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diff --git a/runtime/doc/usr_40.txt b/runtime/doc/usr_40.txt new file mode 100644 index 0000000..21c09b4 --- /dev/null +++ b/runtime/doc/usr_40.txt @@ -0,0 +1,657 @@ +*usr_40.txt* For Vim version 8.2. Last change: 2020 Sep 02 + + VIM USER MANUAL - by Bram Moolenaar + + Make new commands + + +Vim is an extensible editor. You can take a sequence of commands you use +often and turn it into a new command. Or redefine an existing command. +Autocommands make it possible to execute commands automatically. + +|40.1| Key mapping +|40.2| Defining command-line commands +|40.3| Autocommands + + Next chapter: |usr_41.txt| Write a Vim script + Previous chapter: |usr_32.txt| The undo tree +Table of contents: |usr_toc.txt| + +============================================================================== +*40.1* Key mapping + +A simple mapping was explained in section |05.3|. The principle is that one +sequence of key strokes is translated into another sequence of key strokes. +This is a simple, yet powerful mechanism. + The simplest form is that one key is mapped to a sequence of keys. Since +the function keys, except <F1>, have no predefined meaning in Vim, these are +good choices to map. Example: > + + :map <F2> GoDate: <Esc>:read !date<CR>kJ + +This shows how three modes are used. After going to the last line with "G", +the "o" command opens a new line and starts Insert mode. The text "Date: " is +inserted and <Esc> takes you out of insert mode. + Notice the use of special keys inside <>. This is called angle bracket +notation. You type these as separate characters, not by pressing the key +itself. This makes the mappings better readable and you can copy and paste +the text without problems. + The ":" character takes Vim to the command line. The ":read !date" command +reads the output from the "date" command and appends it below the current +line. The <CR> is required to execute the ":read" command. + At this point of execution the text looks like this: + + Date: ~ + Fri Jun 15 12:54:34 CEST 2001 ~ + +Now "kJ" moves the cursor up and joins the lines together. + To decide which key or keys you use for mapping, see |map-which-keys|. + + +MAPPING AND MODES + +The ":map" command defines remapping for keys in Normal mode. You can also +define mappings for other modes. For example, ":imap" applies to Insert mode. +You can use it to insert a date below the cursor: > + + :imap <F2> <CR>Date: <Esc>:read !date<CR>kJ + +It looks a lot like the mapping for <F2> in Normal mode, only the start is +different. The <F2> mapping for Normal mode is still there. Thus you can map +the same key differently for each mode. + Notice that, although this mapping starts in Insert mode, it ends in Normal +mode. If you want it to continue in Insert mode, append an "a" to the +mapping. + +Here is an overview of map commands and in which mode they work: + + :map Normal, Visual and Operator-pending + :vmap Visual + :nmap Normal + :omap Operator-pending + :map! Insert and Command-line + :imap Insert + :cmap Command-line + +Operator-pending mode is when you typed an operator character, such as "d" or +"y", and you are expected to type the motion command or a text object. Thus +when you type "dw", the "w" is entered in operator-pending mode. + +Suppose that you want to define <F7> so that the command d<F7> deletes a C +program block (text enclosed in curly braces, {}). Similarly y<F7> would yank +the program block into the unnamed register. Therefore, what you need to do +is to define <F7> to select the current program block. You can do this with +the following command: > + + :omap <F7> a{ + +This causes <F7> to perform a select block "a{" in operator-pending mode, just +like you typed it. This mapping is useful if typing a { on your keyboard is a +bit difficult. + + +LISTING MAPPINGS + +To see the currently defined mappings, use ":map" without arguments. Or one +of the variants that include the mode in which they work. The output could +look like this: + + _g :call MyGrep(1)<CR> ~ + v <F2> :s/^/> /<CR>:noh<CR>`` ~ + n <F2> :.,$s/^/> /<CR>:noh<CR>`` ~ + <xHome> <Home> + <xEnd> <End> + + +The first column of the list shows in which mode the mapping is effective. +This is "n" for Normal mode, "i" for Insert mode, etc. A blank is used for a +mapping defined with ":map", thus effective in both Normal and Visual mode. + One useful purpose of listing the mapping is to check if special keys in <> +form have been recognized (this only works when color is supported). For +example, when <Esc> is displayed in color, it stands for the escape character. +When it has the same color as the other text, it is five characters. + + +REMAPPING + +The result of a mapping is inspected for other mappings in it. For example, +the mappings for <F2> above could be shortened to: > + + :map <F2> G<F3> + :imap <F2> <Esc><F3> + :map <F3> oDate: <Esc>:read !date<CR>kJ + +For Normal mode <F2> is mapped to go to the last line, and then behave like +<F3> was pressed. In Insert mode <F2> stops Insert mode with <Esc> and then +also uses <F3>. Then <F3> is mapped to do the actual work. + +Suppose you hardly ever use Ex mode, and want to use the "Q" command to format +text (this was so in old versions of Vim). This mapping will do it: > + + :map Q gq + +But, in rare cases you need to use Ex mode anyway. Let's map "gQ" to Q, so +that you can still go to Ex mode: > + + :map gQ Q + +What happens now is that when you type "gQ" it is mapped to "Q". So far so +good. But then "Q" is mapped to "gq", thus typing "gQ" results in "gq", and +you don't get to Ex mode at all. + To avoid keys to be mapped again, use the ":noremap" command: > + + :noremap gQ Q + +Now Vim knows that the "Q" is not to be inspected for mappings that apply to +it. There is a similar command for every mode: + + :noremap Normal, Visual and Operator-pending + :vnoremap Visual + :nnoremap Normal + :onoremap Operator-pending + :noremap! Insert and Command-line + :inoremap Insert + :cnoremap Command-line + + +RECURSIVE MAPPING + +When a mapping triggers itself, it will run forever. This can be used to +repeat an action an unlimited number of times. + For example, you have a list of files that contain a version number in the +first line. You edit these files with "vim *.txt". You are now editing the +first file. Define this mapping: > + + :map ,, :s/5.1/5.2/<CR>:wnext<CR>,, + +Now you type ",,". This triggers the mapping. It replaces "5.1" with "5.2" +in the first line. Then it does a ":wnext" to write the file and edit the +next one. The mapping ends in ",,". This triggers the same mapping again, +thus doing the substitution, etc. + This continues until there is an error. In this case it could be a file +where the substitute command doesn't find a match for "5.1". You can then +make a change to insert "5.1" and continue by typing ",," again. Or the +":wnext" fails, because you are in the last file in the list. + When a mapping runs into an error halfway, the rest of the mapping is +discarded. CTRL-C interrupts the mapping (CTRL-Break on MS-Windows). + + +DELETE A MAPPING + +To remove a mapping use the ":unmap" command. Again, the mode the unmapping +applies to depends on the command used: + + :unmap Normal, Visual and Operator-pending + :vunmap Visual + :nunmap Normal + :ounmap Operator-pending + :unmap! Insert and Command-line + :iunmap Insert + :cunmap Command-line + +There is a trick to define a mapping that works in Normal and Operator-pending +mode, but not in Visual mode. First define it for all three modes, then +delete it for Visual mode: > + + :map <C-A> /---><CR> + :vunmap <C-A> + +Notice that the five characters "<C-A>" stand for the single key CTRL-A. + +To remove all mappings use the |:mapclear| command. You can guess the +variations for different modes by now. Be careful with this command, it can't +be undone. + + +SPECIAL CHARACTERS + +The ":map" command can be followed by another command. A | character +separates the two commands. This also means that a | character can't be used +inside a map command. To include one, use <Bar> (five characters). Example: +> + :map <F8> :write <Bar> !checkin %:S<CR> + +The same problem applies to the ":unmap" command, with the addition that you +have to watch out for trailing white space. These two commands are different: +> + :unmap a | unmap b + :unmap a| unmap b + +The first command tries to unmap "a ", with a trailing space. + +When using a space inside a mapping, use <Space> (seven characters): > + + :map <Space> W + +This makes the spacebar move a blank-separated word forward. + +It is not possible to put a comment directly after a mapping, because the " +character is considered to be part of the mapping. You can use |", this +starts a new, empty command with a comment. Example: > + + :map <Space> W| " Use spacebar to move forward a word + + +MAPPINGS AND ABBREVIATIONS + +Abbreviations are a lot like Insert mode mappings. The arguments are handled +in the same way. The main difference is the way they are triggered. An +abbreviation is triggered by typing a non-word character after the word. A +mapping is triggered when typing the last character. + Another difference is that the characters you type for an abbreviation are +inserted in the text while you type them. When the abbreviation is triggered +these characters are deleted and replaced by what the abbreviation produces. +When typing the characters for a mapping, nothing is inserted until you type +the last character that triggers it. If the 'showcmd' option is set, the +typed characters are displayed in the last line of the Vim window. + An exception is when a mapping is ambiguous. Suppose you have done two +mappings: > + + :imap aa foo + :imap aaa bar + +Now, when you type "aa", Vim doesn't know if it should apply the first or the +second mapping. It waits for another character to be typed. If it is an "a", +the second mapping is applied and results in "bar". If it is a space, for +example, the first mapping is applied, resulting in "foo", and then the space +is inserted. + + +ADDITIONALLY... + +The <script> keyword can be used to make a mapping local to a script. See +|:map-<script>|. + +The <buffer> keyword can be used to make a mapping local to a specific buffer. +See |:map-<buffer>| + +The <unique> keyword can be used to make defining a new mapping fail when it +already exists. Otherwise a new mapping simply overwrites the old one. See +|:map-<unique>|. + +To make a key do nothing, map it to <Nop> (five characters). This will make +the <F7> key do nothing at all: > + + :map <F7> <Nop>| map! <F7> <Nop> + +There must be no space after <Nop>. + +============================================================================== +*40.2* Defining command-line commands + +The Vim editor enables you to define your own commands. You execute these +commands just like any other Command-line mode command. + To define a command, use the ":command" command, as follows: > + + :command DeleteFirst 1delete + +Now when you execute the command ":DeleteFirst" Vim executes ":1delete", which +deletes the first line. + + Note: + User-defined commands must start with a capital letter. You cannot + use ":X", ":Next" and ":Print". The underscore cannot be used! You + can use digits, but this is discouraged. + +To list the user-defined commands, execute the following command: > + + :command + +Just like with the builtin commands, the user defined commands can be +abbreviated. You need to type just enough to distinguish the command from +another. Command line completion can be used to get the full name. + + +NUMBER OF ARGUMENTS + +User-defined commands can take a series of arguments. The number of arguments +must be specified by the -nargs option. For instance, the example +:DeleteFirst command takes no arguments, so you could have defined it as +follows: > + + :command -nargs=0 DeleteFirst 1delete + +However, because zero arguments is the default, you do not need to add +"-nargs=0". The other values of -nargs are as follows: + + -nargs=0 No arguments + -nargs=1 One argument + -nargs=* Any number of arguments + -nargs=? Zero or one argument + -nargs=+ One or more arguments + + +USING THE ARGUMENTS + +Inside the command definition, the arguments are represented by the +<args> keyword. For example: > + + :command -nargs=+ Say :echo "<args>" + +Now when you type > + + :Say Hello World + +Vim echoes "Hello World". However, if you add a double quote, it won't work. +For example: > + + :Say he said "hello" + +To get special characters turned into a string, properly escaped to use as an +expression, use "<q-args>": > + + :command -nargs=+ Say :echo <q-args> + +Now the above ":Say" command will result in this to be executed: > + + :echo "he said \"hello\"" + +The <f-args> keyword contains the same information as the <args> keyword, +except in a format suitable for use as function call arguments. For example: +> + :command -nargs=* DoIt :call AFunction(<f-args>) + :DoIt a b c + +Executes the following command: > + + :call AFunction("a", "b", "c") + + +LINE RANGE + +Some commands take a range as their argument. To tell Vim that you are +defining such a command, you need to specify a -range option. The values for +this option are as follows: + + -range Range is allowed; default is the current line. + -range=% Range is allowed; default is the whole file. + -range={count} Range is allowed; the last number in it is used as a + single number whose default is {count}. + +When a range is specified, the keywords <line1> and <line2> get the values of +the first and last line in the range. For example, the following command +defines the SaveIt command, which writes out the specified range to the file +"save_file": > + + :command -range=% SaveIt :<line1>,<line2>write! save_file + + +OTHER OPTIONS + +Some of the other options and keywords are as follows: + + -count={number} The command can take a count whose default is + {number}. The resulting count can be used + through the <count> keyword. + -bang You can use a !. If present, using <bang> will + result in a !. + -register You can specify a register. (The default is + the unnamed register.) + The register specification is available as + <reg> (a.k.a. <register>). + -complete={type} Type of command-line completion used. See + |:command-completion| for the list of possible + values. + -bar The command can be followed by | and another + command, or " and a comment. + -buffer The command is only available for the current + buffer. + +Finally, you have the <lt> keyword. It stands for the character <. Use this +to escape the special meaning of the <> items mentioned. + + +REDEFINING AND DELETING + +To redefine the same command use the ! argument: > + + :command -nargs=+ Say :echo "<args>" + :command! -nargs=+ Say :echo <q-args> + +To delete a user command use ":delcommand". It takes a single argument, which +is the name of the command. Example: > + + :delcommand SaveIt + +To delete all the user commands: > + + :comclear + +Careful, this can't be undone! + +More details about all this in the reference manual: |user-commands|. + +============================================================================== +*40.3* Autocommands + +An autocommand is a command that is executed automatically in response to some +event, such as a file being read or written or a buffer change. Through the +use of autocommands you can train Vim to edit compressed files, for example. +That is used in the |gzip| plugin. + Autocommands are very powerful. Use them with care and they will help you +avoid typing many commands. Use them carelessly and they will cause a lot of +trouble. + +Suppose you want to replace a datestamp on the end of a file every time it is +written. First you define a function: > + + :function DateInsert() + : $delete + : read !date + :endfunction + +You want this function to be called each time, just before a buffer is written +to a file. This will make that happen: > + + :autocmd BufWritePre * call DateInsert() + +"BufWritePre" is the event for which this autocommand is triggered: Just +before (pre) writing a buffer to a file. The "*" is a pattern to match with +the file name. In this case it matches all files. + With this command enabled, when you do a ":write", Vim checks for any +matching BufWritePre autocommands and executes them, and then it +performs the ":write". + The general form of the :autocmd command is as follows: > + + :autocmd [group] {events} {file-pattern} [++nested] {command} + +The [group] name is optional. It is used in managing and calling the commands +(more on this later). The {events} parameter is a list of events (comma +separated) that trigger the command. + {file-pattern} is a filename, usually with wildcards. For example, using +"*.txt" makes the autocommand be used for all files whose name end in ".txt". +The optional [++nested] flag allows for nesting of autocommands (see below), +and finally, {command} is the command to be executed. + + +EVENTS + +One of the most useful events is BufReadPost. It is triggered after a new +file is being edited. It is commonly used to set option values. For example, +you know that "*.gsm" files are GNU assembly language. To get the syntax file +right, define this autocommand: > + + :autocmd BufReadPost *.gsm set filetype=asm + +If Vim is able to detect the type of file, it will set the 'filetype' option +for you. This triggers the Filetype event. Use this to do something when a +certain type of file is edited. For example, to load a list of abbreviations +for text files: > + + :autocmd Filetype text source ~/.vim/abbrevs.vim + +When starting to edit a new file, you could make Vim insert a skeleton: > + + :autocmd BufNewFile *.[ch] 0read ~/skeletons/skel.c + +See |autocmd-events| for a complete list of events. + + +PATTERNS + +The {file-pattern} argument can actually be a comma-separated list of file +patterns. For example: "*.c,*.h" matches files ending in ".c" and ".h". + The usual file wildcards can be used. Here is a summary of the most often +used ones: + + * Match any character any number of times + ? Match any character once + [abc] Match the character a, b or c + . Matches a dot + a{b,c} Matches "ab" and "ac" + +When the pattern includes a slash (/) Vim will compare directory names. +Without the slash only the last part of a file name is used. For example, +"*.txt" matches "/home/biep/readme.txt". The pattern "/home/biep/*" would +also match it. But "home/foo/*.txt" wouldn't. + When including a slash, Vim matches the pattern against both the full path +of the file ("/home/biep/readme.txt") and the relative path (e.g., +"biep/readme.txt"). + + Note: + When working on a system that uses a backslash as file separator, such + as MS-Windows, you still use forward slashes in autocommands. This + makes it easier to write the pattern, since a backslash has a special + meaning. It also makes the autocommands portable. + + +DELETING + +To delete an autocommand, use the same command as what it was defined with, +but leave out the {command} at the end and use a !. Example: > + + :autocmd! FileWritePre * + +This will delete all autocommands for the "FileWritePre" event that use the +"*" pattern. + + +LISTING + +To list all the currently defined autocommands, use this: > + + :autocmd + +The list can be very long, especially when filetype detection is used. To +list only part of the commands, specify the group, event and/or pattern. For +example, to list all BufNewFile autocommands: > + + :autocmd BufNewFile + +To list all autocommands for the pattern "*.c": > + + :autocmd * *.c + +Using "*" for the event will list all the events. To list all autocommands +for the cprograms group: > + + :autocmd cprograms + + +GROUPS + +The {group} item, used when defining an autocommand, groups related autocommands +together. This can be used to delete all the autocommands in a certain group, +for example. + When defining several autocommands for a certain group, use the ":augroup" +command. For example, let's define autocommands for C programs: > + + :augroup cprograms + : autocmd BufReadPost *.c,*.h :set sw=4 sts=4 + : autocmd BufReadPost *.cpp :set sw=3 sts=3 + :augroup END + +This will do the same as: > + + :autocmd cprograms BufReadPost *.c,*.h :set sw=4 sts=4 + :autocmd cprograms BufReadPost *.cpp :set sw=3 sts=3 + +To delete all autocommands in the "cprograms" group: > + + :autocmd! cprograms + + +NESTING + +Generally, commands executed as the result of an autocommand event will not +trigger any new events. If you read a file in response to a FileChangedShell +event, it will not trigger the autocommands that would set the syntax, for +example. To make the events triggered, add the "nested" argument: > + + :autocmd FileChangedShell * ++nested edit + + +EXECUTING AUTOCOMMANDS + +It is possible to trigger an autocommand by pretending an event has occurred. +This is useful to have one autocommand trigger another one. Example: > + + :autocmd BufReadPost *.new execute "doautocmd BufReadPost " . expand("<afile>:r") + +This defines an autocommand that is triggered when a new file has been edited. +The file name must end in ".new". The ":execute" command uses expression +evaluation to form a new command and execute it. When editing the file +"tryout.c.new" the executed command will be: > + + :doautocmd BufReadPost tryout.c + +The expand() function takes the "<afile>" argument, which stands for the file +name the autocommand was executed for, and takes the root of the file name +with ":r". + +":doautocmd" executes on the current buffer. The ":doautoall" command works +like "doautocmd" except it executes on all the buffers. + + +USING NORMAL MODE COMMANDS + +The commands executed by an autocommand are Command-line commands. If you +want to use a Normal mode command, the ":normal" command can be used. +Example: > + + :autocmd BufReadPost *.log normal G + +This will make the cursor jump to the last line of *.log files when you start +to edit it. + Using the ":normal" command is a bit tricky. First of all, make sure its +argument is a complete command, including all the arguments. When you use "i" +to go to Insert mode, there must also be a <Esc> to leave Insert mode again. +If you use a "/" to start a search pattern, there must be a <CR> to execute +it. + The ":normal" command uses all the text after it as commands. Thus there +can be no | and another command following. To work around this, put the +":normal" command inside an ":execute" command. This also makes it possible +to pass unprintable characters in a convenient way. Example: > + + :autocmd BufReadPost *.chg execute "normal ONew entry:\<Esc>" | + \ 1read !date + +This also shows the use of a backslash to break a long command into more +lines. This can be used in Vim scripts (not at the command line). + +When you want the autocommand do something complicated, which involves jumping +around in the file and then returning to the original position, you may want +to restore the view on the file. See |restore-position| for an example. + + +IGNORING EVENTS + +At times, you will not want to trigger an autocommand. The 'eventignore' +option contains a list of events that will be totally ignored. For example, +the following causes events for entering and leaving a window to be ignored: > + + :set eventignore=WinEnter,WinLeave + +To ignore all events, use the following command: > + + :set eventignore=all + +To set it back to the normal behavior, make 'eventignore' empty: > + + :set eventignore= + +============================================================================== + +Next chapter: |usr_41.txt| Write a Vim script + +Copyright: see |manual-copyright| vim:tw=78:ts=8:noet:ft=help:norl: |