mode. + + When you enter a line in `vi' mode, you are already placed in +`insertion' mode, as if you had typed an `i'. Pressing ESC switches +you into `command' mode, where you can edit the text of the line with +the standard `vi' movement keys, move to previous history lines with +`k', and following lines with `j', and so forth. + + This document describes the GNU Readline Library, a utility for +aiding in the consitency of user interface across discrete programs +that need to provide a command line interface. + + Copyright (C) 1988, 1994 Free Software Foundation, Inc. + + Permission is granted to make and distribute verbatim copies of this +manual provided the copyright notice and this permission notice pare +preserved on all copies. + + Permission is granted to copy and distribute modified versions of +this manual under the conditions for verbatim copying, provided that +the entire resulting derived work is distributed under the terms of a +permission notice identical to this one. + + Permission is granted to copy and distribute translations of this +manual into another language, under the above conditions for modified +versions, except that this permission notice may be stated in a +translation approved by the Foundation. + + +File: readline.info, Node: Programming with GNU Readline, Next: Concept Index, Prev: Command Line Editing, Up: Top + +Programming with GNU Readline +***************************** + + This chapter describes the interface between the GNU Readline +Library and other programs. If you are a programmer, and you wish to +include the features found in GNU Readline such as completion, line +editing, and interactive history manipulation in your own programs, +this section is for you. + +* Menu: + +* Basic Behavior:: Using the default behavior of Readline. +* Custom Functions:: Adding your own functions to Readline. +* Readline Convenience Functions:: Functions which Readline supplies to + aid in writing your own +* Custom Completers:: Supplanting or supplementing Readline's + completion functions. + + +File: readline.info, Node: Basic Behavior, Next: Custom Functions, Up: Programming with GNU Readline + +Basic Behavior +============== + + Many programs provide a command line interface, such as `mail', +`ftp', and `sh'. For such programs, the default behaviour of Readline +is sufficient. This section describes how to use Readline in the +simplest way possible, perhaps to replace calls in your code to +`gets()' or `fgets ()'. + + The function `readline ()' prints a prompt and then reads and returns +a single line of text from the user. The line `readline' returns is +allocated with `malloc ()'; you should `free ()' the line when you are +done with it. The declaration for `readline' in ANSI C is + + `char *readline (char *PROMPT);' + +So, one might say + `char *line = readline ("Enter a line: ");' + +in order to read a line of text from the user. The line returned has +the final newline removed, so only the text remains. + + If `readline' encounters an `EOF' while reading the line, and the +line is empty at that point, then `(char *)NULL' is returned. +Otherwise, the line is ended just as if a newline had been typed. + + If you want the user to be able to get at the line later, (with C-p +for example), you must call `add_history ()' to save the line away in a +"history" list of such lines. + + `add_history (line)'; + +For full details on the GNU History Library, see the associated manual. + + It is preferable to avoid saving empty lines on the history list, +since users rarely have a burning need to reuse a blank line. Here is +a function which usefully replaces the standard `gets ()' library +function, and has the advantage of no static buffer to overflow: + + /* A static variable for holding the line. */ + static char *line_read = (char *)NULL; + + /* Read a string, and return a pointer to it. Returns NULL on EOF. */ + char * + rl_gets () + { + /* If the buffer has already been allocated, return the memory + to the free pool. */ + if (line_read) + { + free (line_read); + line_read = (char *)NULL; + } + + /* Get a line from the user. */ + line_read = readline (""); + + /* If the line has any text in it, save it on the history. */ + if (line_read && *line_read) + add_history (line_read); + + return (line_read); + } + + This function gives the user the default behaviour of TAB +completion: completion on file names. If you do not want Readline to +complete on filenames, you can change the binding of the TAB key with +`rl_bind_key ()'. + + `int rl_bind_key (int KEY, int (*FUNCTION)());' + + `rl_bind_key ()' takes two arguments: KEY is the character that you +want to bind, and FUNCTION is the address of the function to call when +KEY is pressed. Binding TAB to `rl_insert ()' makes TAB insert itself. +`rl_bind_key ()' returns non-zero if KEY is not a valid ASCII character +code (between 0 and 255). + + Thus, to disable the default TAB behavior, the following suffices: + `rl_bind_key ('\t', rl_insert);' + + This code should be executed once at the start of your program; you +might write a function called `initialize_readline ()' which performs +this and other desired initializations, such as installing custom +completers (*note Custom Completers::.). + + +File: readline.info, Node: Custom Functions, Next: Readline Convenience Functions, Prev: Basic Behavior, Up: Programming with GNU Readline + +Custom Functions +================ + + Readline provides many functions for manipulating the text of the +line, but it isn't possible to anticipate the needs of all programs. +This section describes the various functions and variables defined +within the Readline library which allow a user program to add +customized functionality to Readline. + +* Menu: + +* The Function Type:: C declarations to make code readable. +* Function Writing:: Variables and calling conventions. + + +File: readline.info, Node: The Function Type, Next: Function Writing, Up: Custom Functions + +The Function Type +----------------- + + For readabilty, we declare a new type of object, called "Function". +A `Function' is a C function which returns an `int'. The type +declaration for `Function' is: + +`typedef int Function ();' + + The reason for declaring this new type is to make it easier to write +code describing pointers to C functions. Let us say we had a variable +called FUNC which was a pointer to a function. Instead of the classic +C declaration + + `int (*)()func;' + +we may write + + `Function *func;' + +Similarly, there are + + typedef void VFunction (); + typedef char *CPFunction (); and + typedef char **CPPFunction (); + +for functions returning no value, `pointer to char', and `pointer to +pointer to char', respectively. + + +File: readline.info, Node: Function Writing, Prev: The Function Type, Up: Custom Functions + +Writing a New Function +---------------------- + + In order to write new functions for Readline, you need to know the +calling conventions for keyboard-invoked functions, and the names of the +variables that describe the current state of the line read so far. + + The calling sequence for a command `foo' looks like + + `foo (int count, int key)' + +where COUNT is the numeric argument (or 1 if defaulted) and KEY is the +key that invoked this function. + + It is completely up to the function as to what should be done with +the numeric argument. Some functions use it as a repeat count, some as +a flag, and others to choose alternate behavior (refreshing the current +line as opposed to refreshing the screen, for example). Some choose to +ignore it. In general, if a function uses the numeric argument as a +repeat count, it should be able to do something useful with both +negative and positive arguments. At the very least, it should be aware +that it can be passed a negative argument. + + - Variable: char * rl_line_buffer + This is the line gathered so far. You are welcome to modify the + contents of the line, but see *Note Allowing Undoing::. + + - Variable: int rl_point + The offset of the current cursor position in `rl_line_buffer' (the + *point*). + + - Variable: int rl_end + The number of characters present in `rl_line_buffer'. When + `rl_point' is at the end of the line, `rl_point' and `rl_end' are + equal. + + - Variable: int rl_mark + The mark (saved position) in the current line. If set, the mark + and point define a *region*. + + - Variable: int rl_done + Setting this to a non-zero value causes Readline to return the + current line immediately. + + - Variable: int rl_pending_input + Setting this to a value makes it the next keystroke read. This is + a way to stuff a single character into the input stream. + + - Variable: char * rl_prompt + The prompt Readline uses. This is set from the argument to + `readline ()', and should not be assigned to directly. + + - Variable: char * rl_terminal_name + The terminal type, used for initialization. + + - Variable: char * rl_readline_name + This variable is set to a unique name by each application using + Readline. The value allows conditional parsing of the inputrc file + (*note Conditional Init Constructs::.). + + - Variable: FILE * rl_instream + The stdio stream from which Readline reads input. + + - Variable: FILE * rl_outstream + The stdio stream to which Readline performs output. + + - Variable: Function * rl_startup_hook + If non-zero, this is the address of a function to call just before + `readline' prints the first prompt. + + +File: readline.info, Node: Readline Convenience Functions, Next: Custom Completers, Prev: Custom Functions, Up: Programming with GNU Readline + +Readline Convenience Functions +============================== + +* Menu: + +* Function Naming:: How to give a function you write a name. +* Keymaps:: Making keymaps. +* Binding Keys:: Changing Keymaps. +* Associating Function Names and Bindings:: Translate function names to + key sequences. +* Allowing Undoing:: How to make your functions undoable. +* Redisplay:: Functions to control line display. +* Modifying Text:: Functions to modify `rl_line_buffer'. +* Utility Functions:: Generally useful functions and hooks. + + +File: readline.info, Node: Function Naming, Next: Keymaps, Up: Readline Convenience Functions + +Naming a Function +----------------- + + The user can dynamically change the bindings of keys while using +Readline. This is done by representing the function with a descriptive +name. The user is able to type the descriptive name when referring to +the function. Thus, in an init file, one might find + + Meta-Rubout: backward-kill-word + + This binds the keystroke Meta-Rubout to the function *descriptively* +named `backward-kill-word'. You, as the programmer, should bind the +functions you write to descriptive names as well. Readline provides a +function for doing that: + + - Function: int rl_add_defun (char *name, Function *function, int key) + Add NAME to the list of named functions. Make FUNCTION be the + function that gets called. If KEY is not -1, then bind it to + FUNCTION using `rl_bind_key ()'. + + Using this function alone is sufficient for most applications. It is +the recommended way to add a few functions to the default functions that +Readline has built in. If you need to do something other than adding a +function to Readline, you may need to use the underlying functions +described below. + + +File: readline.info, Node: Keymaps, Next: Binding Keys, Prev: Function Naming, Up: Readline Convenience Functions + +Selecting a Keymap +------------------ + + Key bindings take place on a "keymap". The keymap is the +association between the keys that the user types and the functions that +get run. You can make your own keymaps, copy existing keymaps, and tell +Readline which keymap to use. + + - Function: Keymap rl_make_bare_keymap () + Returns a new, empty keymap. The space for the keymap is + allocated with `malloc ()'; you should `free ()' it when you are + done. + + - Function: Keymap rl_copy_keymap (Keymap map) + Return a new keymap which is a copy of MAP. + + - Function: Keymap rl_make_keymap () + Return a new keymap with the printing characters bound to + rl_insert, the lowercase Meta characters bound to run their + equivalents, and the Meta digits bound to produce numeric + arguments. + + - Function: void rl_discard_keymap (Keymap keymap) + Free the storage associated with KEYMAP. + + Readline has several internal keymaps. These functions allow you to +change which keymap is active. + + - Function: Keymap rl_get_keymap () + Returns the currently active keymap. + + - Function: void rl_set_keymap (Keymap keymap) + Makes KEYMAP the currently active keymap. + + - Function: Keymap rl_get_keymap_by_name (char *name) + Return the keymap matching NAME. NAME is one which would be + supplied in a `set keymap' inputrc line (*note Readline Init + File::.). + + +File: readline.info, Node: Binding Keys, Next: Associating Function Names and Bindings, Prev: Keymaps, Up: Readline Convenience Functions + +Binding Keys +------------ + + You associate keys with functions through the keymap. Readline has +several internal keymaps: `emacs_standard_keymap', `emacs_meta_keymap', +`emacs_ctlx_keymap', `vi_movement_keymap', and `vi_insertion_keymap'. +`emacs_standard_keymap' is the default, and the examples in this manual +assume that. + + These functions manage key bindings. + + - Function: int rl_bind_key (int key, Function *function) + Binds KEY to FUNCTION in the currently active keymap. Returns + non-zero in the case of an invalid KEY. + + - Function: int rl_bind_key_in_map (int key, Function *function, + Keymap map) + Bind KEY to FUNCTION in MAP. Returns non-zero in the case of an + invalid KEY. + + - Function: int rl_unbind_key (int key) + Bind KEY to the null function in the currently active keymap. + Returns non-zero in case of error. + + - Function: int rl_unbind_key_in_map (int key, Keymap map) + Bind KEY to the null function in MAP. Returns non-zero in case of + error. + + - Function: int rl_generic_bind (int type, char *keyseq, char *data, + Keymap map) + Bind the key sequence represented by the string KEYSEQ to the + arbitrary pointer DATA. TYPE says what kind of data is pointed to + by DATA; this can be a function (`ISFUNC'), a macro (`ISMACR'), or + a keymap (`ISKMAP'). This makes new keymaps as necessary. The + initial keymap in which to do bindings is MAP. + + - Function: int rl_parse_and_bind (char *line) + Parse LINE as if it had been read from the `inputrc' file and + perform any key bindings and variable assignments found (*note + Readline Init File::.). + + +File: readline.info, Node: Associating Function Names and Bindings, Next: Allowing Undoing, Prev: Binding Keys, Up: Readline Convenience Functions + +Associating Function Names and Bindings +--------------------------------------- + + These functions allow you to find out what keys invoke named +functions and the functions invoked by a particular key sequence. + + - Function: Function * rl_named_function (char *name) + Return the function with name NAME. + + - Function: Function * rl_function_of_keyseq (char *keyseq, Keymap + map, int *type) + Return the function invoked by KEYSEQ in keymap MAP. If MAP is + NULL, the current keymap is used. If TYPE is not NULL, the type + of the object is returned in it (one of `ISFUNC', `ISKMAP', or + `ISMACR'). + + - Function: char ** rl_invoking_keyseqs (Function *function) + Return an array of strings representing the key sequences used to + invoke FUNCTION in the current keymap. + + - Function: char ** rl_invoking_keyseqs_in_map (Function *function, + Keymap map) + Return an array of strings representing the key sequences used to + invoke FUNCTION in the keymap MAP. + + +File: readline.info, Node: Allowing Undoing, Next: Redisplay, Prev: Associating Function Names and Bindings, Up: Readline Convenience Functions + +Allowing Undoing +---------------- + + Supporting the undo command is a painless thing, and makes your +functions much more useful. It is certainly easy to try something if +you know you can undo it. I could use an undo function for the stock +market. + + If your function simply inserts text once, or deletes text once, and +uses `rl_insert_text ()' or `rl_delete_text ()' to do it, then undoing +is already done for you automatically. + + If you do multiple insertions or multiple deletions, or any +combination of these operations, you should group them together into +one operation. This is done with `rl_begin_undo_group ()' and +`rl_end_undo_group ()'. + + The types of events that can be undone are: + + enum undo_code { UNDO_DELETE, UNDO_INSERT, UNDO_BEGIN, UNDO_END }; + + Notice that `UNDO_DELETE' means to insert some text, and +`UNDO_INSERT' means to delete some text. That is, the undo code tells +undo what to undo, not how to undo it. `UNDO_BEGIN' and `UNDO_END' are +tags added by `rl_begin_undo_group ()' and `rl_end_undo_group ()'. + + - Function: int rl_begin_undo_group () + Begins saving undo information in a group construct. The undo + information usually comes from calls to `rl_insert_text ()' and + `rl_delete_text ()', but could be the result of calls to + `rl_add_undo ()'. + + - Function: int rl_end_undo_group () + Closes the current undo group started with `rl_begin_undo_group + ()'. There should be one call to `rl_end_undo_group ()' for each + call to `rl_begin_undo_group ()'. + + - Function: void rl_add_undo (enum undo_code what, int start, int end, + char *text) + Remember how to undo an event (according to WHAT). The affected + text runs from START to END, and encompasses TEXT. + + - Function: void free_undo_list () + Free the existing undo list. + + - Function: int rl_do_undo () + Undo the first thing on the undo list. Returns `0' if there was + nothing to undo, non-zero if something was undone. + + Finally, if you neither insert nor delete text, but directly modify +the existing text (e.g., change its case), call `rl_modifying ()' once, +just before you modify the text. You must supply the indices of the +text range that you are going to modify. + + - Function: int rl_modifying (int start, int end) + Tell Readline to save the text between START and END as a single + undo unit. It is assumed that you will subsequently modify that + text. + + +File: readline.info, Node: Redisplay, Next: Modifying Text, Prev: Allowing Undoing, Up: Readline Convenience Functions + +Redisplay +--------- + + - Function: int rl_redisplay () + Change what's displayed on the screen to reflect the current + contents of `rl_line_buffer'. + + - Function: int rl_forced_update_display () + Force the line to be updated and redisplayed, whether or not + Readline thinks the screen display is correct. + + - Function: int rl_on_new_line () + Tell the update routines that we have moved onto a new (empty) + line, usually after ouputting a newline. + + - Function: int rl_reset_line_state () + Reset the display state to a clean state and redisplay the current + line starting on a new line. + + - Function: int rl_message (va_alist) + The arguments are a string as would be supplied to `printf'. The + resulting string is displayed in the "echo area". The echo area + is also used to display numeric arguments and search strings. + + - Function: int rl_clear_message () + Clear the message in the echo area. + |