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diff --git a/runtime/doc/usr_41.txt b/runtime/doc/usr_41.txt new file mode 100644 index 0000000..4e0cc48 --- /dev/null +++ b/runtime/doc/usr_41.txt @@ -0,0 +1,1900 @@ +*usr_41.txt* For Vim version 9.0. Last change: 2023 Jan 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, therefore 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| White space +|41.10| Line continuation +|41.11| Comments +|41.12| Fileformat + + 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 the values you +prefer, define mappings, select plugins and much more. 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. + +Vim script comes in two flavors: legacy and |Vim9|. Since this help file is +for new users, we'll teach you the newer and more convenient |Vim9| syntax. +While legacy script is particularly for Vim, |Vim9| script looks more like +other languages, such as JavaScript and TypeScript. + +To try out Vim script the best way is to edit a script file and source it. +Basically: > + :edit test.vim + [insert the script lines you want] + :w + :source % + +Let's start with a simple example: > + + vim9script + var i = 1 + while i < 5 + echo "count is" i + i += 1 + endwhile +< +The output of the example code is: + + count is 1 ~ + count is 2 ~ + count is 3 ~ + count is 4 ~ + +In the first line the `vim9script` command makes clear this is a new, |Vim9| +script file. That matters for how the rest of the file is used. It is +recommended to put it in the very fist line, before any comments. + *vim9-declarations* +The `var i = 1` command declares the "i" variable and initializes it. The +generic form is: > + + var {name} = {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 `i += 1` command. This does the same thing as "i = i + 1", +it 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 $"count is {i}" + endfor + +We won't explain how `for`, `range()`and `$"string"` work until later. Follow +the links if you are impatient. + + +TRYING OUT EXAMPLES + +You can easily try out most examples in these help files without saving the +commands to a file. For example, to try out the "for" loop above do this: +1. position the cursor on the "for" +2. start Visual mode with "v" +3. move down to the "endfor" +4. press colon, then "so" and Enter + +After pressing colon you will see ":'<,'>", which is the range of the Visually +selected text. + +For some commands it matters they are executed as in |Vim9| script. But typed +commands normally use legacy script syntax, such as the example below that +causes the E1004 error. For that use this fourth step: +4. press colon, then "vim9 so" and Enter + +"vim9" is short for `vim9cmd`, which is a command modifier to execute the +following command in |Vim9| syntax. + +Note that this won't work for examples that require a script context. + + +FOUR KINDS OF NUMBERS + +Numbers can be decimal, hexadecimal, octal and binary. + +A hexadecimal number starts with "0x" or "0X". For example "0x1f" is decimal +31 and "0x1234" is decimal 4660. + +An octal number starts with "0o", "0O". "0o17" is decimal 15. + +A binary number starts with "0b" or "0B". For example "0b101" is decimal 5. + +A decimal number is just digits. Careful: In legacy script don't put a zero +before a decimal number, it will be interpreted as an octal number! That's +one reason to use |Vim9| script. + +The `echo` command evaluates its argument and when it is a number always +prints the decimal form. Example: > + + echo 0x7f 0o36 +< 127 30 ~ + +A number is made negative with a minus sign. This also works for hexadecimal, +octal and binary numbers: > + + echo -0x7f +< -127 ~ + +A minus sign is also used for subtraction. This can sometimes lead to +confusion. If we put a minus sign before both numbers we get an error: > + + echo -0x7f -0o36 +< E1004: White space required before and after '-' at "-0o36" ~ + +Note: if you are not using a |Vim9| script to try out these commands but type +them directly, they will be executed as legacy script. Then the echo command +sees the second minus sign as subtraction. To get the error, prefix the +command with `vim9cmd`: > + + vim9cmd echo -0x7f -0o36 +< E1004: White space required before and after '-' at "-0o36" ~ + +White space in an expression is often required to make sure it is easy to read +and avoid errors. Such as thinking that the "-0o36" above makes the number +negative, while it is actually seen as a subtraction. + +To actually have the minus sign be used for negation, you can put the second +expression in parentheses: > + + echo -0x7f (-0o36) +< -127 -30 ~ + +============================================================================== +*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 + CamelCaseName + LENGTH + +Invalid names are "foo.bar" and "6var". + +Some variables are global. To see a list of currently defined global +variables type this command: > + + :let + +You can use global variables everywhere. However, it is too easy to use the +same name in two unrelated scripts. Therefore variables declared in a script +are local to that script. For example, if you have this in "script1.vim": > + + vim9script + var counter = 5 + echo counter +< 5 ~ + +And you try to use the variable in "script2.vim": > + + vim9script + echo counter +< E121: Undefined variable: counter ~ + +Using a script-local variable means you can be sure that it is only changed in +that script and not elsewhere. + +If you do want to share variables between scripts, use the "g:" prefix and +assign the value directly, do not use `var`. And use a specific name to avoid +mistakes. Thus in "script1.vim": > + + vim9script + g:mash_counter = 5 + echo g:mash_counter +< 5 ~ + +And then in "script2.vim": > + + vim9script + echo g:mash_counter +< 5 ~ + +Global variables can also be accessed on the command line, E.g. typing this: > + echo g:mash_counter +That will not work for a script-local variable. + +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 global variable use the `unlet` command. Example: > + + unlet g:counter + +This deletes the global variable "g:counter" 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! g:counter + +You cannot `unlet` script-local variables in |Vim9| script, only in legacy +script. + +When a script has been processed to the end, the local variables declared +there will not be deleted. Functions defined in the script can use them. +Example: +> + vim9script + var counter = 0 + def g:GetCount(): number + counter += 1 + return counter + enddef + +Every time you call the function it will return the next count: > + :echo g:GetCount() +< 1 ~ +> + :echo g:GetCount() +< 2 ~ + +If you are worried a script-local variable is consuming too much memory, set +it to an empty or null value after you no longer need it. Example: > + var lines = readfile(...) + ... + lines = [] + +Note: below we'll leave out the `vim9script` line from examples, so we can +concentrate on the relevant commands, but you'll still need to put it at the +top of your script file. + + +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. +Example: > + + var name = "Peter" + echo name +< Peter ~ + +Every variable has a type. Very often, as in this example, the type is +defined by assigning a value. This is called type inference. If you do not +want to give the variable a value yet, you need to specify the type: > + + var name: string + var age: number + if male + name = "Peter" + age = 42 + else + name = "Elisa" + age = 45 + endif + +If you make a mistake and try to assign the wrong type of value you'll get an +error: > + + age = "Peter" +< E1012: Type mismatch; expected number but got string ~ + +More about types in |41.8|. + +To assign a string value to a variable, you can use a string constant. There +are two types of these. First the string in double quotes, as we used +already. If you want to include a double quote inside the string, put a +backslash in front of it: > + + var name = "he is \"Peter\"" + echo name +< he is "Peter" ~ + +To avoid the need for backslashes, you can use a string in single quotes: > + + var name = 'he is "Peter"' + echo name +< he is "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: > + + var name = 'P\e''ter''' + echo name +< P\e'ter' ~ + +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 fairly standard 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 value + @r register contents + +Examples: > + + echo "The value of 'tabstop' is" &ts + echo "Your home directory is" $HOME + if @a == 'text' + +The &name form can also be used to set an option value, do something and +restore the old value. Example: > + + var save_ic = &ic + set noic + s/The Start/The Beginning/ + &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 parentheses. No surprises here. Example: > + + echo (10 + 5) * 2 +< 30 ~ + + +OTHERS + +Strings can be concatenated with ".." (see |expr6|). Example: > + + echo "Name: " .. name + Name: Peter + +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. + +If you don't like the concatenation you can use the $"string" form, which +accepts an expression in curly braces: > + echo $"Name: {name}" + +See |interpolated-string| for more information. + +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: > + + var nr = 4 + echo nr > 5 ? "nr is big" : "nr is small" +< nr is small ~ + +The three parts of the constructs are always evaluated first, thus you could +see it works as: > + + (a) ? (b) : (c) + +There is also the falsy operator: > + echo name ?? "No name given" +See |??|. + +============================================================================== +*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 or one will the +{statements} be executed. If they are not executed they must still be valid +commands. If they contain garbage, Vim won't be able to find the matching +`endif`. + +You can also use `else`. The generic form for this is: + + if {condition} + {statements} + else + {statements} + endif + +The second {statements} block 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 + +This uses "#" to start a comment, more about that later. + + +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 true if the condition is met and false otherwise. An example: > + + if v:version >= 800 + 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. 800 is for version 8.0, version 8.1 has the value 801. This is +useful to write a script that works with multiple versions of Vim. +See |v:version|. You can also check for a specific feature with `has()` or a +specific patch, see |has-patch|. + +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. + +If you try to compare a string with a number you will get an error. + +For strings there are two more useful items: + + str =~ pat matches with + str !~ pat does not match with + +The left item "str" is used as a string. The right item "pat" 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 patterns tend to contain many backslashes and backslashes need to be +doubled in a double-quote string. + +The match is not anchored, if you want to match the whole string start with +"^" and end with "$". + +The 'ignorecase' option is not used when comparing strings. When you do want +to ignore case append "?". Thus "==?" compares two strings to be equal while +ignoring case. 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: > + + var counter = 1 + while counter < 40 + if skip_number(counter) + continue + endif + if last_number(counter) + break + endif + sleep 50m + ++counter + endwhile + +The `sleep` command makes Vim take a nap. The "50m" specifies fifty +milliseconds. Another example is `sleep 4`, which sleeps for four seconds. + +`continue` and `break` can also be used in between `for` and `endfor`. +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 Ex 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 with "gg" and formats all lines with the "=" +operator and the "G" movement. + +To make `normal` work with an expression, combine `execute` with it. +Example: > + + execute "normal " .. count .. "j" + +This will move the cursor "count" lines down. + +Make sure that the argument for `normal` is a complete command. Otherwise +Vim will run into the end of the argument and silently abort the command. For +example, if you start the delete operator, you must give the movement command +also. This works: > + + normal d$ + +This does nothing: > + + normal d + +If you start Insert mode and do not end it with Esc, it will end anyway. This +works to insert "new text": > + + execute "normal inew text" + +If you want to do something after inserting text you do need to end Insert +mode: > + + execute "normal inew text\<Esc>b" + +This inserts "new text" and puts the cursor on the first letter of "text". +Notice the use of the special key "\<Esc>". This avoids having to enter a +real <Esc> character in your script. That is where `execute` with a +double-quote string comes in handy. + +If you don't want to execute a string as a command but evaluate it to get the +result of the expression, you can use the eval() function: > + + var optname = "path" + var optvalue = 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. + +============================================================================== +*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 below: |function-list|. + +A function is called with the parameters in between parentheses, separated by +commas. Example: > + + 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. + +Using the `call` command is optional in |Vim9| script. It is required in +legacy script and on the command line: > + + call search("Date: ", "W") + +A function can be called in an expression. Example: > + + var line = getline(".") + var repl = substitute(line, '\a', "*", "g") + 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 "line" is the string on which to perform the substitution. +The second argument '\a' is the pattern, the third "*" is the replacement +string. Finally, the last argument "g" is 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 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: |builtin-function-list|. +Use CTRL-] on the function name to jump to detailed help on it. + +String manipulation: *string-functions* + nr2char() get a character by its number value + list2str() get a character string from a list of numbers + char2nr() get number value of a character + str2list() get list of numbers from a string + 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 + keytrans() translate internal keycodes to a form that + can be used by |:map| + tolower() turn a string to lowercase + toupper() turn a string to uppercase + charclass() class of a character + match() position where a pattern matches in a string + matchend() position where a pattern match ends in a string + matchfuzzy() fuzzy matches a string in a list of strings + matchfuzzypos() fuzzy matches a string in a list of strings + matchstr() match of a pattern in a string + matchstrpos() match and positions 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 in bytes + strcharlen() length of a string in characters + strchars() number of characters in a string + strwidth() size of string when displayed + strdisplaywidth() size of string when displayed, deals with tabs + setcellwidths() set character cell width overrides + getcellwidths() get character cell width overrides + substitute() substitute a pattern match with a string + submatch() get a specific match in ":s" and substitute() + strpart() get part of a string using byte index + strcharpart() get part of a string using char index + slice() take a slice of a string, using char index in + Vim9 script + strgetchar() get character from a string using char index + expand() expand special keywords + expandcmd() expand a command like done for `:edit` + iconv() convert text from one encoding to another + byteidx() byte index of a character in a string + byteidxcomp() like byteidx() but count composing characters + charidx() character index of a byte in a string + repeat() repeat a string multiple times + eval() evaluate a string expression + execute() execute an Ex command and get the output + win_execute() like execute() but in a specified window + trim() trim characters from a string + gettext() lookup message translation + +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 + extendnew() make a new List and append items + 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 + mapnew() make a new List with changed items + reduce() reduce a List to a value + slice() take a slice of a List + sort() sort a List + reverse() reverse the order of a List or Blob + uniq() remove copies of repeated adjacent items + 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 or Blob + indexof() index in a List or Blob where an expression + evaluates to true + 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 + flatten() flatten a List + flattennew() flatten a copy of a List + +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 + extendnew() make a new Dictionary and append items + filter() remove selected entries from a Dictionary + map() change each Dictionary entry + mapnew() make a new Dictionary with changed items + 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 + fmod() remainder of division + exp() exponential + log() natural logarithm (logarithm to base e) + log10() logarithm to base 10 + pow() value of x to the exponent y + sqrt() square root + sin() sine + cos() cosine + tan() tangent + asin() arc sine + acos() arc cosine + atan() arc tangent + atan2() arc tangent + sinh() hyperbolic sine + cosh() hyperbolic cosine + tanh() hyperbolic tangent + isinf() check for infinity + isnan() check for not a number + +Blob manipulation: *blob-functions* + blob2list() get a list of numbers from a blob + list2blob() get a blob from a list of numbers + +Other computation: *bitwise-function* + and() bitwise AND + invert() bitwise invert + or() bitwise OR + xor() bitwise XOR + sha256() SHA-256 hash + rand() get a pseudo-random number + srand() initialize seed used by rand() + +Variables: *var-functions* + type() type of a variable as a number + typename() type of a variable as text + islocked() check if a variable is locked + funcref() get a Funcref for a function reference + 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 + screencol() get screen column of the cursor + screenrow() get screen row of the cursor + screenpos() screen row and col of a text character + virtcol2col() byte index of a text character on screen + getcurpos() get position of the cursor + getpos() get position of cursor, mark, etc. + setpos() set position of cursor, mark, etc. + getmarklist() list of global/local marks + 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 + screenattr() get attribute at a screen line/row + screenchar() get character code at a screen line/row + screenchars() get character codes at a screen line/row + screenstring() get string of characters at a screen line/row + charcol() character number of the cursor or a mark + getcharpos() get character position of cursor, mark, etc. + setcharpos() set character position of cursor, mark, etc. + getcursorcharpos() get character position of the cursor + setcursorcharpos() set character position of the cursor + +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 + searchcount() get number of matches before/after the cursor + 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 + getcharsearch() return character search information + setcharsearch() set character search information + +Working with text in another buffer: + getbufline() get a list of lines from the specified buffer + getbufoneline() get a one line from the specified buffer + setbufline() replace a line in the specified buffer + appendbufline() append a list of lines in the specified buffer + deletebufline() delete lines from a specified buffer + + *system-functions* *file-functions* +System functions and manipulation of files: + glob() expand wildcards + globpath() expand wildcards in a number of directories + glob2regpat() convert a glob pattern into a search pattern + 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 + exepath() full path of an executable program + filereadable() check if a file can be read + filewritable() check if a file can be written to + getfperm() get the permissions of a file + setfperm() set the permissions of a file + getftype() get the kind of a file + isabsolutepath() check if a path is absolute + 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| or |:tcd| + tempname() get the name of a temporary file + mkdir() create a new directory + chdir() change current working directory + delete() delete a file + rename() rename a file + system() get the result of a shell command as a string + systemlist() get the result of a shell command as a list + environ() get all environment variables + getenv() get one environment variable + setenv() set an environment variable + hostname() name of the system + readfile() read a file into a List of lines + readblob() read a file into a Blob + readdir() get a List of file names in a directory + readdirex() get a List of file information in a directory + writefile() write a List of lines or Blob 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 + strptime() convert a date/time string to time + reltime() get the current or elapsed time accurately + reltimestr() convert reltime() result to a string + reltimefloat() convert reltime() result to a Float + +Autocmds: *autocmd-functions* + autocmd_add() add a list of autocmds and groups + autocmd_delete() delete a list of autocmds and groups + autocmd_get() return a list of autocmds + + *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 + arglistid() get id of the argument list + argv() get one entry from the argument list + bufadd() add a file to the list of buffers + bufexists() check if a buffer exists + buflisted() check if a buffer exists and is listed + bufload() ensure a buffer is loaded + 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 + bufwinid() get the window ID of a specific buffer + bufwinnr() get the window number of a specific buffer + winbufnr() get the buffer number of a specific window + listener_add() add a callback to listen to changes + listener_flush() invoke listener callbacks + listener_remove() remove a listener callback + win_findbuf() find windows containing a buffer + win_getid() get window ID of a window + win_gettype() get type of window + win_gotoid() go to window with ID + win_id2tabwin() get tab and window nr from window ID + win_id2win() get window nr from window ID + win_move_separator() move window vertical separator + win_move_statusline() move window status line + win_splitmove() move window to a split of another window + getbufinfo() get a list with buffer information + gettabinfo() get a list with tab page information + getwininfo() get a list with window information + getchangelist() get a list of change list entries + getjumplist() get a list of jump list entries + swapfilelist() list of existing swap files in 'directory' + swapinfo() information about a swap file + swapname() get the swap file path of a buffer + +Command line: *command-line-functions* + getcmdcompltype() get the type of the current command line + completion + getcmdline() get the current command line + getcmdpos() get position of the cursor in the command line + getcmdscreenpos() get screen position of the cursor in the + command line + setcmdline() set the current command line + setcmdpos() set position of the cursor in the command line + getcmdtype() return the current command-line type + getcmdwintype() return the current command-line window type + getcompletion() list of command-line completion matches + fullcommand() get full command name + +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 + complete_info() get current completion information + pumvisible() check if the popup menu is displayed + pum_getpos() position and size of popup menu if visible + +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 + hlget() get highlight group attributes + hlset() set highlight group attributes + 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") + matchaddpos() define a list of positions to highlight + 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 + getcharstr() get a character from the user as a string + getcharmod() get modifiers for the last typed character + getmousepos() get last known mouse position + getmouseshape() get name of the current mouse shape + echoraw() output characters as-is + 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 + getwinpos() position of the Vim window + getwinposx() X position of the Vim window + getwinposy() Y position of the Vim window + balloon_show() set the balloon content + balloon_split() split a message for a balloon + balloon_gettext() get the text in the balloon + +Vim server: *server-functions* + serverlist() return the list of server names + remote_startserver() run a server + 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 + win_screenpos() get screen position of a window + winlayout() get layout of windows in a tab page + winrestcmd() return command to restore window sizes + winsaveview() get view of current window + winrestview() restore saved view of current window + +Mappings and Menus: *mapping-functions* + digraph_get() get |digraph| + digraph_getlist() get all |digraph|s + digraph_set() register |digraph| + digraph_setlist() register multiple |digraph|s + hasmapto() check if a mapping exists + mapcheck() check if a matching mapping exists + maparg() get rhs of a mapping + maplist() get list of all mappings + mapset() restore a mapping + menu_info() get information about a menu item + wildmenumode() check if the wildmode is active + +Testing: *test-functions* + assert_equal() assert that two expressions values are equal + assert_equalfile() assert that two file contents are equal + assert_notequal() assert that two expressions values are not equal + assert_inrange() assert that an expression is inside a range + assert_match() assert that a pattern matches the value + assert_notmatch() assert that a pattern does not match the value + assert_false() assert that an expression is false + assert_true() assert that an expression is true + assert_exception() assert that a command throws an exception + assert_beeps() assert that a command beeps + assert_nobeep() assert that a command does not cause a beep + assert_fails() assert that a command fails + assert_report() report a test failure + test_alloc_fail() make memory allocation fail + test_autochdir() enable 'autochdir' during startup + test_override() test with Vim internal overrides + test_garbagecollect_now() free memory right now + test_garbagecollect_soon() set a flag to free memory soon + test_getvalue() get value of an internal variable + test_gui_event() generate a GUI event for testing + test_ignore_error() ignore a specific error message + test_mswin_event() generate an MS-Windows event + test_null_blob() return a null Blob + test_null_channel() return a null Channel + test_null_dict() return a null Dict + test_null_function() return a null Funcref + test_null_job() return a null Job + test_null_list() return a null List + test_null_partial() return a null Partial function + test_null_string() return a null String + test_settime() set the time Vim uses internally + test_setmouse() set the mouse position + test_feedinput() add key sequence to input buffer + test_option_not_set() reset flag indicating option was set + test_refcount() return an expression's reference count + test_srand_seed() set the seed value for srand() + test_unknown() return a value with unknown type + test_void() return a value with void type + +Inter-process communication: *channel-functions* + ch_canread() check if there is something to read + ch_open() open a channel + ch_close() close a channel + ch_close_in() close the in part of a channel + ch_read() read a message from a channel + ch_readblob() read a Blob from a channel + ch_readraw() read a raw message from a channel + ch_sendexpr() send a JSON message over a channel + ch_sendraw() send a raw message over a channel + ch_evalexpr() evaluate an expression over channel + ch_evalraw() evaluate a raw string over channel + ch_status() get status of a channel + ch_getbufnr() get the buffer number of a channel + ch_getjob() get the job associated with a channel + ch_info() get channel information + ch_log() write a message in the channel log file + ch_logfile() set the channel log file + ch_setoptions() set the options for a channel + json_encode() encode an expression to a JSON string + json_decode() decode a JSON string to Vim types + js_encode() encode an expression to a JSON string + js_decode() decode a JSON string to Vim types + +Jobs: *job-functions* + job_start() start a job + job_stop() stop a job + job_status() get the status of a job + job_getchannel() get the channel used by a job + job_info() get information about a job + job_setoptions() set options for a job + +Signs: *sign-functions* + sign_define() define or update a sign + sign_getdefined() get a list of defined signs + sign_getplaced() get a list of placed signs + sign_jump() jump to a sign + sign_place() place a sign + sign_placelist() place a list of signs + sign_undefine() undefine a sign + sign_unplace() unplace a sign + sign_unplacelist() unplace a list of signs + +Terminal window: *terminal-functions* + term_start() open a terminal window and run a job + term_list() get the list of terminal buffers + term_sendkeys() send keystrokes to a terminal + term_wait() wait for screen to be updated + term_getjob() get the job associated with a terminal + term_scrape() get row of a terminal screen + term_getline() get a line of text from a terminal + term_getattr() get the value of attribute {what} + term_getcursor() get the cursor position of a terminal + term_getscrolled() get the scroll count of a terminal + term_getaltscreen() get the alternate screen flag + term_getsize() get the size of a terminal + term_getstatus() get the status of a terminal + term_gettitle() get the title of a terminal + term_gettty() get the tty name of a terminal + term_setansicolors() set 16 ANSI colors, used for GUI + term_getansicolors() get 16 ANSI colors, used for GUI + term_dumpdiff() display difference between two screen dumps + term_dumpload() load a terminal screen dump in a window + term_dumpwrite() dump contents of a terminal screen to a file + term_setkill() set signal to stop job in a terminal + term_setrestore() set command to restore a terminal + term_setsize() set the size of a terminal + term_setapi() set terminal JSON API function name prefix + +Popup window: *popup-window-functions* + popup_create() create popup centered in the screen + popup_atcursor() create popup just above the cursor position, + closes when the cursor moves away + popup_beval() at the position indicated by v:beval_ + variables, closes when the mouse moves away + popup_notification() show a notification for three seconds + popup_dialog() create popup centered with padding and border + popup_menu() prompt for selecting an item from a list + popup_hide() hide a popup temporarily + popup_show() show a previously hidden popup + popup_move() change the position and size of a popup + popup_setoptions() override options of a popup + popup_settext() replace the popup buffer contents + popup_close() close one popup + popup_clear() close all popups + popup_filter_menu() select from a list of items + popup_filter_yesno() block until 'y' or 'n' is pressed + popup_getoptions() get current options for a popup + popup_getpos() get actual position and size of a popup + popup_findecho() get window ID for popup used for `:echowindow` + popup_findinfo() get window ID for popup info window + popup_findpreview() get window ID for popup preview window + popup_list() get list of all popup window IDs + popup_locate() get popup window ID from its screen position + +Timers: *timer-functions* + timer_start() create a timer + timer_pause() pause or unpause a timer + timer_stop() stop a timer + timer_stopall() stop all timers + timer_info() get information about timers + +Tags: *tag-functions* + taglist() get list of matching tags + tagfiles() get a list of tags files + gettagstack() get the tag stack of a window + settagstack() modify the tag stack of a window + +Prompt Buffer: *promptbuffer-functions* + prompt_getprompt() get the effective prompt text for a buffer + prompt_setcallback() set prompt callback for a buffer + prompt_setinterrupt() set interrupt callback for a buffer + prompt_setprompt() set the prompt text for a buffer + +Registers: *register-functions* + getreg() get contents of a register + getreginfo() get information about a register + getregtype() get type of a register + setreg() set contents and type of a register + reg_executing() return the name of the register being executed + reg_recording() return the name of the register being recorded + +Text Properties: *text-property-functions* + prop_add() attach a property at a position + prop_add_list() attach a property at multiple positions + prop_clear() remove all properties from a line or lines + prop_find() search for a property + prop_list() return a list of all properties in a line + prop_remove() remove a property from a line + prop_type_add() add/define a property type + prop_type_change() change properties of a type + prop_type_delete() remove a text property type + prop_type_get() return the properties of a type + prop_type_list() return a list of all property types + +Sound: *sound-functions* + sound_clear() stop playing all sounds + sound_playevent() play an event's sound + sound_playfile() play a sound file + sound_stop() stop playing a sound + +Various: *various-functions* + mode() get current editing mode + state() get current busy state + visualmode() last visual mode used + exists() check if a variable, function, etc. exists + exists_compiled() like exists() but check at compile time + 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 + getscriptinfo() get list of sourced vim scripts + getimstatus() check if IME status is active + interrupt() interrupt script execution + windowsversion() get MS-Windows version + terminalprops() properties of the terminal + + libcall() call a function in an external library + libcallnr() idem, returning a number + + undofile() get the name of the undo file + undotree() return the state of the undo tree + + shiftwidth() effective value of 'shiftwidth' + + wordcount() get byte/word/char count of buffer + + luaeval() evaluate |Lua| expression + mzeval() evaluate |MzScheme| expression + perleval() evaluate Perl expression (|+perl|) + py3eval() evaluate Python expression (|+python3|) + pyeval() evaluate Python expression (|+python|) + pyxeval() evaluate |python_x| expression + rubyeval() evaluate |Ruby| expression + + debugbreak() interrupt a program being debugged + +============================================================================== +*41.7* Defining a function + +Vim enables you to define your own functions. The basic function declaration +begins as follows: > + + def {name}({var1}, {var2}, ...): return-type + {body} + enddef +< + 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: > + + def Min(num1: number, num2: number): number + +This tells Vim that the function is named "Min", it takes two arguments that +are numbers: "num1" and "num2" and returns a number. + +The first thing you need to do is to check to see which number is smaller: + > + if num1 < num2 + +Let's assign the variable "smaller" the value of the smallest number: > + + var smaller: number + if num1 < num2 + smaller = num1 + else + smaller = num2 + endif + +The variable "smaller" is a local variable. It is declared to be a number, +that way Vim can warn you for any mistakes. Variables used inside a function +are local unless prefixed by something like "g:", "w:", or "b:". + + 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 or the script. + +You now use the `return` statement to return the smallest number to the user. +Finally, you end the function: > + + return smaller + enddef + +The complete function definition is as follows: > + + def Min(num1: number, num2: number): number + var smaller: number + if num1 < num2 + smaller = num1 + else + smaller = num2 + endif + return smaller + enddef + +Obviously this is a verbose example. You can make it shorter by using two +return commands: > + + def Min(num1: number, num2: number): number + if num1 < num2 + return num1 + endif + return num2 + enddef + +And if you remember the conditional expression, you need only one line: > + + def Min(num1: number, num2: number): number + return num1 < num2 ? num1 : num2 + enddef + +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 parsed 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. To get the errors sooner you can tell Vim to compile all the +functions in the script: > + + defcompile + +Compiling functions takes a little time, but does report errors early. You +could use `:defcompile` at the end of your script while working on it, and +comment it out when everything is fine. + +For a function that does not return anything simply leave out the return type: > + + def SayIt(text: string) + echo text + enddef + +If you want to return any kind of value, you can use the "any" return type: > + def GetValue(): any +This disables type checking for the return value, use only when needed. + +It is also possible to define a legacy function with `function` and +`endfunction`. These do not have types and are not compiled. Therefore they +execute much slower. + + +USING A RANGE + +A line range can be used with a function call. The function will be called +once for every line in the range, with the cursor in that line. Example: > + + def Number() + echo "line " .. line(".") .. " contains: " .. getline(".") + enddef + +If you call this function with: > + + :10,15Number() + +The function will be called six times, starting on line 10 and ending on line +15. + + +LISTING FUNCTIONS + +The `function` command lists the names and arguments of all user-defined +functions: > + + :function +< def <SNR>86_Show(start: string, ...items: list<string>) ~ + function GetVimIndent() ~ + function SetSyn(name) ~ + +The "<SNR>" prefix means that a function is script-local. |Vim9| functions +will start with "def" and include argument and return types. Legacy functions +are listed with "function". + +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 ~ + +To see the "Show" function you need to include the script prefix, since +multiple "Show" functions can be defined in different scripts. To find +the exact name you can use `function`, but the result may be a very long list. +To only get the functions matching a pattern you can use the `filter` prefix: +> + :filter Show function +< def <SNR>86_Show(start: string, ...items: list<string>) ~ +> + :function <SNR>86_Show +< 1 echohl Title ~ + 2 echo "start is " .. start ~ + etc. + + +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 SetSyn() function: > + + :delfunction SetSyn + +Deleting only works for global functions and functions in legacy script, not +for functions defined in a |Vim9| script. + +You get an error when the function doesn't exist or cannot be deleted. + + +FUNCTION REFERENCES + +Sometimes it can be useful to have a variable point to one function or +another. You can do it with a function reference variable. Often shortened +to "funcref". Example: > + + def Right(): string + return 'Right!' + enddef + def Wrong(): string + return 'Wrong!' + enddef + + var Afunc = g:result == 1 ? Right : Wrong + echo Afunc() +< Wrong! ~ + +This assumes "g:result" is not one. See |Funcref| for details. + +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. + + +FURTHER READING + +Using a variable number of arguments is introduced in section |50.2|. + +More information about defining your own functions here: |user-functions|. + +============================================================================== +*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 items. The items 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: > + + var alist = ['aap', 'noot', 'mies'] + +The List items are enclosed in square brackets and separated by commas. To +create an empty List: > + + var alist = [] + +You can add items to a List with the add() function: > + + var alist = [] + add(alist, 'foo') + add(alist, 'bar') + echo alist +< ['foo', 'bar'] ~ + +List concatenation is done with +: > + + var alist = ['foo', 'bar'] + alist = alist + ['and', 'more'] + echo alist +< ['foo', 'bar', 'and', 'more'] ~ + +Or, if you want to extend a List with a function, use `extend()`: > + + var alist = ['one'] + extend(alist, ['two', 'three']) + echo alist +< ['one', 'two', 'three'] ~ + +Notice that using `add()` will have a different effect than `extend()`: > + + var alist = ['one'] + add(alist, ['two', 'three']) + echo alist +< ['one', ['two', 'three']] ~ + +The second argument of add() is added as an item, now you have a nested list. + + +FOR LOOP + +One of the nice things you can do with a List is iterate over it: > + + var alist = ['one', 'two', 'three'] + for n in alist + echo n + endfor +< one ~ + two ~ + three ~ + +This will loop over each element in List "alist", assigning each value to +variable "n". The generic form of a for loop is: > + + for {varname} in {list-expression} + {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. Detail: Internally range() +does not actually create the list, so that a large range used in a for loop +works efficiently. When used elsewhere, the range is turned into an actual +list, which takes more time for a long 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 all the lines in the buffer: > + + for line in getline(1, 50) + if line =~ "Date: " + echo line + endif + endfor + +This looks into lines 1 to 50 (inclusive) and echoes any date found in there. + +For further reading see |Lists|. + + +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: > + + var uk2nl = {one: 'een', two: 'twee', three: 'drie'} + +Now you can lookup words by putting the key in square brackets: > + + echo uk2nl['two'] +< twee ~ + +If the key does not have special characters, you can use the dot notation: > + + 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. + +For further reading see |Dictionaries|. + +============================================================================== +*41.9* White space + +Blank lines are allowed in a script and ignored. + +Leading whitespace characters (blanks and TABs) are ignored, except when using +|:let-heredoc| without "trim". + +Trailing whitespace is often ignored, but not always. One command that +includes it is `map`. You have to watch out for that, it can cause hard to +understand mistakes. A generic solution is to never use trailing white space, +unless you really need it. + +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 + +If it would be written as: > + + :set tags=my nice file + +This will issue an error, because it is interpreted as: > + + :set tags=my + :set nice + :set file + +|Vim9| script is very picky when it comes to white space. This was done +intentionally to make sure scripts are easy to read and to avoid mistakes. +If you use white space sensibly it will just work. When not you will get an +error message telling you where white space is missing or should be removed. + +============================================================================== +*41.10* Line continuation + +In legacy Vim script line continuation is done by preceding a continuation +line with a backslash: > + let mylist = [ + \ 'one', + \ 'two', + \ ] + +This requires the 'cpo' option to exclude the "C" flag. Normally this is done +by putting this at the start of the script: > + let s:save_cpo = &cpo + set cpo&vim + +And restore the option at the end of the script: > + let &cpo = s:save_cpo + unlet s:save_cpo + +A few more details can be found here: |line-continuation|. + +In |Vim9| script the backslash can still be used, but in most places it is not +needed: > + var mylist = [ + 'one', + 'two', + ] + +Also, the 'cpo' option does not need to be changed. See +|vim9-line-continuation| for details. + +============================================================================== +*41.11* Comments + +In |Vim9| script the character # starts a comment. That character and +everything after it 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, +but not when it is part of the command, e.g. inside a string. + +The character " (the double quote mark) starts a comment in legacy script. +This involves some cleverness to make sure double quoted strings are not +recognized as comments (just one reason to prefer |Vim9| script). + +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, most likely + causing an error. + +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 '!ls *.c' |# do it + +With the '|' character the command is separated from the next one. And that +next command is only a comment. The last command, using `execute` is a +general solution, it works for all commands that do not accept a comment or a +'|' to separate the next command. + +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 + +Here it is intended, in other cases it might be accidental. To spot these +problems, you can highlight trailing spaces: > + match Search /\s\+$/ + +For Unix there is one special way to comment a line, that allows making a Vim +script executable, and it also works in legacy script: > + #!/usr/bin/env vim -S + echo "this is a Vim script" + quit + +============================================================================== +*41.12* Fileformat + +The end-of-line character depends on the system. For Vim scripts it is +recommended to always use the Unix fileformat. Lines are then separated with +the Newline character. This also works on any other system. That way you can +copy your Vim scripts from MS-Windows to Unix and they still work. See +|:source_crnl|. To be sure it is set right, do this before writing the file: +> + :setlocal fileformat=unix + +When using "dos" fileformat, lines are separated with CR-NL, two characters. +The CR character causes various problems, better avoid this. + +============================================================================== + +Advance information about writing Vim script is in |usr_50.txt|. + +Next chapter: |usr_42.txt| Add new menus + +Copyright: see |manual-copyright| vim:tw=78:ts=8:noet:ft=help:norl: |