eval.txt - html version
eval.txt - html version
*eval.txt* For Vim version 5.1. Last modification: 1998 Apr 06
VIM REFERENCE MANUAL by Bram Moolenaar
Expression evaluation *expression* *expr*
Note: Expression evaluation can be disabled at compile time. If this has been
done, the features in this document are not available. See |+eval|.
1. Variables |variables|
2. Expression syntax |expression-syntax|
3. Internal variable |internal-variables|
4. Function calls |functions|
5. Commands |expression-commands|
{Vi does not have any of these commands}
1. Variables *variables*
There are two types of variables:
Number a 32 bit signed number
String a NUL terminated string of 8-bit unsigned characters.
These are converted automatically, depending on how they are used.
Conversion from a Number to a String is by making the ASCII representation of
the Number. Examples:
Number 123 --> String "123"
Number 0 --> String "0"
Number -1 --> String "-1"
Conversion from a String to a Number is done by converting the first digits
to a number. Hexadecimal "0xf9" and Octal "017" numbers are recognized. If
the String doesn't start with digits, the result is zero. Examples:
String "456" --> Number 456
String "6bar" --> Number 6
String "foo" --> Number 0
String "0xf1" --> Number 241
String "0100" --> Number 64
For boolean operators Numbers are used. Zero is FALSE, non-zero is TRUE.
Note that in the command
:if "foo"
"foo" is converted to 0, which means FALSE. To test for a non-empty string,
use strlen():
:if strlen("foo")
2. Expression syntax *expression-syntax*
Expression syntax summary, from least to most significant:
|expr1| expr2 || expr2 .. logical OR
|expr2| expr3 && expr3 .. logical AND
|expr3| expr4 == expr4 equal
expr4 != expr4 not equal
expr4 > expr4 greater than
expr4 >= expr4 greater than or equal
expr4 < expr4 smaller than
expr4 <= expr4 smaller than or equal
expr4 =~ expr4 regexp matches
expr4 !~ expr4 regexp doesn't match
|expr4| expr5 + expr5 .. number addition
expr5 - expr5 .. number subtraction
expr5 . expr5 .. string concatenation
|expr5| expr6 * expr6 .. number multiplication
expr6 / expr6 .. number division
expr6 % expr6 .. number modulo
|expr6| ! expr6 logical NOT
- expr6 unary minus
|expr7| expr8[expr1] index in String
|expr8| number number constant
"string" string constant
'string' literal string constant
&option option value
(expr1) nested expression
variable internal variable
$VAR environment variable
@r contents of register 'r'
function(expr1, expr1) function call
".." indicates that the operations in this level can be concatenated.
Example:
&nu || &list && &shell == "csh"
All expressions within one level are parsed from left to right.
expr1 and expr2 *expr1* *expr2*
*expr-barbar* *expr-&&*
The "||" and "&&" operators take one argument on each side. The arguments
are (converted to) Numbers. The result is:
input output
n1 n2 n1 || n2 n1 && n2
zero zero zero zero
zero non-zero non-zero zero
non-zero zero non-zero zero
non-zero non-zero non-zero non-zero
The operators can be concatenated, for example:
&nu || &list && &shell == "csh"
Note that "&&" takes precedence over "||", so this has the meaning of:
&nu || (&list && &shell == "csh")
All arguments are computed, there is no skipping if the value of an argument
doesn't matter, because the result is already known. This is different from
C, although it only matters for errors (unknown variables), since there are no
side effects from an expression.
expr3 *expr3*
expr4 == expr4 equal *expr-==*
expr4 != expr4 not equal *expr-!=*
expr4 > expr4 greater than *expr->*
expr4 >= expr4 greater than or equal *expr->=*
expr4 < expr4 smaller than *expr-<*
expr4 <= expr4 smaller than or equal *expr-<=*
expr4 =~ expr4 regexp matches *expr-=~*
expr4 !~ expr4 regexp doesn't match *expr-!~*
When comparing a String with a Number, the String is converted to a Number,
and the comparison is done on Numbers.
When comparing two Strings, this is done with strcmp(). This results in the
mathematical difference, not necessarily the alphabetical difference in the
local language.
The "=~" and "!~" operators match the lefthand argument with the righthand
argument, which is used as a pattern. See |pattern| for what a pattern is.
This matching is always done like 'magic' was set, no matter what the actual
value of 'magic' is. This makes scripts portable. The value of 'ignorecase'
does matter though. To avoid backslashes in the regexp pattern to be doubled,
use a single-quote string, see |literal-string|.
expr4 and expr5 *expr4* *expr5*
expr5 + expr5 .. number addition *expr-+*
expr5 - expr5 .. number subtraction *expr--*
expr5 . expr5 .. string concatenation *expr-.*
expr6 * expr6 .. number multiplication *expr-star*
expr6 / expr6 .. number division *expr-/*
expr6 % expr6 .. number modulo *expr-%*
For all, except ".", Strings are converted to Numbers.
Note the difference between "+" and ".":
"123" + "456" = 579
"123" . "456" = "123456"
When the righthand side of '/' is zero, the result is 0xfffffff.
When the righthand side of '%' is zero, the result is 0.
expr6 *expr6*
! expr6 logical NOT *expr-!*
- expr6 unary minus *expr-unary--*
For '!' non-zero becomes zero, zero becomes one.
For '-' the sign of the number is changed.
A String will be converted to a Number first.
These two can be repeated and mixed. Examples:
!-1 == 0
!!8 == 1
--9 == 9
expr7 *expr7*
expr8[expr1] index in String *expr-[]*
This results in a String that contains the expr1'th single character from
expr8. expr8 is used as a String, expr1 as a Number.
Note that index zero gives the first character. This is like it works in C.
Careful: column numbers start with one! Example, to get the character under
the cursor:
c = getline(line("."))[col(".") - 1]
If the length of the String is less than the index, the result is an empty
String.
*expr8*
number
number number constant *expr-number*
Decimal, Hexadecimal (starting with 0x or 0X), or Octal (starting with 0).
string *expr-string*
"string" string constant *expr-quote*
Note that double quotes are used.
A string constant accepts these special characters:
\... three-digit octal number (e.g., "\316")
\.. two-digit octal number (must be followed by non-digit)
\. one-digit octal number (must be followed by non-digit)
\x.. two-character hex number (e.g., "\x1f")
\x. one-character hex number (must be followed by non-hex)
\X.. same as \x..
\X. same as \x.
\b backspace <BS>
\e escape <Esc>
\f formfeed <FF>
\n newline <NL>
\r return <CR>
\t tab <Tab>
\\ backslash
\" double quote
\<xxx> Special key named "xxx". e.g. "\<C-W>" for CTRL-W.
Note that "\000" and "\x00" force the end of the string.
literal-string *literal-string*
'string' literal string constant *expr-'*
Note that single quotes are used.
This string is taken literally. No backslashes are removed or have a special
meaning. A literal-string cannot contain a single quote. Use a normal string
for that.
option *expr-option*
&option option value
Any option name can be used here. See |options|.
register *expr-register*
@r contents of register 'r'
The result is the contents of the named register, as a single string.
Newlines are inserted where required. To get the contents of the unnamed
register use @@. The '=' register can not be used here. See |registers| for
an explanation of the available registers.
nesting *expr-nesting*
(expr1) nested expression
environment variable *expr-env*
$VAR environment variable
The String value of any environment variable. When it is not defined, the
result is an empty string.
internal variable *expr-variable*
variable internal variable
See below |internal-variables|.
function call *expr-function*
function(expr1, expr1) function call
See below |functions|.
3. Internal variable *internal-variables*
An internal variable name can be made up of letters, digits and '_'. But it
cannot start with a digit.
An internal variable is created with the ":let" command |:let|.
An internal variable is destroyed with the ":unlet" command |:unlet|.
Using a name that isn't an internal variable, or an internal variable that has
been destroyed, results in an error.
A variable name that is preceded with "b:" is local to the current buffer.
A variable name that is preceded with "w:" is local to the current window.
Predefined variables:
*count-variable*
count The count given for the last Normal mode command. Can be used
to get the count before a mapping. Example:
:map _x :<C-U>echo "the count is " . count<CR>
Note: The <C-U> is required to remove the line range that you
get when typing ':' after a count. read-only.
*errmsg-variable*
errmsg Last given error message. It's allowed to set this variable.
Example:
:let errmsg = ""
:next
:if (errmsg != "")
: ...
*shell_error-variable*
shell_error Result of the last shell command. When non-zero, the last
shell command had an error. When zero, there was no problem.
This only works when the shell returns the error code to Vim.
Example:
:!mv foo bar
:if shell_error
: echo 'could not rename "foo" to "bar"!'
:endif
*version-variable*
version Version number of Vim: Major version number times 100 plus
minor version number. Version 5.0 is 500. Version 5.1 (5.01)
is 501. Read-only.
4. Function calls *functions*
USAGE RESULT DESCRIPTION
buffer_exists({expr}) Number TRUE if a buffer {exp} exists
buffer_name({expr}) String Name of the buffer {expr}
buffer_number({expr}) Number Number of the buffer {expr}
char2nr({expr}) Number ASCII value of first char in {expr}
col({expr}) Number column nr of cursor or mark
delete({expr}) Number delete file {expr}
exists({var}) Number TRUE if {var} exists
expand({expr}) String expand file wildcards in {expr}
file_readable({file}) Number TRUE if {file} is a readable file
getcwd() String the current working directory
getline({lnum}) String line {lnum} from current buffer
has({feature}) Number TRUE if feature {feature} supported
highlight_exists({name}) Number TRUE if highlight group {name} exists
highlightID({name}) Number syntax ID of highlight group {name}
hostname() String name of the machine vim is running on
isdirectory({directory}) Number TRUE if {directory} is a directory
last_buffer_nr() Number buffer number of last buffer
line({expr}) Number line nr of cursor, last line or mark
match({expr}, {pat}) Number position where {pat} matches in {expr}
matchend({expr}, {pat}) Number position where {pat} ends in {expr}
nr2char({expr}) String single char with ASCII value {expr}
strftime({expr}) String current time in specified format
strlen({expr}) Number length of the String {expr}
strpart({src}, {start}, {len}) String {len} characters of {src} at {start}
synID({line}, {col}, {trans}) Number syntax ID at {line} and {col}
synIDattr({synID}, {what}) String attribute {what} of syntax ID {synID}
synIDtrans({synID}) Number translated syntax ID of {synID}
substitute({expr}, {pat}, {sub}, {flags})
String all {pat} in {expr} replaced with {sub}
tempname() String name for a temporary file
virtcol({expr}) Number screen column of cursor or mark
winheight({nr}) Number height of window {nr}
*buffer_exists()*
buffer_exists({var})
The result is a Number, which is non-zero if a buffer called
{var} exists. If the {var} argument is a string it must match
a buffer name exactly. If the {var} argument is a number
buffer numbers are used. Use "buffer_exists(0)" to test for
the existence of an alternate file name.
*buffer_name()*
buffer_name({expr})
The result is the name of a buffer, as it is displayed by the
":ls" command.
If {expr} is a number, that buffer number's name is given.
Number zero is the alternate buffer for the current window.
If {expr} is a string, it is used as a regexp pattern to match
with the buffer names. When there is more than one match an
empty string is returned. "" or "%" can be used for the
current buffer, "#" for the alternate buffer.
If the buffer doesn't exist, or doesn't have a name, an empty
string is returned.
buffer_name("#") alternate buffer name
buffer_name(3) name of buffer 3
buffer_name("%") name of current buffer
buffer_name("file2") name of buffer where "file2" matches.
*buffer_number()*
buffer_number({expr})
The result is the number of a buffer, as it is displayed by
the ":ls" command. For the use of {expr}, see buffer_name()
above.
If the buffer doesn't exist, -1 is returned.
*char2nr()*
char2nr({expr})
Return ASCII value of the first char in {expr}. Examples:
char2nr(" ") returns 32
char2nr("ABC") returns 65
*col()*
col({expr}) The result is a Number, which is the column of the file
position given with {expr}. The accepted positions are:
. the cursor position
'x position of mark x (if the mark is not set, 0 is
returned)
Note that only marks in the current file can be used.
Examples:
col(".") column of cursor
col("'t") column of mark t
col("'" . markname) column of mark markname
The first column is 1. 0 is returned for an error.
*delete()*
delete({expr}) Deletes the file by the name {expr}. The result is a Number,
which is 0 if the file was deleted succesfully, and non-zero
when the deletion failed.
*exists()*
exists({expr}) The result is a Number, which is 1 if {var} is defined, zero
otherwise. The {expr} argument is a string, which contains
one of these:
&option-name Vim option
$ENVNAME environment variable (could also be
done by comparing with an empty
string)
varname internal variable (see
|internal-variables|).
Examples:
exists("&shortname")
exists("$HOSTNAME")
exists("bufcount")
Note that the argument must be a string, not the name of the
variable itself! This doesn't check for existence of the
"bufcount" variable, but gets the contents of "bufcount", and
checks if that exists:
exists(bufcount)
*expand()*
expand({expr}) Expand the file wildcards in {expr}. The result is a String.
When there are several matches, they are separated by <NL>
characters. [Note: in version 5.0 a space was used, which
caused problems when a file name contains a space]
For Unix, backticks can be used to get the output of any
command. Example:
:let tagfiles = expand("`find . -name tags -print`")
:let &tags = substitute(tagfiles, "\n", ",", "g")
If the expansion fails, the result is an empty string.
When the result of {expr} starts with '%', '#' or '<', the
expansion is done like for the |cmdline-special| variables
with their associated modifiers. Here is a short overview:
% current file name
# alternate file name
#n alternate file name n
<cfile> file name under the cursor
<afile> autocmd file name
<sfile> sourced script file name
<cword> word under the cursor
<cWORD> WORD under the cursor
Modifiers:
:p expand to full path
:h head (last path component removed)
:t tail (last path component only)
:r root (one extension removed)
:e extension only
Example:
:let &tags = expand("%:p:h") . "/tags"
There cannot be white space between the variables and the
following modifier.
When using '%' or '#', and the current or alternate file name
is not defined, an empty string is used. Using "%:p" in a
buffer with no name, results in the current directory, with a
'/' added.
*file_readable()*
file_readable({file})
The result is a Number, which is TRUE when a file with the
name {file} exists, and can be read. If {file} doesn't exist,
or is a directory, the result is FALSE. {file} is any
expression, which is used as a String.
*getcwd()*
getcwd() The result is a String, which is the name of the current
working directory.
*getline()*
getline({lnum}) The result is a String, which is line {lnum} from the current
buffer. Example:
getline(1)
When {lnum} is a String that doesn't start with a
digit, line() is called to translate the String into a Number.
To get the line under the cursor:
getline(".")
When {lnum} is smaller than 1 or bigger than the number of
lines in the buffer, an empty string is returned.
*has()*
has({feature}) The result is a Number, which is 1 if the feature {feature} is
supported, zero otherwise. The {feature} argument is a
string. See |feature-list| below.
*highlight_exists()*
highlight_exists({name})
The result is a Number, which is non-zero if a highlight group
called {name} exists. This is when the group has been
defined in some way. Not necessarily when highlighting has
been defined for it, it may also have been used for a syntax
item.
*highlightID()*
highlightID({name})
The result is a Number, which is the ID of the highlight group
with name {name}. When the highlight group doesn't exist,
zero is returned.
This can be used to retrieve information about the highlight
group. For example, to get the background color of the
"Comment" group:
echo synIDattr(synIDtrans(highlightID("Comment")), "bg")
*hostname()*
hostname()
The result is a String, which is the name of the machine on
which Vim is currently running. Machine names greater than
256 characters long are truncated.
*isdirectory()*
isdirectory({directory})
The result is a Number, which is TRUE when a directory with
the name {directory} exists. If {directory} doesn't exist, or
isn't a directory, the result is FALSE. {directory} is any
expression, which is used as a String.
*last_buffer_nr()*
last_buffer_nr()
The result is a Number, which is the highest buffer number
of existing buffers. Note that not all buffers with a smaller
number necessarily exist, because ":bdel" may have removed
them. Use buffer_exists() to test for the existence of a
buffer.
*line()*
line({expr}) The result is a Number, which is the line number of the file
position given with {expr}. The accepted positions are:
. the cursor position
$ the last line in the current buffer
'x position of mark x (if the mark is not set, 0 is
returned)
Note that only marks in the current file can be used.
Examples:
line(".") line number of the cursor
line("'t") line number of mark t
line("'" . marker) line number of mark marker
*strftime()*
strftime({format})
The result is a String, which is the current date and time, as
specified by the {format} string. See the manual page of the
C function strftime() for the format. The maximum length of
the result is 80 characters. Examples:
:echo strftime("%c") Sun Apr 27 11:49:23 1997
:echo strftime("%Y %b %d %X") 1997 Apr 27 11:53:25
:echo strftime("%y%m%d %T") 970427 11:53:55
:echo strftime("%H:%M") 11:55
*match()*
match({expr}, {pat})
The result is a Number, which gives the index in {expr} where
{pat} matches. A match at the first character returns zero.
If there is no match -1 is returned. Example:
:echo match("testing", "ing")
results in "4".
See |pattern| for the patterns that are accepted.
*matchend()*
matchend({expr}, {pat})
Same as match(), but return the index of first character after
the match. Example:
:echo matchend("testing", "ing")
results in "7".
*nr2char()*
nr2char({expr})
Return a string with a single chararacter, which has the ASCII
value {expr}. Examples:
nr2char(64) returns "@"
nr2char(32) returns " "
*strlen()*
strlen({expr}) The result is a Number, which is the length of the String
{expr}.
*strpart()*
strpart({src}, {start}, {len})
The result is a String, which is part of {src},
starting from character {start}, with the length {len}.
When non-existing characters are included, this doesn't result
in an error, the characters are simply omitted.
strpart("abcdefg", 3, 2) == "de"
strpart("abcdefg", -2, 4) == "ab"
strpart("abcdefg", 5, 4) == "fg"
Note: To get the first character, {start} must be 0. For
example, to get three characters under and after the cursor:
strpart(getline(line(".")), col(".") - 1, 3)
*synID()*
synID({line}, {col}, {trans})
The result is a Number, which is the syntax ID at the position
{line} and {col} in the current window.
The syntax ID can be used with |synIDattr()| and
|synIDtrans()| to obtain syntax information about text.
{col} is 1 for the leftmost column, {line} is 1 for the first
line.
When {trans} is non-zero, transparant items are reduced to the
item that they reveal. This is useful when wanting to know
the effective color. When {trans} is zero, the transparant
item is returned. This is useful when wanting to know which
syntax item is effective (e.g. inside parens).
Warning: This function can be very slow. Best speed is
obtained by going through the file in forward direction.
Example (echos the name of the syntax item under the cursor):
:echo synIDattr(synID(line("."), col("."), 1), "name")
*synIDattr()*
synIDattr({synID}, {what})
The result is a String, which is the {what} attribute of
syntax ID {synID}. This can be used to obtain information
about a syntax item.
The attributes for the currently active highlighting are used
(GUI, cterm or term).
Use synIDtrans() to follow linked highlight groups.
{what} result
"name" the name of the syntax item
"fg" foreground color (GUI: color name, cterm:
color number as a string, term: empty string)
"bg" background color (like "fg")
"fg#" like "fg", but name in "#RRGGBB" form
"bg#" like "bg", but name in "#RRGGBB" form
"bold" "1" if bold
"italic" "1" if italic
"reverse" "1" if reverse
"inverse" "1" if inverse (= reverse)
"underline" "1" if underlined
Example (echos the color of the syntax item under the cursor):
:echo synIDattr(synIDtrans(synID(line("."), col("."), 1)), "fg")
*synIDtrans()*
synIDtrans({synID})
The result is a Number, which is the translated syntax ID of
{synID}. This is the syntax group ID of what is being used to
highlight the character. Highlight links are followed.
*substitute()*
substitute({expr}, {pat}, {sub}, {flags})
The result is a String, which is a copy of {expr}, in which
the first match of {pat} is replaced with {sub}. This works
like the ":substitute" command (without any flags).
When {pat} does not match in {expr}, {expr} is returned
unmodified.
When {flags} is "g", all matches of {pat} in {expr} are
replaced. Otherwise {flags} should be "".
Example:
:let &path = substitute(&path, ",\\=[^,]*$", "", "")
This removes the last component of the 'path' option.
:echo substitute("testing", ".*", "\\U\\0", "")
results in "TESTING".
*tempname()*
tempname()
The result is a String, which is the name of a file that
doesn't exist. It can be used for a temporary file. The name
is different for each least 26 consecutive calls. Example:
let tmpfile = tempname()
exe "redir > " . tmpfile
*virtcol()*
virtcol({expr})
The result is a Number, which is the screen column of the file
position given with {expr}. That is, the last screen position
occupied by the character at that position, when the screen
would be of unlimited width. When there is a <Tab> at the
position, the returned Number will be the column at the end of
the <Tab>. For example, for a <Tab> in column 1, with 'ts'
set to 8, it returns 8;
The accepted positions are:
. the cursor position
'x position of mark x (if the mark is not set, 0 is
returned)
Note that only marks in the current file can be used.
Examples:
virtcol(".") with text "foo^Lbar", with cursor on the "^L", returns 5
virtcol("'t") with text " there", with 't at 'h', returns 6
The first column is 1. 0 is returned for an error.
*winheight()*
winheight({nr})
The result is a Number, which is the height of window {nr}.
When {nr} is zero, the height of the current window is
returned. When window {nr} doesn't exist, zero is returned.
An existing window always has a height of one or more.
Examples:
echo "The current window has " . winheight(0) . " lines."
*feature-list*
There are two types of features:
1. Features that are only supported when they have been enabled when Vim
was compiled |+feature-list|. Example:
:if has("cindent")
2. Features that are only supported when certain conditions have been met.
Example:
:if has("gui_running")
all_builtin_terms Compiled with all builtin terminals enabled.
amiga Amiga version of Vim.
arp Compiled with ARP support (Amiga).
autocmd Complied with autocommands support.
beos BeOS version of Vim.
builtin_terms Compiled with some builtin terminals.
cindent Compiled with 'cindent' support.
compatible Compiled to be very Vi compatible.
debug Compiled with "DEBUG" defined.
digraphs Compiled with support for digraphs.
dos32 32 bits DOS (DJGPP) version of Vim.
dos16 16 bits DOS version of Vim.
emacs_tags Compiled with support for Emacs tags.
eval Compiled with exression evaluation support. Always
true, of course!
ex_extra Compiled with extra Ex commands |+ex_extra|.
extra_search Compiled with support for |'incsearch'| and
|'hlsearch'|
farsi Compiled with Farsi support |farsi|.
file_in_path Compiled with support for |gf| and |<cfile>|
find_in_path Compiled with support for include file searches
|+find_in_path|.
fname_case Case in file names matters (for Amiga, MS-DOS, and
Windows this is not present).
fork Compiled to use fork()/exec() instead of system().
gui Compiled with GUI enabled.
gui_athena Compiled with Athena GUI.
gui_beos Compiled with BeOs GUI.
gui_mac Compiled with Macintosh GUI.
gui_motif Compiled with Motif GUI.
gui_win32 Compiled with MS Windows Win32 GUI.
gui_win32s idem, and Win32s system being used (Windows 3.1)
gui_running Vim is running in the GUI, or it will start soon.
insert_expand Compiled with support for CTRL-X expansion commands in
Insert mode.
langmap Compiled with 'langmap' support.
lispindent Compiled with support for lisp indenting.
mac Macintosh version of Vim.
mouse Compiled with support mouse.
mouse_dec Compiled with support for Dec terminal mouse.
mouse_netterm Compiled with support for netterm mouse.
mouse_xterm Compiled with support for xterm mouse.
ole Compiled with OLE automation support for Win32.
perl Compiled with Perl interface.
python Compiled with Python interface.
quickfix Compiled with |quickfix| support.
rightleft Compiled with 'rightleft' support.
showcmd Compiled with 'showcmd' support.
smartindent Compiled with 'smartindent' support.
sniff Compiled with SniFF interface support.
syntax Compiled with syntax highlighting support.
syntax_items There are active syntax highlighting items for the
current buffer.
system Compiled to use system() instead of fork()/exec().
tag_binary Compiled with binary searching in tags files
|tag-binary-search|.
tag_old_static Compiled with support for old static tags
|tag-old-static|.
tag_any_white Compiled with support for any white characters in tags
files |tag-any-white|.
terminfo Compiled with terminfo instead of termcap.
textobjects Compiled with support for |text-objects|.
tgetent Compiled with tgetent support, able to use a termcap
or terminfo file.
unix Unix version of Vim.
viminfo Compiled with viminfo support.
win32 Win32 version of Vim (Windows 95/NT)
writebackup Compiled with 'writebackup' default on.
xterm_save Compiled with support for saving and restoring the
xterm screen.
x11 Compiled with X11 support.
5. Commands *expression-commands*
:let {var-name} = {expr1} *:let*
Set internal variable {var-name} to the result of the
expression {expr1}. The variable will get the type
from the {expr}. if {var-name} didn't exist yet, it
is created.
:let ${env-name} = {expr1} *:let-environment* *:let-$*
Set environment variable {env-name} to the result of
the expression {expr1}. The type is always String.
:let @{reg-name} = {expr1} *:let-register* *:let-@*
Write the result of the expression {expr1} in register
{reg-name}. {reg-name} must be a single letter, and
must be the name of a writable register (see
|registers|). "@@" can be used for the unnamed
register. If the result of {expr1} ends in a <CR> or
<NL>, the register will be linewise, otherwise it will
be set to characterwise.
:let &{option-name} = {expr1} *:let-option* *:let-star*
Set option {option-name} to the result of the
expression {expr1}. The type of the option is always
used.
*:unlet* *:unl*
:unl[et] {var-name} Remove the internal variable {var-name}.
:if {expr1} *:if* *:endif* *:en*
:en[dif] Execute the commands until the next matching ":else"
or ":endif" if {expr1} evaluates to non-zero.
From Vim version 4.5 until 5.0, every Ex command in
between the ":if" and ":endif" is ignored. These two
commands were just to allow for future expansions in a
backwards compatible way. Nesting was allowed. Note
that any ":else" or ":elseif" was ignored, the "else"
part was not executed either.
You can use this to remain compatible with older
versions:
:if version >= 500
: version-5-specific-commands
:endif
*:else* *:el*
:else Execute the commands until the next matching ":else"
or ":endif" if they previously were not being
executed.
*:elseif* *:elsei*
:elsei[f] {expr1} Short for ":else" ":if", with the addition that there
is no extra ":endif".
:wh[ile] {expr1} *:while* *:endwhile* *:wh* *:endw*
:endw[hile] Repeat the commands between ":while" and ":endwhile",
as long as {expr1} evaluates to non-zero.
When an error is detected from a command inside the
loop, execution continues after the "endwhile".
NOTE: The ":append" and ":insert" commands don't work properly
inside a ":while" loop.
*:continue* *:con*
:con[tinue] When used inside a ":while", jumps back to the
":while".
*:break* *:brea*
:brea[k] When used inside a ":while", skips to the command
after the matching ":endwhile".
*:ec* *:echo*
:ec[ho] {expr1} .. Echoes each {expr1}, with a space in between and a
terminating <EOL>. Also see |:comment|.
Example:
:echo "the value of 'shell' is" &shell
*:echon*
:echon {expr1} .. Echoes each {expr1}, without anything added. Also see
|:comment|.
Example:
:echon "the value of 'shell' is " &shell
Note the difference between using ":echo", which is a
Vim command, and ":!echo", which is an external shell
command:
:!echo % --> filename
The arguments of ":!" are expanded, see |:_%|.
:!echo "%" --> filename or "filename"
Like the previous example. Whether you see the double
quotes or not depends on your 'shell'.
:echo % --> nothing
The '%' is an illegal character in an expression.
:echo "%" --> %
This just echoes the '%' character.
:echo expand("%") --> filename
This calls the expand() function to expand the '%'.
*:echoh* *:echohl*
:echoh[l] {name} Use the highlight group {name} for the following
":echo[n]" commands. Example:
:echohl WarningMsg | echo "Don't panic!" | echohl None
Don't forget to set the group back to "None",
otherwise all following echo's will be highlighted.
*:exe* *:execute*
:exe[cute] {expr1} .. Executes the string that results from the evaluation
of {expr1} as an Ex command. Multiple arguments are
concatenated, with a space in between. Examples:
:execute "buffer " nextbuf
:execute "normal " count . "w"
Execute can be used to append a next command to
commands that don't accept a '|'. Example:
:execute '!ls' | echo "theend"
Note: The executed string may be any command line, but
you cannot start or end a "while" or "if" command.
Thus this is illegal:
:execute 'while i > 5'
:execute 'echo "test" | break'
It is allowed to have a "while" or "if" command
completely in the executed string:
:execute 'while i < 5 | echo i | let i = i + 1 | endwhile'
*:comment*
":execute", ":echo" and ":echon" cannot be followed by
a comment directly, because they see the '"'' as the
start of a string. But, you can use '|' followed by a
comment. Example:
:echo "foo" | "this is a comment
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