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diff --git a/vim73/doc/usr_41.txt b/vim73/doc/usr_41.txt new file mode 100644 index 0000000..fc0782f --- /dev/null +++ b/vim73/doc/usr_41.txt @@ -0,0 +1,2431 @@ +*usr_41.txt* For Vim version 7.3. Last change: 2010 Nov 17 + + VIM USER MANUAL - by Bram Moolenaar + + Write a Vim script + + +The Vim script language is used for the startup vimrc file, syntax files, and +many other things. This chapter explains the items that can be used in a Vim +script. There are a lot of them, thus this is a long chapter. + +|41.1| Introduction +|41.2| Variables +|41.3| Expressions +|41.4| Conditionals +|41.5| Executing an expression +|41.6| Using functions +|41.7| Defining a function +|41.8| Lists and Dictionaries +|41.9| Exceptions +|41.10| Various remarks +|41.11| Writing a plugin +|41.12| Writing a filetype plugin +|41.13| Writing a compiler plugin +|41.14| Writing a plugin that loads quickly +|41.15| Writing library scripts +|41.16| Distributing Vim scripts + + Next chapter: |usr_42.txt| Add new menus + Previous chapter: |usr_40.txt| Make new commands +Table of contents: |usr_toc.txt| + +============================================================================== +*41.1* Introduction *vim-script-intro* *script* + +Your first experience with Vim scripts is the vimrc file. Vim reads it when +it starts up and executes the commands. You can set options to values you +prefer. And you can use any colon command in it (commands that start with a +":"; these are sometimes referred to as Ex commands or command-line commands). + Syntax files are also Vim scripts. As are files that set options for a +specific file type. A complicated macro can be defined by a separate Vim +script file. You can think of other uses yourself. + +Let's start with a simple example: > + + :let i = 1 + :while i < 5 + : echo "count is" i + : let i += 1 + :endwhile +< + Note: + The ":" characters are not really needed here. You only need to use + them when you type a command. In a Vim script file they can be left + out. We will use them here anyway to make clear these are colon + commands and make them stand out from Normal mode commands. + Note: + You can try out the examples by yanking the lines from the text here + and executing them with :@" + +The output of the example code is: + + count is 1 ~ + count is 2 ~ + count is 3 ~ + count is 4 ~ + +In the first line the ":let" command assigns a value to a variable. The +generic form is: > + + :let {variable} = {expression} + +In this case the variable name is "i" and the expression is a simple value, +the number one. + The ":while" command starts a loop. The generic form is: > + + :while {condition} + : {statements} + :endwhile + +The statements until the matching ":endwhile" are executed for as long as the +condition is true. The condition used here is the expression "i < 5". This +is true when the variable i is smaller than five. + Note: + If you happen to write a while loop that keeps on running, you can + interrupt it by pressing CTRL-C (CTRL-Break on MS-Windows). + +The ":echo" command prints its arguments. In this case the string "count is" +and the value of the variable i. Since i is one, this will print: + + count is 1 ~ + +Then there is the ":let i += 1" command. This does the same thing as +":let i = i + 1". This adds one to the variable i and assigns the new value +to the same variable. + +The example was given to explain the commands, but would you really want to +make such a loop it can be written much more compact: > + + :for i in range(1, 4) + : echo "count is" i + :endfor + +We won't explain how |:for| and |range()| work until later. Follow the links +if you are impatient. + + +THREE KINDS OF NUMBERS + +Numbers can be decimal, hexadecimal or octal. A hexadecimal number starts +with "0x" or "0X". For example "0x1f" is decimal 31. An octal number starts +with a zero. "017" is decimal 15. Careful: don't put a zero before a decimal +number, it will be interpreted as an octal number! + The ":echo" command always prints decimal numbers. Example: > + + :echo 0x7f 036 +< 127 30 ~ + +A number is made negative with a minus sign. This also works for hexadecimal +and octal numbers. A minus sign is also used for subtraction. Compare this +with the previous example: > + + :echo 0x7f -036 +< 97 ~ + +White space in an expression is ignored. However, it's recommended to use it +for separating items, to make the expression easier to read. For example, to +avoid the confusion with a negative number above, put a space between the +minus sign and the following number: > + + :echo 0x7f - 036 + +============================================================================== +*41.2* Variables + +A variable name consists of ASCII letters, digits and the underscore. It +cannot start with a digit. Valid variable names are: + + counter + _aap3 + very_long_variable_name_with_underscores + FuncLength + LENGTH + +Invalid names are "foo+bar" and "6var". + These variables are global. To see a list of currently defined variables +use this command: > + + :let + +You can use global variables everywhere. This also means that when the +variable "count" is used in one script file, it might also be used in another +file. This leads to confusion at least, and real problems at worst. To avoid +this, you can use a variable local to a script file by prepending "s:". For +example, one script contains this code: > + + :let s:count = 1 + :while s:count < 5 + : source other.vim + : let s:count += 1 + :endwhile + +Since "s:count" is local to this script, you can be sure that sourcing the +"other.vim" script will not change this variable. If "other.vim" also uses an +"s:count" variable, it will be a different copy, local to that script. More +about script-local variables here: |script-variable|. + +There are more kinds of variables, see |internal-variables|. The most often +used ones are: + + b:name variable local to a buffer + w:name variable local to a window + g:name global variable (also in a function) + v:name variable predefined by Vim + + +DELETING VARIABLES + +Variables take up memory and show up in the output of the ":let" command. To +delete a variable use the ":unlet" command. Example: > + + :unlet s:count + +This deletes the script-local variable "s:count" to free up the memory it +uses. If you are not sure if the variable exists, and don't want an error +message when it doesn't, append !: > + + :unlet! s:count + +When a script finishes, the local variables used there will not be +automatically freed. The next time the script executes, it can still use the +old value. Example: > + + :if !exists("s:call_count") + : let s:call_count = 0 + :endif + :let s:call_count = s:call_count + 1 + :echo "called" s:call_count "times" + +The "exists()" function checks if a variable has already been defined. Its +argument is the name of the variable you want to check. Not the variable +itself! If you would do this: > + + :if !exists(s:call_count) + +Then the value of s:call_count will be used as the name of the variable that +exists() checks. That's not what you want. + The exclamation mark ! negates a value. When the value was true, it +becomes false. When it was false, it becomes true. You can read it as "not". +Thus "if !exists()" can be read as "if not exists()". + What Vim calls true is anything that is not zero. Zero is false. + Note: + Vim automatically converts a string to a number when it is looking for + a number. When using a string that doesn't start with a digit the + resulting number is zero. Thus look out for this: > + :if "true" +< The "true" will be interpreted as a zero, thus as false! + + +STRING VARIABLES AND CONSTANTS + +So far only numbers were used for the variable value. Strings can be used as +well. Numbers and strings are the basic types of variables that Vim supports. +The type is dynamic, it is set each time when assigning a value to the +variable with ":let". More about types in |41.8|. + To assign a string value to a variable, you need to use a string constant. +There are two types of these. First the string in double quotes: > + + :let name = "peter" + :echo name +< peter ~ + +If you want to include a double quote inside the string, put a backslash in +front of it: > + + :let name = "\"peter\"" + :echo name +< "peter" ~ + +To avoid the need for a backslash, you can use a string in single quotes: > + + :let name = '"peter"' + :echo name +< "peter" ~ + +Inside a single-quote string all the characters are as they are. Only the +single quote itself is special: you need to use two to get one. A backslash +is taken literally, thus you can't use it to change the meaning of the +character after it. + In double-quote strings it is possible to use special characters. Here are +a few useful ones: + + \t <Tab> + \n <NL>, line break + \r <CR>, <Enter> + \e <Esc> + \b <BS>, backspace + \" " + \\ \, backslash + \<Esc> <Esc> + \<C-W> CTRL-W + +The last two are just examples. The "\<name>" form can be used to include +the special key "name". + See |expr-quote| for the full list of special items in a string. + +============================================================================== +*41.3* Expressions + +Vim has a rich, yet simple way to handle expressions. You can read the +definition here: |expression-syntax|. Here we will show the most common +items. + The numbers, strings and variables mentioned above are expressions by +themselves. Thus everywhere an expression is expected, you can use a number, +string or variable. Other basic items in an expression are: + + $NAME environment variable + &name option + @r register + +Examples: > + + :echo "The value of 'tabstop' is" &ts + :echo "Your home directory is" $HOME + :if @a > 5 + +The &name form can be used to save an option value, set it to a new value, +do something and restore the old value. Example: > + + :let save_ic = &ic + :set noic + :/The Start/,$delete + :let &ic = save_ic + +This makes sure the "The Start" pattern is used with the 'ignorecase' option +off. Still, it keeps the value that the user had set. (Another way to do +this would be to add "\C" to the pattern, see |/\C|.) + + +MATHEMATICS + +It becomes more interesting if we combine these basic items. Let's start with +mathematics on numbers: + + a + b add + a - b subtract + a * b multiply + a / b divide + a % b modulo + +The usual precedence is used. Example: > + + :echo 10 + 5 * 2 +< 20 ~ + +Grouping is done with braces. No surprises here. Example: > + + :echo (10 + 5) * 2 +< 30 ~ + +Strings can be concatenated with ".". Example: > + + :echo "foo" . "bar" +< foobar ~ + +When the ":echo" command gets multiple arguments, it separates them with a +space. In the example the argument is a single expression, thus no space is +inserted. + +Borrowed from the C language is the conditional expression: + + a ? b : c + +If "a" evaluates to true "b" is used, otherwise "c" is used. Example: > + + :let i = 4 + :echo i > 5 ? "i is big" : "i is small" +< i is small ~ + +The three parts of the constructs are always evaluated first, thus you could +see it work as: + + (a) ? (b) : (c) + +============================================================================== +*41.4* Conditionals + +The ":if" commands executes the following statements, until the matching +":endif", only when a condition is met. The generic form is: + + :if {condition} + {statements} + :endif + +Only when the expression {condition} evaluates to true (non-zero) will the +{statements} be executed. These must still be valid commands. If they +contain garbage, Vim won't be able to find the ":endif". + You can also use ":else". The generic form for this is: + + :if {condition} + {statements} + :else + {statements} + :endif + +The second {statements} is only executed if the first one isn't. + Finally, there is ":elseif": + + :if {condition} + {statements} + :elseif {condition} + {statements} + :endif + +This works just like using ":else" and then "if", but without the need for an +extra ":endif". + A useful example for your vimrc file is checking the 'term' option and +doing something depending upon its value: > + + :if &term == "xterm" + : " Do stuff for xterm + :elseif &term == "vt100" + : " Do stuff for a vt100 terminal + :else + : " Do something for other terminals + :endif + + +LOGIC OPERATIONS + +We already used some of them in the examples. These are the most often used +ones: + + a == b equal to + a != b not equal to + a > b greater than + a >= b greater than or equal to + a < b less than + a <= b less than or equal to + +The result is one if the condition is met and zero otherwise. An example: > + + :if v:version >= 700 + : echo "congratulations" + :else + : echo "you are using an old version, upgrade!" + :endif + +Here "v:version" is a variable defined by Vim, which has the value of the Vim +version. 600 is for version 6.0. Version 6.1 has the value 601. This is +very useful to write a script that works with multiple versions of Vim. +|v:version| + +The logic operators work both for numbers and strings. When comparing two +strings, the mathematical difference is used. This compares byte values, +which may not be right for some languages. + When comparing a string with a number, the string is first converted to a +number. This is a bit tricky, because when a string doesn't look like a +number, the number zero is used. Example: > + + :if 0 == "one" + : echo "yes" + :endif + +This will echo "yes", because "one" doesn't look like a number, thus it is +converted to the number zero. + +For strings there are two more items: + + a =~ b matches with + a !~ b does not match with + +The left item "a" is used as a string. The right item "b" is used as a +pattern, like what's used for searching. Example: > + + :if str =~ " " + : echo "str contains a space" + :endif + :if str !~ '\.$' + : echo "str does not end in a full stop" + :endif + +Notice the use of a single-quote string for the pattern. This is useful, +because backslashes would need to be doubled in a double-quote string and +patterns tend to contain many backslashes. + +The 'ignorecase' option is used when comparing strings. When you don't want +that, append "#" to match case and "?" to ignore case. Thus "==?" compares +two strings to be equal while ignoring case. And "!~#" checks if a pattern +doesn't match, also checking the case of letters. For the full table see +|expr-==|. + + +MORE LOOPING + +The ":while" command was already mentioned. Two more statements can be used +in between the ":while" and the ":endwhile": + + :continue Jump back to the start of the while loop; the + loop continues. + :break Jump forward to the ":endwhile"; the loop is + discontinued. + +Example: > + + :while counter < 40 + : call do_something() + : if skip_flag + : continue + : endif + : if finished_flag + : break + : endif + : sleep 50m + :endwhile + +The ":sleep" command makes Vim take a nap. The "50m" specifies fifty +milliseconds. Another example is ":sleep 4", which sleeps for four seconds. + +Even more looping can be done with the ":for" command, see below in |41.8|. + +============================================================================== +*41.5* Executing an expression + +So far the commands in the script were executed by Vim directly. The +":execute" command allows executing the result of an expression. This is a +very powerful way to build commands and execute them. + An example is to jump to a tag, which is contained in a variable: > + + :execute "tag " . tag_name + +The "." is used to concatenate the string "tag " with the value of variable +"tag_name". Suppose "tag_name" has the value "get_cmd", then the command that +will be executed is: > + + :tag get_cmd + +The ":execute" command can only execute colon commands. The ":normal" command +executes Normal mode commands. However, its argument is not an expression but +the literal command characters. Example: > + + :normal gg=G + +This jumps to the first line and formats all lines with the "=" operator. + To make ":normal" work with an expression, combine ":execute" with it. +Example: > + + :execute "normal " . normal_commands + +The variable "normal_commands" must contain the Normal mode commands. + Make sure that the argument for ":normal" is a complete command. Otherwise +Vim will run into the end of the argument and abort the command. For example, +if you start Insert mode, you must leave Insert mode as well. This works: > + + :execute "normal Inew text \<Esc>" + +This inserts "new text " in the current line. Notice the use of the special +key "\<Esc>". This avoids having to enter a real <Esc> character in your +script. + +If you don't want to execute a string but evaluate it to get its expression +value, you can use the eval() function: > + + :let optname = "path" + :let optval = eval('&' . optname) + +A "&" character is prepended to "path", thus the argument to eval() is +"&path". The result will then be the value of the 'path' option. + The same thing can be done with: > + :exe 'let optval = &' . optname + +============================================================================== +*41.6* Using functions + +Vim defines many functions and provides a large amount of functionality that +way. A few examples will be given in this section. You can find the whole +list here: |functions|. + +A function is called with the ":call" command. The parameters are passed in +between braces, separated by commas. Example: > + + :call search("Date: ", "W") + +This calls the search() function, with arguments "Date: " and "W". The +search() function uses its first argument as a search pattern and the second +one as flags. The "W" flag means the search doesn't wrap around the end of +the file. + +A function can be called in an expression. Example: > + + :let line = getline(".") + :let repl = substitute(line, '\a', "*", "g") + :call setline(".", repl) + +The getline() function obtains a line from the current buffer. Its argument +is a specification of the line number. In this case "." is used, which means +the line where the cursor is. + The substitute() function does something similar to the ":substitute" +command. The first argument is the string on which to perform the +substitution. The second argument is the pattern, the third the replacement +string. Finally, the last arguments are the flags. + The setline() function sets the line, specified by the first argument, to a +new string, the second argument. In this example the line under the cursor is +replaced with the result of the substitute(). Thus the effect of the three +statements is equal to: > + + :substitute/\a/*/g + +Using the functions becomes more interesting when you do more work before and +after the substitute() call. + + +FUNCTIONS *function-list* + +There are many functions. We will mention them here, grouped by what they are +used for. You can find an alphabetical list here: |functions|. Use CTRL-] on +the function name to jump to detailed help on it. + +String manipulation: *string-functions* + nr2char() get a character by its ASCII value + char2nr() get ASCII value of a character + str2nr() convert a string to a Number + str2float() convert a string to a Float + printf() format a string according to % items + escape() escape characters in a string with a '\' + shellescape() escape a string for use with a shell command + fnameescape() escape a file name for use with a Vim command + tr() translate characters from one set to another + strtrans() translate a string to make it printable + tolower() turn a string to lowercase + toupper() turn a string to uppercase + match() position where a pattern matches in a string + matchend() position where a pattern match ends in a string + matchstr() match of a pattern in a string + matchlist() like matchstr() and also return submatches + stridx() first index of a short string in a long string + strridx() last index of a short string in a long string + strlen() length of a string + substitute() substitute a pattern match with a string + submatch() get a specific match in a ":substitute" + strpart() get part of a string + expand() expand special keywords + iconv() convert text from one encoding to another + byteidx() byte index of a character in a string + repeat() repeat a string multiple times + eval() evaluate a string expression + +List manipulation: *list-functions* + get() get an item without error for wrong index + len() number of items in a List + empty() check if List is empty + insert() insert an item somewhere in a List + add() append an item to a List + extend() append a List to a List + remove() remove one or more items from a List + copy() make a shallow copy of a List + deepcopy() make a full copy of a List + filter() remove selected items from a List + map() change each List item + sort() sort a List + reverse() reverse the order of a List + split() split a String into a List + join() join List items into a String + range() return a List with a sequence of numbers + string() String representation of a List + call() call a function with List as arguments + index() index of a value in a List + max() maximum value in a List + min() minimum value in a List + count() count number of times a value appears in a List + repeat() repeat a List multiple times + +Dictionary manipulation: *dict-functions* + get() get an entry without an error for a wrong key + len() number of entries in a Dictionary + has_key() check whether a key appears in a Dictionary + empty() check if Dictionary is empty + remove() remove an entry from a Dictionary + extend() add entries from one Dictionary to another + filter() remove selected entries from a Dictionary + map() change each Dictionary entry + keys() get List of Dictionary keys + values() get List of Dictionary values + items() get List of Dictionary key-value pairs + copy() make a shallow copy of a Dictionary + deepcopy() make a full copy of a Dictionary + string() String representation of a Dictionary + max() maximum value in a Dictionary + min() minimum value in a Dictionary + count() count number of times a value appears + +Floating point computation: *float-functions* + float2nr() convert Float to Number + abs() absolute value (also works for Number) + round() round off + ceil() round up + floor() round down + trunc() remove value after decimal point + log10() logarithm to base 10 + pow() value of x to the exponent y + sqrt() square root + sin() sine + cos() cosine + atan() arc tangent + +Variables: *var-functions* + type() type of a variable + islocked() check if a variable is locked + function() get a Funcref for a function name + getbufvar() get a variable value from a specific buffer + setbufvar() set a variable in a specific buffer + getwinvar() get a variable from specific window + gettabvar() get a variable from specific tab page + gettabwinvar() get a variable from specific window & tab page + setwinvar() set a variable in a specific window + settabvar() set a variable in a specific tab page + settabwinvar() set a variable in a specific window & tab page + garbagecollect() possibly free memory + +Cursor and mark position: *cursor-functions* *mark-functions* + col() column number of the cursor or a mark + virtcol() screen column of the cursor or a mark + line() line number of the cursor or mark + wincol() window column number of the cursor + winline() window line number of the cursor + cursor() position the cursor at a line/column + getpos() get position of cursor, mark, etc. + setpos() set position of cursor, mark, etc. + byte2line() get line number at a specific byte count + line2byte() byte count at a specific line + diff_filler() get the number of filler lines above a line + +Working with text in the current buffer: *text-functions* + getline() get a line or list of lines from the buffer + setline() replace a line in the buffer + append() append line or list of lines in the buffer + indent() indent of a specific line + cindent() indent according to C indenting + lispindent() indent according to Lisp indenting + nextnonblank() find next non-blank line + prevnonblank() find previous non-blank line + search() find a match for a pattern + searchpos() find a match for a pattern + searchpair() find the other end of a start/skip/end + searchpairpos() find the other end of a start/skip/end + searchdecl() search for the declaration of a name + + *system-functions* *file-functions* +System functions and manipulation of files: + glob() expand wildcards + globpath() expand wildcards in a number of directories + findfile() find a file in a list of directories + finddir() find a directory in a list of directories + resolve() find out where a shortcut points to + fnamemodify() modify a file name + pathshorten() shorten directory names in a path + simplify() simplify a path without changing its meaning + executable() check if an executable program exists + filereadable() check if a file can be read + filewritable() check if a file can be written to + getfperm() get the permissions of a file + getftype() get the kind of a file + isdirectory() check if a directory exists + getfsize() get the size of a file + getcwd() get the current working directory + haslocaldir() check if current window used |:lcd| + tempname() get the name of a temporary file + mkdir() create a new directory + delete() delete a file + rename() rename a file + system() get the result of a shell command + hostname() name of the system + readfile() read a file into a List of lines + writefile() write a List of lines into a file + +Date and Time: *date-functions* *time-functions* + getftime() get last modification time of a file + localtime() get current time in seconds + strftime() convert time to a string + reltime() get the current or elapsed time accurately + reltimestr() convert reltime() result to a string + + *buffer-functions* *window-functions* *arg-functions* +Buffers, windows and the argument list: + argc() number of entries in the argument list + argidx() current position in the argument list + argv() get one entry from the argument list + bufexists() check if a buffer exists + buflisted() check if a buffer exists and is listed + bufloaded() check if a buffer exists and is loaded + bufname() get the name of a specific buffer + bufnr() get the buffer number of a specific buffer + tabpagebuflist() return List of buffers in a tab page + tabpagenr() get the number of a tab page + tabpagewinnr() like winnr() for a specified tab page + winnr() get the window number for the current window + bufwinnr() get the window number of a specific buffer + winbufnr() get the buffer number of a specific window + getbufline() get a list of lines from the specified buffer + +Command line: *command-line-functions* + getcmdline() get the current command line + getcmdpos() get position of the cursor in the command line + setcmdpos() set position of the cursor in the command line + getcmdtype() return the current command-line type + +Quickfix and location lists: *quickfix-functions* + getqflist() list of quickfix errors + setqflist() modify a quickfix list + getloclist() list of location list items + setloclist() modify a location list + +Insert mode completion: *completion-functions* + complete() set found matches + complete_add() add to found matches + complete_check() check if completion should be aborted + pumvisible() check if the popup menu is displayed + +Folding: *folding-functions* + foldclosed() check for a closed fold at a specific line + foldclosedend() like foldclosed() but return the last line + foldlevel() check for the fold level at a specific line + foldtext() generate the line displayed for a closed fold + foldtextresult() get the text displayed for a closed fold + +Syntax and highlighting: *syntax-functions* *highlighting-functions* + clearmatches() clear all matches defined by |matchadd()| and + the |:match| commands + getmatches() get all matches defined by |matchadd()| and + the |:match| commands + hlexists() check if a highlight group exists + hlID() get ID of a highlight group + synID() get syntax ID at a specific position + synIDattr() get a specific attribute of a syntax ID + synIDtrans() get translated syntax ID + synstack() get list of syntax IDs at a specific position + synconcealed() get info about concealing + diff_hlID() get highlight ID for diff mode at a position + matchadd() define a pattern to highlight (a "match") + matcharg() get info about |:match| arguments + matchdelete() delete a match defined by |matchadd()| or a + |:match| command + setmatches() restore a list of matches saved by + |getmatches()| + +Spelling: *spell-functions* + spellbadword() locate badly spelled word at or after cursor + spellsuggest() return suggested spelling corrections + soundfold() return the sound-a-like equivalent of a word + +History: *history-functions* + histadd() add an item to a history + histdel() delete an item from a history + histget() get an item from a history + histnr() get highest index of a history list + +Interactive: *interactive-functions* + browse() put up a file requester + browsedir() put up a directory requester + confirm() let the user make a choice + getchar() get a character from the user + getcharmod() get modifiers for the last typed character + feedkeys() put characters in the typeahead queue + input() get a line from the user + inputlist() let the user pick an entry from a list + inputsecret() get a line from the user without showing it + inputdialog() get a line from the user in a dialog + inputsave() save and clear typeahead + inputrestore() restore typeahead + +GUI: *gui-functions* + getfontname() get name of current font being used + getwinposx() X position of the GUI Vim window + getwinposy() Y position of the GUI Vim window + +Vim server: *server-functions* + serverlist() return the list of server names + remote_send() send command characters to a Vim server + remote_expr() evaluate an expression in a Vim server + server2client() send a reply to a client of a Vim server + remote_peek() check if there is a reply from a Vim server + remote_read() read a reply from a Vim server + foreground() move the Vim window to the foreground + remote_foreground() move the Vim server window to the foreground + +Window size and position: *window-size-functions* + winheight() get height of a specific window + winwidth() get width of a specific window + winrestcmd() return command to restore window sizes + winsaveview() get view of current window + winrestview() restore saved view of current window + +Various: *various-functions* + mode() get current editing mode + visualmode() last visual mode used + hasmapto() check if a mapping exists + mapcheck() check if a matching mapping exists + maparg() get rhs of a mapping + exists() check if a variable, function, etc. exists + has() check if a feature is supported in Vim + changenr() return number of most recent change + cscope_connection() check if a cscope connection exists + did_filetype() check if a FileType autocommand was used + eventhandler() check if invoked by an event handler + getpid() get process ID of Vim + + libcall() call a function in an external library + libcallnr() idem, returning a number + + getreg() get contents of a register + getregtype() get type of a register + setreg() set contents and type of a register + + taglist() get list of matching tags + tagfiles() get a list of tags files + + mzeval() evaluate |MzScheme| expression + +============================================================================== +*41.7* Defining a function + +Vim enables you to define your own functions. The basic function declaration +begins as follows: > + + :function {name}({var1}, {var2}, ...) + : {body} + :endfunction +< + Note: + Function names must begin with a capital letter. + +Let's define a short function to return the smaller of two numbers. It starts +with this line: > + + :function Min(num1, num2) + +This tells Vim that the function is named "Min" and it takes two arguments: +"num1" and "num2". + The first thing you need to do is to check to see which number is smaller: + > + : if a:num1 < a:num2 + +The special prefix "a:" tells Vim that the variable is a function argument. +Let's assign the variable "smaller" the value of the smallest number: > + + : if a:num1 < a:num2 + : let smaller = a:num1 + : else + : let smaller = a:num2 + : endif + +The variable "smaller" is a local variable. Variables used inside a function +are local unless prefixed by something like "g:", "a:", or "s:". + + Note: + To access a global variable from inside a function you must prepend + "g:" to it. Thus "g:today" inside a function is used for the global + variable "today", and "today" is another variable, local to the + function. + +You now use the ":return" statement to return the smallest number to the user. +Finally, you end the function: > + + : return smaller + :endfunction + +The complete function definition is as follows: > + + :function Min(num1, num2) + : if a:num1 < a:num2 + : let smaller = a:num1 + : else + : let smaller = a:num2 + : endif + : return smaller + :endfunction + +For people who like short functions, this does the same thing: > + + :function Min(num1, num2) + : if a:num1 < a:num2 + : return a:num1 + : endif + : return a:num2 + :endfunction + +A user defined function is called in exactly the same way as a built-in +function. Only the name is different. The Min function can be used like +this: > + + :echo Min(5, 8) + +Only now will the function be executed and the lines be interpreted by Vim. +If there are mistakes, like using an undefined variable or function, you will +now get an error message. When defining the function these errors are not +detected. + +When a function reaches ":endfunction" or ":return" is used without an +argument, the function returns zero. + +To redefine a function that already exists, use the ! for the ":function" +command: > + + :function! Min(num1, num2, num3) + + +USING A RANGE + +The ":call" command can be given a line range. This can have one of two +meanings. When a function has been defined with the "range" keyword, it will +take care of the line range itself. + The function will be passed the variables "a:firstline" and "a:lastline". +These will have the line numbers from the range the function was called with. +Example: > + + :function Count_words() range + : let lnum = a:firstline + : let n = 0 + : while lnum <= a:lastline + : let n = n + len(split(getline(lnum))) + : let lnum = lnum + 1 + : endwhile + : echo "found " . n . " words" + :endfunction + +You can call this function with: > + + :10,30call Count_words() + +It will be executed once and echo the number of words. + The other way to use a line range is by defining a function without the +"range" keyword. The function will be called once for every line in the +range, with the cursor in that line. Example: > + + :function Number() + : echo "line " . line(".") . " contains: " . getline(".") + :endfunction + +If you call this function with: > + + :10,15call Number() + +The function will be called six times. + + +VARIABLE NUMBER OF ARGUMENTS + +Vim enables you to define functions that have a variable number of arguments. +The following command, for instance, defines a function that must have 1 +argument (start) and can have up to 20 additional arguments: > + + :function Show(start, ...) + +The variable "a:1" contains the first optional argument, "a:2" the second, and +so on. The variable "a:0" contains the number of extra arguments. + For example: > + + :function Show(start, ...) + : echohl Title + : echo "Show is " . a:start + : echohl None + : let index = 1 + : while index <= a:0 + : echo " Arg " . index . " is " . a:{index} + : let index = index + 1 + : endwhile + : echo "" + :endfunction + +This uses the ":echohl" command to specify the highlighting used for the +following ":echo" command. ":echohl None" stops it again. The ":echon" +command works like ":echo", but doesn't output a line break. + +You can also use the a:000 variable, it is a List of all the "..." arguments. +See |a:000|. + + +LISTING FUNCTIONS + +The ":function" command lists the names and arguments of all user-defined +functions: > + + :function +< function Show(start, ...) ~ + function GetVimIndent() ~ + function SetSyn(name) ~ + +To see what a function does, use its name as an argument for ":function": > + + :function SetSyn +< 1 if &syntax == '' ~ + 2 let &syntax = a:name ~ + 3 endif ~ + endfunction ~ + + +DEBUGGING + +The line number is useful for when you get an error message or when debugging. +See |debug-scripts| about debugging mode. + You can also set the 'verbose' option to 12 or higher to see all function +calls. Set it to 15 or higher to see every executed line. + + +DELETING A FUNCTION + +To delete the Show() function: > + + :delfunction Show + +You get an error when the function doesn't exist. + + +FUNCTION REFERENCES + +Sometimes it can be useful to have a variable point to one function or +another. You can do it with the function() function. It turns the name of a +function into a reference: > + + :let result = 0 " or 1 + :function! Right() + : return 'Right!' + :endfunc + :function! Wrong() + : return 'Wrong!' + :endfunc + : + :if result == 1 + : let Afunc = function('Right') + :else + : let Afunc = function('Wrong') + :endif + :echo call(Afunc, []) +< Wrong! ~ + +Note that the name of a variable that holds a function reference must start +with a capital. Otherwise it could be confused with the name of a builtin +function. + The way to invoke a function that a variable refers to is with the call() +function. Its first argument is the function reference, the second argument +is a List with arguments. + +Function references are most useful in combination with a Dictionary, as is +explained in the next section. + +============================================================================== +*41.8* Lists and Dictionaries + +So far we have used the basic types String and Number. Vim also supports two +composite types: List and Dictionary. + +A List is an ordered sequence of things. The things can be any kind of value, +thus you can make a List of numbers, a List of Lists and even a List of mixed +items. To create a List with three strings: > + + :let alist = ['aap', 'mies', 'noot'] + +The List items are enclosed in square brackets and separated by commas. To +create an empty List: > + + :let alist = [] + +You can add items to a List with the add() function: > + + :let alist = [] + :call add(alist, 'foo') + :call add(alist, 'bar') + :echo alist +< ['foo', 'bar'] ~ + +List concatenation is done with +: > + + :echo alist + ['foo', 'bar'] +< ['foo', 'bar', 'foo', 'bar'] ~ + +Or, if you want to extend a List directly: > + + :let alist = ['one'] + :call extend(alist, ['two', 'three']) + :echo alist +< ['one', 'two', 'three'] ~ + +Notice that using add() will have a different effect: > + + :let alist = ['one'] + :call add(alist, ['two', 'three']) + :echo alist +< ['one', ['two', 'three']] ~ + +The second argument of add() is added as a single item. + + +FOR LOOP + +One of the nice things you can do with a List is iterate over it: > + + :let alist = ['one', 'two', 'three'] + :for n in alist + : echo n + :endfor +< one ~ + two ~ + three ~ + +This will loop over each element in List "alist", assigning the value to +variable "n". The generic form of a for loop is: > + + :for {varname} in {listexpression} + : {commands} + :endfor + +To loop a certain number of times you need a List of a specific length. The +range() function creates one for you: > + + :for a in range(3) + : echo a + :endfor +< 0 ~ + 1 ~ + 2 ~ + +Notice that the first item of the List that range() produces is zero, thus the +last item is one less than the length of the list. + You can also specify the maximum value, the stride and even go backwards: > + + :for a in range(8, 4, -2) + : echo a + :endfor +< 8 ~ + 6 ~ + 4 ~ + +A more useful example, looping over lines in the buffer: > + + :for line in getline(1, 20) + : if line =~ "Date: " + : echo matchstr(line, 'Date: \zs.*') + : endif + :endfor + +This looks into lines 1 to 20 (inclusive) and echoes any date found in there. + + +DICTIONARIES + +A Dictionary stores key-value pairs. You can quickly lookup a value if you +know the key. A Dictionary is created with curly braces: > + + :let uk2nl = {'one': 'een', 'two': 'twee', 'three': 'drie'} + +Now you can lookup words by putting the key in square brackets: > + + :echo uk2nl['two'] +< twee ~ + +The generic form for defining a Dictionary is: > + + {<key> : <value>, ...} + +An empty Dictionary is one without any keys: > + + {} + +The possibilities with Dictionaries are numerous. There are various functions +for them as well. For example, you can obtain a list of the keys and loop +over them: > + + :for key in keys(uk2nl) + : echo key + :endfor +< three ~ + one ~ + two ~ + +You will notice the keys are not ordered. You can sort the list to get a +specific order: > + + :for key in sort(keys(uk2nl)) + : echo key + :endfor +< one ~ + three ~ + two ~ + +But you can never get back the order in which items are defined. For that you +need to use a List, it stores items in an ordered sequence. + + +DICTIONARY FUNCTIONS + +The items in a Dictionary can normally be obtained with an index in square +brackets: > + + :echo uk2nl['one'] +< een ~ + +A method that does the same, but without so many punctuation characters: > + + :echo uk2nl.one +< een ~ + +This only works for a key that is made of ASCII letters, digits and the +underscore. You can also assign a new value this way: > + + :let uk2nl.four = 'vier' + :echo uk2nl +< {'three': 'drie', 'four': 'vier', 'one': 'een', 'two': 'twee'} ~ + +And now for something special: you can directly define a function and store a +reference to it in the dictionary: > + + :function uk2nl.translate(line) dict + : return join(map(split(a:line), 'get(self, v:val, "???")')) + :endfunction + +Let's first try it out: > + + :echo uk2nl.translate('three two five one') +< drie twee ??? een ~ + +The first special thing you notice is the "dict" at the end of the ":function" +line. This marks the function as being used from a Dictionary. The "self" +local variable will then refer to that Dictionary. + Now let's break up the complicated return command: > + + split(a:line) + +The split() function takes a string, chops it into white separated words +and returns a list with these words. Thus in the example it returns: > + + :echo split('three two five one') +< ['three', 'two', 'five', 'one'] ~ + +This list is the first argument to the map() function. This will go through +the list, evaluating its second argument with "v:val" set to the value of each +item. This is a shortcut to using a for loop. This command: > + + :let alist = map(split(a:line), 'get(self, v:val, "???")') + +Is equivalent to: > + + :let alist = split(a:line) + :for idx in range(len(alist)) + : let alist[idx] = get(self, alist[idx], "???") + :endfor + +The get() function checks if a key is present in a Dictionary. If it is, then +the value is retrieved. If it isn't, then the default value is returned, in +the example it's '???'. This is a convenient way to handle situations where a +key may not be present and you don't want an error message. + +The join() function does the opposite of split(): it joins together a list of +words, putting a space in between. + This combination of split(), map() and join() is a nice way to filter a line +of words in a very compact way. + + +OBJECT ORIENTED PROGRAMMING + +Now that you can put both values and functions in a Dictionary, you can +actually use a Dictionary like an object. + Above we used a Dictionary for translating Dutch to English. We might want +to do the same for other languages. Let's first make an object (aka +Dictionary) that has the translate function, but no words to translate: > + + :let transdict = {} + :function transdict.translate(line) dict + : return join(map(split(a:line), 'get(self.words, v:val, "???")')) + :endfunction + +It's slightly different from the function above, using 'self.words' to lookup +word translations. But we don't have a self.words. Thus you could call this +an abstract class. + +Now we can instantiate a Dutch translation object: > + + :let uk2nl = copy(transdict) + :let uk2nl.words = {'one': 'een', 'two': 'twee', 'three': 'drie'} + :echo uk2nl.translate('three one') +< drie een ~ + +And a German translator: > + + :let uk2de = copy(transdict) + :let uk2de.words = {'one': 'ein', 'two': 'zwei', 'three': 'drei'} + :echo uk2de.translate('three one') +< drei ein ~ + +You see that the copy() function is used to make a copy of the "transdict" +Dictionary and then the copy is changed to add the words. The original +remains the same, of course. + +Now you can go one step further, and use your preferred translator: > + + :if $LANG =~ "de" + : let trans = uk2de + :else + : let trans = uk2nl + :endif + :echo trans.translate('one two three') +< een twee drie ~ + +Here "trans" refers to one of the two objects (Dictionaries). No copy is +made. More about List and Dictionary identity can be found at |list-identity| +and |dict-identity|. + +Now you might use a language that isn't supported. You can overrule the +translate() function to do nothing: > + + :let uk2uk = copy(transdict) + :function! uk2uk.translate(line) + : return a:line + :endfunction + :echo uk2uk.translate('three one wladiwostok') +< three one wladiwostok ~ + +Notice that a ! was used to overwrite the existing function reference. Now +use "uk2uk" when no recognized language is found: > + + :if $LANG =~ "de" + : let trans = uk2de + :elseif $LANG =~ "nl" + : let trans = uk2nl + :else + : let trans = uk2uk + :endif + :echo trans.translate('one two three') +< one two three ~ + +For further reading see |Lists| and |Dictionaries|. + +============================================================================== +*41.9* Exceptions + +Let's start with an example: > + + :try + : read ~/templates/pascal.tmpl + :catch /E484:/ + : echo "Sorry, the Pascal template file cannot be found." + :endtry + +The ":read" command will fail if the file does not exist. Instead of +generating an error message, this code catches the error and gives the user a +nice message instead. + +For the commands in between ":try" and ":endtry" errors are turned into +exceptions. An exception is a string. In the case of an error the string +contains the error message. And every error message has a number. In this +case, the error we catch contains "E484:". This number is guaranteed to stay +the same (the text may change, e.g., it may be translated). + +When the ":read" command causes another error, the pattern "E484:" will not +match in it. Thus this exception will not be caught and result in the usual +error message. + +You might be tempted to do this: > + + :try + : read ~/templates/pascal.tmpl + :catch + : echo "Sorry, the Pascal template file cannot be found." + :endtry + +This means all errors are caught. But then you will not see errors that are +useful, such as "E21: Cannot make changes, 'modifiable' is off". + +Another useful mechanism is the ":finally" command: > + + :let tmp = tempname() + :try + : exe ".,$write " . tmp + : exe "!filter " . tmp + : .,$delete + : exe "$read " . tmp + :finally + : call delete(tmp) + :endtry + +This filters the lines from the cursor until the end of the file through the +"filter" command, which takes a file name argument. No matter if the +filtering works, something goes wrong in between ":try" and ":finally" or the +user cancels the filtering by pressing CTRL-C, the "call delete(tmp)" is +always executed. This makes sure you don't leave the temporary file behind. + +More information about exception handling can be found in the reference +manual: |exception-handling|. + +============================================================================== +*41.10* Various remarks + +Here is a summary of items that apply to Vim scripts. They are also mentioned +elsewhere, but form a nice checklist. + +The end-of-line character depends on the system. For Unix a single <NL> +character is used. For MS-DOS, Windows, OS/2 and the like, <CR><LF> is used. +This is important when using mappings that end in a <CR>. See |:source_crnl|. + + +WHITE SPACE + +Blank lines are allowed and ignored. + +Leading whitespace characters (blanks and TABs) are always ignored. The +whitespaces between parameters (e.g. between the 'set' and the 'cpoptions' in +the example below) are reduced to one blank character and plays the role of a +separator, the whitespaces after the last (visible) character may or may not +be ignored depending on the situation, see below. + +For a ":set" command involving the "=" (equal) sign, such as in: > + + :set cpoptions =aABceFst + +the whitespace immediately before the "=" sign is ignored. But there can be +no whitespace after the "=" sign! + +To include a whitespace character in the value of an option, it must be +escaped by a "\" (backslash) as in the following example: > + + :set tags=my\ nice\ file + +The same example written as > + + :set tags=my nice file + +will issue an error, because it is interpreted as: > + + :set tags=my + :set nice + :set file + + +COMMENTS + +The character " (the double quote mark) starts a comment. Everything after +and including this character until the end-of-line is considered a comment and +is ignored, except for commands that don't consider comments, as shown in +examples below. A comment can start on any character position on the line. + +There is a little "catch" with comments for some commands. Examples: > + + :abbrev dev development " shorthand + :map <F3> o#include " insert include + :execute cmd " do it + :!ls *.c " list C files + +The abbreviation 'dev' will be expanded to 'development " shorthand'. The +mapping of <F3> will actually be the whole line after the 'o# ....' including +the '" insert include'. The "execute" command will give an error. The "!" +command will send everything after it to the shell, causing an error for an +unmatched '"' character. + There can be no comment after ":map", ":abbreviate", ":execute" and "!" +commands (there are a few more commands with this restriction). For the +":map", ":abbreviate" and ":execute" commands there is a trick: > + + :abbrev dev development|" shorthand + :map <F3> o#include|" insert include + :execute cmd |" do it + +With the '|' character the command is separated from the next one. And that +next command is only a comment. For the last command you need to do two +things: |:execute| and use '|': > + :exe '!ls *.c' |" list C files + +Notice that there is no white space before the '|' in the abbreviation and +mapping. For these commands, any character until the end-of-line or '|' is +included. As a consequence of this behavior, you don't always see that +trailing whitespace is included: > + + :map <F4> o#include + +To spot these problems, you can set the 'list' option when editing vimrc +files. + +For Unix there is one special way to comment a line, that allows making a Vim +script executable: > + #!/usr/bin/env vim -S + echo "this is a Vim script" + quit + +The "#" command by itself lists a line with the line number. Adding an +exclamation mark changes it into doing nothing, so that you can add the shell +command to execute the rest of the file. |:#!| |-S| + + +PITFALLS + +Even bigger problem arises in the following example: > + + :map ,ab o#include + :unmap ,ab + +Here the unmap command will not work, because it tries to unmap ",ab ". This +does not exist as a mapped sequence. An error will be issued, which is very +hard to identify, because the ending whitespace character in ":unmap ,ab " is +not visible. + +And this is the same as what happens when one uses a comment after an 'unmap' +command: > + + :unmap ,ab " comment + +Here the comment part will be ignored. However, Vim will try to unmap +',ab ', which does not exist. Rewrite it as: > + + :unmap ,ab| " comment + + +RESTORING THE VIEW + +Sometimes you want to make a change and go back to where cursor was. +Restoring the relative position would also be nice, so that the same line +appears at the top of the window. + This example yanks the current line, puts it above the first line in the +file and then restores the view: > + + map ,p ma"aYHmbgg"aP`bzt`a + +What this does: > + ma"aYHmbgg"aP`bzt`a +< ma set mark a at cursor position + "aY yank current line into register a + Hmb go to top line in window and set mark b there + gg go to first line in file + "aP put the yanked line above it + `b go back to top line in display + zt position the text in the window as before + `a go back to saved cursor position + + +PACKAGING + +To avoid your function names to interfere with functions that you get from +others, use this scheme: +- Prepend a unique string before each function name. I often use an + abbreviation. For example, "OW_" is used for the option window functions. +- Put the definition of your functions together in a file. Set a global + variable to indicate that the functions have been loaded. When sourcing the + file again, first unload the functions. +Example: > + + " This is the XXX package + + if exists("XXX_loaded") + delfun XXX_one + delfun XXX_two + endif + + function XXX_one(a) + ... body of function ... + endfun + + function XXX_two(b) + ... body of function ... + endfun + + let XXX_loaded = 1 + +============================================================================== +*41.11* Writing a plugin *write-plugin* + +You can write a Vim script in such a way that many people can use it. This is +called a plugin. Vim users can drop your script in their plugin directory and +use its features right away |add-plugin|. + +There are actually two types of plugins: + + global plugins: For all types of files. +filetype plugins: Only for files of a specific type. + +In this section the first type is explained. Most items are also relevant for +writing filetype plugins. The specifics for filetype plugins are in the next +section |write-filetype-plugin|. + + +NAME + +First of all you must choose a name for your plugin. The features provided +by the plugin should be clear from its name. And it should be unlikely that +someone else writes a plugin with the same name but which does something +different. And please limit the name to 8 characters, to avoid problems on +old Windows systems. + +A script that corrects typing mistakes could be called "typecorr.vim". We +will use it here as an example. + +For the plugin to work for everybody, it should follow a few guidelines. This +will be explained step-by-step. The complete example plugin is at the end. + + +BODY + +Let's start with the body of the plugin, the lines that do the actual work: > + + 14 iabbrev teh the + 15 iabbrev otehr other + 16 iabbrev wnat want + 17 iabbrev synchronisation + 18 \ synchronization + 19 let s:count = 4 + +The actual list should be much longer, of course. + +The line numbers have only been added to explain a few things, don't put them +in your plugin file! + + +HEADER + +You will probably add new corrections to the plugin and soon have several +versions laying around. And when distributing this file, people will want to +know who wrote this wonderful plugin and where they can send remarks. +Therefore, put a header at the top of your plugin: > + + 1 " Vim global plugin for correcting typing mistakes + 2 " Last Change: 2000 Oct 15 + 3 " Maintainer: Bram Moolenaar <Bram@vim.org> + +About copyright and licensing: Since plugins are very useful and it's hardly +worth restricting their distribution, please consider making your plugin +either public domain or use the Vim |license|. A short note about this near +the top of the plugin should be sufficient. Example: > + + 4 " License: This file is placed in the public domain. + + +LINE CONTINUATION, AVOIDING SIDE EFFECTS *use-cpo-save* + +In line 18 above, the line-continuation mechanism is used |line-continuation|. +Users with 'compatible' set will run into trouble here, they will get an error +message. We can't just reset 'compatible', because that has a lot of side +effects. To avoid this, we will set the 'cpoptions' option to its Vim default +value and restore it later. That will allow the use of line-continuation and +make the script work for most people. It is done like this: > + + 11 let s:save_cpo = &cpo + 12 set cpo&vim + .. + 42 let &cpo = s:save_cpo + +We first store the old value of 'cpoptions' in the s:save_cpo variable. At +the end of the plugin this value is restored. + +Notice that a script-local variable is used |s:var|. A global variable could +already be in use for something else. Always use script-local variables for +things that are only used in the script. + + +NOT LOADING + +It's possible that a user doesn't always want to load this plugin. Or the +system administrator has dropped it in the system-wide plugin directory, but a +user has his own plugin he wants to use. Then the user must have a chance to +disable loading this specific plugin. This will make it possible: > + + 6 if exists("g:loaded_typecorr") + 7 finish + 8 endif + 9 let g:loaded_typecorr = 1 + +This also avoids that when the script is loaded twice it would cause error +messages for redefining functions and cause trouble for autocommands that are +added twice. + +The name is recommended to start with "loaded_" and then the file name of the +plugin, literally. The "g:" is prepended just to avoid mistakes when using +the variable in a function (without "g:" it would be a variable local to the +function). + +Using "finish" stops Vim from reading the rest of the file, it's much quicker +than using if-endif around the whole file. + + +MAPPING + +Now let's make the plugin more interesting: We will add a mapping that adds a +correction for the word under the cursor. We could just pick a key sequence +for this mapping, but the user might already use it for something else. To +allow the user to define which keys a mapping in a plugin uses, the <Leader> +item can be used: > + + 22 map <unique> <Leader>a <Plug>TypecorrAdd + +The "<Plug>TypecorrAdd" thing will do the work, more about that further on. + +The user can set the "mapleader" variable to the key sequence that he wants +this mapping to start with. Thus if the user has done: > + + let mapleader = "_" + +the mapping will define "_a". If the user didn't do this, the default value +will be used, which is a backslash. Then a map for "\a" will be defined. + +Note that <unique> is used, this will cause an error message if the mapping +already happened to exist. |:map-<unique>| + +But what if the user wants to define his own key sequence? We can allow that +with this mechanism: > + + 21 if !hasmapto('<Plug>TypecorrAdd') + 22 map <unique> <Leader>a <Plug>TypecorrAdd + 23 endif + +This checks if a mapping to "<Plug>TypecorrAdd" already exists, and only +defines the mapping from "<Leader>a" if it doesn't. The user then has a +chance of putting this in his vimrc file: > + + map ,c <Plug>TypecorrAdd + +Then the mapped key sequence will be ",c" instead of "_a" or "\a". + + +PIECES + +If a script gets longer, you often want to break up the work in pieces. You +can use functions or mappings for this. But you don't want these functions +and mappings to interfere with the ones from other scripts. For example, you +could define a function Add(), but another script could try to define the same +function. To avoid this, we define the function local to the script by +prepending it with "s:". + +We will define a function that adds a new typing correction: > + + 30 function s:Add(from, correct) + 31 let to = input("type the correction for " . a:from . ": ") + 32 exe ":iabbrev " . a:from . " " . to + .. + 36 endfunction + +Now we can call the function s:Add() from within this script. If another +script also defines s:Add(), it will be local to that script and can only +be called from the script it was defined in. There can also be a global Add() +function (without the "s:"), which is again another function. + +<SID> can be used with mappings. It generates a script ID, which identifies +the current script. In our typing correction plugin we use it like this: > + + 24 noremap <unique> <script> <Plug>TypecorrAdd <SID>Add + .. + 28 noremap <SID>Add :call <SID>Add(expand("<cword>"), 1)<CR> + +Thus when a user types "\a", this sequence is invoked: > + + \a -> <Plug>TypecorrAdd -> <SID>Add -> :call <SID>Add() + +If another script would also map <SID>Add, it would get another script ID and +thus define another mapping. + +Note that instead of s:Add() we use <SID>Add() here. That is because the +mapping is typed by the user, thus outside of the script. The <SID> is +translated to the script ID, so that Vim knows in which script to look for +the Add() function. + +This is a bit complicated, but it's required for the plugin to work together +with other plugins. The basic rule is that you use <SID>Add() in mappings and +s:Add() in other places (the script itself, autocommands, user commands). + +We can also add a menu entry to do the same as the mapping: > + + 26 noremenu <script> Plugin.Add\ Correction <SID>Add + +The "Plugin" menu is recommended for adding menu items for plugins. In this +case only one item is used. When adding more items, creating a submenu is +recommended. For example, "Plugin.CVS" could be used for a plugin that offers +CVS operations "Plugin.CVS.checkin", "Plugin.CVS.checkout", etc. + +Note that in line 28 ":noremap" is used to avoid that any other mappings cause +trouble. Someone may have remapped ":call", for example. In line 24 we also +use ":noremap", but we do want "<SID>Add" to be remapped. This is why +"<script>" is used here. This only allows mappings which are local to the +script. |:map-<script>| The same is done in line 26 for ":noremenu". +|:menu-<script>| + + +<SID> AND <Plug> *using-<Plug>* + +Both <SID> and <Plug> are used to avoid that mappings of typed keys interfere +with mappings that are only to be used from other mappings. Note the +difference between using <SID> and <Plug>: + +<Plug> is visible outside of the script. It is used for mappings which the + user might want to map a key sequence to. <Plug> is a special code + that a typed key will never produce. + To make it very unlikely that other plugins use the same sequence of + characters, use this structure: <Plug> scriptname mapname + In our example the scriptname is "Typecorr" and the mapname is "Add". + This results in "<Plug>TypecorrAdd". Only the first character of + scriptname and mapname is uppercase, so that we can see where mapname + starts. + +<SID> is the script ID, a unique identifier for a script. + Internally Vim translates <SID> to "<SNR>123_", where "123" can be any + number. Thus a function "<SID>Add()" will have a name "<SNR>11_Add()" + in one script, and "<SNR>22_Add()" in another. You can see this if + you use the ":function" command to get a list of functions. The + translation of <SID> in mappings is exactly the same, that's how you + can call a script-local function from a mapping. + + +USER COMMAND + +Now let's add a user command to add a correction: > + + 38 if !exists(":Correct") + 39 command -nargs=1 Correct :call s:Add(<q-args>, 0) + 40 endif + +The user command is defined only if no command with the same name already +exists. Otherwise we would get an error here. Overriding the existing user +command with ":command!" is not a good idea, this would probably make the user +wonder why the command he defined himself doesn't work. |:command| + + +SCRIPT VARIABLES + +When a variable starts with "s:" it is a script variable. It can only be used +inside a script. Outside the script it's not visible. This avoids trouble +with using the same variable name in different scripts. The variables will be +kept as long as Vim is running. And the same variables are used when sourcing +the same script again. |s:var| + +The fun is that these variables can also be used in functions, autocommands +and user commands that are defined in the script. In our example we can add +a few lines to count the number of corrections: > + + 19 let s:count = 4 + .. + 30 function s:Add(from, correct) + .. + 34 let s:count = s:count + 1 + 35 echo s:count . " corrections now" + 36 endfunction + +First s:count is initialized to 4 in the script itself. When later the +s:Add() function is called, it increments s:count. It doesn't matter from +where the function was called, since it has been defined in the script, it +will use the local variables from this script. + + +THE RESULT + +Here is the resulting complete example: > + + 1 " Vim global plugin for correcting typing mistakes + 2 " Last Change: 2000 Oct 15 + 3 " Maintainer: Bram Moolenaar <Bram@vim.org> + 4 " License: This file is placed in the public domain. + 5 + 6 if exists("g:loaded_typecorr") + 7 finish + 8 endif + 9 let g:loaded_typecorr = 1 + 10 + 11 let s:save_cpo = &cpo + 12 set cpo&vim + 13 + 14 iabbrev teh the + 15 iabbrev otehr other + 16 iabbrev wnat want + 17 iabbrev synchronisation + 18 \ synchronization + 19 let s:count = 4 + 20 + 21 if !hasmapto('<Plug>TypecorrAdd') + 22 map <unique> <Leader>a <Plug>TypecorrAdd + 23 endif + 24 noremap <unique> <script> <Plug>TypecorrAdd <SID>Add + 25 + 26 noremenu <script> Plugin.Add\ Correction <SID>Add + 27 + 28 noremap <SID>Add :call <SID>Add(expand("<cword>"), 1)<CR> + 29 + 30 function s:Add(from, correct) + 31 let to = input("type the correction for " . a:from . ": ") + 32 exe ":iabbrev " . a:from . " " . to + 33 if a:correct | exe "normal viws\<C-R>\" \b\e" | endif + 34 let s:count = s:count + 1 + 35 echo s:count . " corrections now" + 36 endfunction + 37 + 38 if !exists(":Correct") + 39 command -nargs=1 Correct :call s:Add(<q-args>, 0) + 40 endif + 41 + 42 let &cpo = s:save_cpo + +Line 33 wasn't explained yet. It applies the new correction to the word under +the cursor. The |:normal| command is used to use the new abbreviation. Note +that mappings and abbreviations are expanded here, even though the function +was called from a mapping defined with ":noremap". + +Using "unix" for the 'fileformat' option is recommended. The Vim scripts will +then work everywhere. Scripts with 'fileformat' set to "dos" do not work on +Unix. Also see |:source_crnl|. To be sure it is set right, do this before +writing the file: > + + :set fileformat=unix + + +DOCUMENTATION *write-local-help* + +It's a good idea to also write some documentation for your plugin. Especially +when its behavior can be changed by the user. See |add-local-help| for how +they are installed. + +Here is a simple example for a plugin help file, called "typecorr.txt": > + + 1 *typecorr.txt* Plugin for correcting typing mistakes + 2 + 3 If you make typing mistakes, this plugin will have them corrected + 4 automatically. + 5 + 6 There are currently only a few corrections. Add your own if you like. + 7 + 8 Mappings: + 9 <Leader>a or <Plug>TypecorrAdd + 10 Add a correction for the word under the cursor. + 11 + 12 Commands: + 13 :Correct {word} + 14 Add a correction for {word}. + 15 + 16 *typecorr-settings* + 17 This plugin doesn't have any settings. + +The first line is actually the only one for which the format matters. It will +be extracted from the help file to be put in the "LOCAL ADDITIONS:" section of +help.txt |local-additions|. The first "*" must be in the first column of the +first line. After adding your help file do ":help" and check that the entries +line up nicely. + +You can add more tags inside ** in your help file. But be careful not to use +existing help tags. You would probably use the name of your plugin in most of +them, like "typecorr-settings" in the example. + +Using references to other parts of the help in || is recommended. This makes +it easy for the user to find associated help. + + +FILETYPE DETECTION *plugin-filetype* + +If your filetype is not already detected by Vim, you should create a filetype +detection snippet in a separate file. It is usually in the form of an +autocommand that sets the filetype when the file name matches a pattern. +Example: > + + au BufNewFile,BufRead *.foo set filetype=foofoo + +Write this single-line file as "ftdetect/foofoo.vim" in the first directory +that appears in 'runtimepath'. For Unix that would be +"~/.vim/ftdetect/foofoo.vim". The convention is to use the name of the +filetype for the script name. + +You can make more complicated checks if you like, for example to inspect the +contents of the file to recognize the language. Also see |new-filetype|. + + +SUMMARY *plugin-special* + +Summary of special things to use in a plugin: + +s:name Variables local to the script. + +<SID> Script-ID, used for mappings and functions local to + the script. + +hasmapto() Function to test if the user already defined a mapping + for functionality the script offers. + +<Leader> Value of "mapleader", which the user defines as the + keys that plugin mappings start with. + +:map <unique> Give a warning if a mapping already exists. + +:noremap <script> Use only mappings local to the script, not global + mappings. + +exists(":Cmd") Check if a user command already exists. + +============================================================================== +*41.12* Writing a filetype plugin *write-filetype-plugin* *ftplugin* + +A filetype plugin is like a global plugin, except that it sets options and +defines mappings for the current buffer only. See |add-filetype-plugin| for +how this type of plugin is used. + +First read the section on global plugins above |41.11|. All that is said there +also applies to filetype plugins. There are a few extras, which are explained +here. The essential thing is that a filetype plugin should only have an +effect on the current buffer. + + +DISABLING + +If you are writing a filetype plugin to be used by many people, they need a +chance to disable loading it. Put this at the top of the plugin: > + + " Only do this when not done yet for this buffer + if exists("b:did_ftplugin") + finish + endif + let b:did_ftplugin = 1 + +This also needs to be used to avoid that the same plugin is executed twice for +the same buffer (happens when using an ":edit" command without arguments). + +Now users can disable loading the default plugin completely by making a +filetype plugin with only this line: > + + let b:did_ftplugin = 1 + +This does require that the filetype plugin directory comes before $VIMRUNTIME +in 'runtimepath'! + +If you do want to use the default plugin, but overrule one of the settings, +you can write the different setting in a script: > + + setlocal textwidth=70 + +Now write this in the "after" directory, so that it gets sourced after the +distributed "vim.vim" ftplugin |after-directory|. For Unix this would be +"~/.vim/after/ftplugin/vim.vim". Note that the default plugin will have set +"b:did_ftplugin", but it is ignored here. + + +OPTIONS + +To make sure the filetype plugin only affects the current buffer use the > + + :setlocal + +command to set options. And only set options which are local to a buffer (see +the help for the option to check that). When using |:setlocal| for global +options or options local to a window, the value will change for many buffers, +and that is not what a filetype plugin should do. + +When an option has a value that is a list of flags or items, consider using +"+=" and "-=" to keep the existing value. Be aware that the user may have +changed an option value already. First resetting to the default value and +then changing it often a good idea. Example: > + + :setlocal formatoptions& formatoptions+=ro + + +MAPPINGS + +To make sure mappings will only work in the current buffer use the > + + :map <buffer> + +command. This needs to be combined with the two-step mapping explained above. +An example of how to define functionality in a filetype plugin: > + + if !hasmapto('<Plug>JavaImport') + map <buffer> <unique> <LocalLeader>i <Plug>JavaImport + endif + noremap <buffer> <unique> <Plug>JavaImport oimport ""<Left><Esc> + +|hasmapto()| is used to check if the user has already defined a map to +<Plug>JavaImport. If not, then the filetype plugin defines the default +mapping. This starts with |<LocalLeader>|, which allows the user to select +the key(s) he wants filetype plugin mappings to start with. The default is a +backslash. +"<unique>" is used to give an error message if the mapping already exists or +overlaps with an existing mapping. +|:noremap| is used to avoid that any other mappings that the user has defined +interferes. You might want to use ":noremap <script>" to allow remapping +mappings defined in this script that start with <SID>. + +The user must have a chance to disable the mappings in a filetype plugin, +without disabling everything. Here is an example of how this is done for a +plugin for the mail filetype: > + + " Add mappings, unless the user didn't want this. + if !exists("no_plugin_maps") && !exists("no_mail_maps") + " Quote text by inserting "> " + if !hasmapto('<Plug>MailQuote') + vmap <buffer> <LocalLeader>q <Plug>MailQuote + nmap <buffer> <LocalLeader>q <Plug>MailQuote + endif + vnoremap <buffer> <Plug>MailQuote :s/^/> /<CR> + nnoremap <buffer> <Plug>MailQuote :.,$s/^/> /<CR> + endif + +Two global variables are used: +no_plugin_maps disables mappings for all filetype plugins +no_mail_maps disables mappings for a specific filetype + + +USER COMMANDS + +To add a user command for a specific file type, so that it can only be used in +one buffer, use the "-buffer" argument to |:command|. Example: > + + :command -buffer Make make %:r.s + + +VARIABLES + +A filetype plugin will be sourced for each buffer of the type it's for. Local +script variables |s:var| will be shared between all invocations. Use local +buffer variables |b:var| if you want a variable specifically for one buffer. + + +FUNCTIONS + +When defining a function, this only needs to be done once. But the filetype +plugin will be sourced every time a file with this filetype will be opened. +This construct makes sure the function is only defined once: > + + :if !exists("*s:Func") + : function s:Func(arg) + : ... + : endfunction + :endif +< + +UNDO *undo_ftplugin* + +When the user does ":setfiletype xyz" the effect of the previous filetype +should be undone. Set the b:undo_ftplugin variable to the commands that will +undo the settings in your filetype plugin. Example: > + + let b:undo_ftplugin = "setlocal fo< com< tw< commentstring<" + \ . "| unlet b:match_ignorecase b:match_words b:match_skip" + +Using ":setlocal" with "<" after the option name resets the option to its +global value. That is mostly the best way to reset the option value. + +This does require removing the "C" flag from 'cpoptions' to allow line +continuation, as mentioned above |use-cpo-save|. + + +FILE NAME + +The filetype must be included in the file name |ftplugin-name|. Use one of +these three forms: + + .../ftplugin/stuff.vim + .../ftplugin/stuff_foo.vim + .../ftplugin/stuff/bar.vim + +"stuff" is the filetype, "foo" and "bar" are arbitrary names. + + +SUMMARY *ftplugin-special* + +Summary of special things to use in a filetype plugin: + +<LocalLeader> Value of "maplocalleader", which the user defines as + the keys that filetype plugin mappings start with. + +:map <buffer> Define a mapping local to the buffer. + +:noremap <script> Only remap mappings defined in this script that start + with <SID>. + +:setlocal Set an option for the current buffer only. + +:command -buffer Define a user command local to the buffer. + +exists("*s:Func") Check if a function was already defined. + +Also see |plugin-special|, the special things used for all plugins. + +============================================================================== +*41.13* Writing a compiler plugin *write-compiler-plugin* + +A compiler plugin sets options for use with a specific compiler. The user can +load it with the |:compiler| command. The main use is to set the +'errorformat' and 'makeprg' options. + +Easiest is to have a look at examples. This command will edit all the default +compiler plugins: > + + :next $VIMRUNTIME/compiler/*.vim + +Use |:next| to go to the next plugin file. + +There are two special items about these files. First is a mechanism to allow +a user to overrule or add to the default file. The default files start with: > + + :if exists("current_compiler") + : finish + :endif + :let current_compiler = "mine" + +When you write a compiler file and put it in your personal runtime directory +(e.g., ~/.vim/compiler for Unix), you set the "current_compiler" variable to +make the default file skip the settings. + *:CompilerSet* +The second mechanism is to use ":set" for ":compiler!" and ":setlocal" for +":compiler". Vim defines the ":CompilerSet" user command for this. However, +older Vim versions don't, thus your plugin should define it then. This is an +example: > + + if exists(":CompilerSet") != 2 + command -nargs=* CompilerSet setlocal <args> + endif + CompilerSet errorformat& " use the default 'errorformat' + CompilerSet makeprg=nmake + +When you write a compiler plugin for the Vim distribution or for a system-wide +runtime directory, use the mechanism mentioned above. When +"current_compiler" was already set by a user plugin nothing will be done. + +When you write a compiler plugin to overrule settings from a default plugin, +don't check "current_compiler". This plugin is supposed to be loaded +last, thus it should be in a directory at the end of 'runtimepath'. For Unix +that could be ~/.vim/after/compiler. + +============================================================================== +*41.14* Writing a plugin that loads quickly *write-plugin-quickload* + +A plugin may grow and become quite long. The startup delay may become +noticeable, while you hardly ever use the plugin. Then it's time for a +quickload plugin. + +The basic idea is that the plugin is loaded twice. The first time user +commands and mappings are defined that offer the functionality. The second +time the functions that implement the functionality are defined. + +It may sound surprising that quickload means loading a script twice. What we +mean is that it loads quickly the first time, postponing the bulk of the +script to the second time, which only happens when you actually use it. When +you always use the functionality it actually gets slower! + +Note that since Vim 7 there is an alternative: use the |autoload| +functionality |41.15|. + +The following example shows how it's done: > + + " Vim global plugin for demonstrating quick loading + " Last Change: 2005 Feb 25 + " Maintainer: Bram Moolenaar <Bram@vim.org> + " License: This file is placed in the public domain. + + if !exists("s:did_load") + command -nargs=* BNRead call BufNetRead(<f-args>) + map <F19> :call BufNetWrite('something')<CR> + + let s:did_load = 1 + exe 'au FuncUndefined BufNet* source ' . expand('<sfile>') + finish + endif + + function BufNetRead(...) + echo 'BufNetRead(' . string(a:000) . ')' + " read functionality here + endfunction + + function BufNetWrite(...) + echo 'BufNetWrite(' . string(a:000) . ')' + " write functionality here + endfunction + +When the script is first loaded "s:did_load" is not set. The commands between +the "if" and "endif" will be executed. This ends in a |:finish| command, thus +the rest of the script is not executed. + +The second time the script is loaded "s:did_load" exists and the commands +after the "endif" are executed. This defines the (possible long) +BufNetRead() and BufNetWrite() functions. + +If you drop this script in your plugin directory Vim will execute it on +startup. This is the sequence of events that happens: + +1. The "BNRead" command is defined and the <F19> key is mapped when the script + is sourced at startup. A |FuncUndefined| autocommand is defined. The + ":finish" command causes the script to terminate early. + +2. The user types the BNRead command or presses the <F19> key. The + BufNetRead() or BufNetWrite() function will be called. + +3. Vim can't find the function and triggers the |FuncUndefined| autocommand + event. Since the pattern "BufNet*" matches the invoked function, the + command "source fname" will be executed. "fname" will be equal to the name + of the script, no matter where it is located, because it comes from + expanding "<sfile>" (see |expand()|). + +4. The script is sourced again, the "s:did_load" variable exists and the + functions are defined. + +Notice that the functions that are loaded afterwards match the pattern in the +|FuncUndefined| autocommand. You must make sure that no other plugin defines +functions that match this pattern. + +============================================================================== +*41.15* Writing library scripts *write-library-script* + +Some functionality will be required in several places. When this becomes more +than a few lines you will want to put it in one script and use it from many +scripts. We will call that one script a library script. + +Manually loading a library script is possible, so long as you avoid loading it +when it's already done. You can do this with the |exists()| function. +Example: > + + if !exists('*MyLibFunction') + runtime library/mylibscript.vim + endif + call MyLibFunction(arg) + +Here you need to know that MyLibFunction() is defined in a script +"library/mylibscript.vim" in one of the directories in 'runtimepath'. + +To make this a bit simpler Vim offers the autoload mechanism. Then the +example looks like this: > + + call mylib#myfunction(arg) + +That's a lot simpler, isn't it? Vim will recognize the function name and when +it's not defined search for the script "autoload/mylib.vim" in 'runtimepath'. +That script must define the "mylib#myfunction()" function. + +You can put many other functions in the mylib.vim script, you are free to +organize your functions in library scripts. But you must use function names +where the part before the '#' matches the script name. Otherwise Vim would +not know what script to load. + +If you get really enthusiastic and write lots of library scripts, you may +want to use subdirectories. Example: > + + call netlib#ftp#read('somefile') + +For Unix the library script used for this could be: + + ~/.vim/autoload/netlib/ftp.vim + +Where the function is defined like this: > + + function netlib#ftp#read(fname) + " Read the file fname through ftp + endfunction + +Notice that the name the function is defined with is exactly the same as the +name used for calling the function. And the part before the last '#' +exactly matches the subdirectory and script name. + +You can use the same mechanism for variables: > + + let weekdays = dutch#weekdays + +This will load the script "autoload/dutch.vim", which should contain something +like: > + + let dutch#weekdays = ['zondag', 'maandag', 'dinsdag', 'woensdag', + \ 'donderdag', 'vrijdag', 'zaterdag'] + +Further reading: |autoload|. + +============================================================================== +*41.16* Distributing Vim scripts *distribute-script* + +Vim users will look for scripts on the Vim website: http://www.vim.org. +If you made something that is useful for others, share it! + +Vim scripts can be used on any system. There might not be a tar or gzip +command. If you want to pack files together and/or compress them the "zip" +utility is recommended. + +For utmost portability use Vim itself to pack scripts together. This can be +done with the Vimball utility. See |vimball|. + +It's good if you add a line to allow automatic updating. See |glvs-plugins|. + +============================================================================== + +Next chapter: |usr_42.txt| Add new menus + +Copyright: see |manual-copyright| vim:tw=78:ts=8:ft=help:norl: |