Edit: /usr/share/vim/vim91/doc/indent.txt (43699B)
*indent.txt* For Vim version 9.1. Last change: 2023 Dec 27
VIM REFERENCE MANUAL by Bram Moolenaar
This file is about indenting C programs and other files.
1. Indenting C style programs |C-indenting|
2. Indenting by expression |indent-expression|
==============================================================================
1. Indenting C style programs *C-indenting*
The basics for C style indenting are explained in section |30.2| of the user
manual.
Vim has options for automatically indenting C style program files. Many
programming languages including Java and C++ follow very closely the
formatting conventions established with C. These options affect only the
indent and do not perform other formatting. There are additional options that
affect other kinds of formatting as well as indenting, see |format-comments|,
|fo-table|, |gq| and |formatting| for the main ones.
There are in fact four main methods available for indentation, each one
overrides the previous if it is enabled, or non-empty for 'indentexpr':
'autoindent' uses the indent from the previous line.
'smartindent' is like 'autoindent' but also recognizes some C syntax to
increase/reduce the indent where appropriate.
'cindent' Works more cleverly than the other two and is configurable to
different indenting styles.
'indentexpr' The most flexible of all: Evaluates an expression to compute
the indent of a line. When non-empty this method overrides
the other ones. See |indent-expression|.
The rest of this section describes the 'cindent' option.
Note that 'cindent' indenting does not work for every code scenario. Vim
is not a C compiler: it does not recognize all syntax. One requirement is
that toplevel functions have a '{' in the first column. Otherwise they are
easily confused with declarations.
These five options control C program indenting:
'cindent' Enables Vim to perform C program indenting automatically.
'cinkeys' Specifies which keys trigger reindenting in insert mode.
'cinoptions' Sets your preferred indent style.
'cinwords' Defines keywords that start an extra indent in the next line.
'cinscopedecls' Defines strings that are recognized as a C++ scope declaration.
If 'lisp' is not on and 'equalprg' is empty, the "=" operator indents using
Vim's built-in algorithm rather than calling an external program.
See |autocommand| for how to set the 'cindent' option automatically for C code
files and reset it for others.
*cinkeys-format* *indentkeys-format*
The 'cinkeys' option is a string that controls Vim's indenting in response to
typing certain characters or commands in certain contexts. Note that this not
only triggers C-indenting. When 'indentexpr' is not empty 'indentkeys' is
used instead. The format of 'cinkeys' and 'indentkeys' is equal.
The default is "0{,0},0),0],:,0#,!^F,o,O,e" which specifies that indenting
occurs as follows:
"0{" if you type '{' as the first character in a line
"0}" if you type '}' as the first character in a line
"0)" if you type ')' as the first character in a line
"0]" if you type ']' as the first character in a line
":" if you type ':' after a label or case statement
"0#" if you type '#' as the first character in a line
"!^F" if you type CTRL-F (which is not inserted)
"o" if you type a
anywhere or use the "o" command (not in
insert mode!)
"O" if you use the "O" command (not in insert mode!)
"e" if you type the second 'e' for an "else" at the start of a
line
Characters that can precede each key: *i_CTRL-F*
! When a '!' precedes the key, Vim will not insert the key but will
instead reindent the current line. This allows you to define a
command key for reindenting the current line. CTRL-F is the default
key for this. Be careful if you define CTRL-I for this because CTRL-I
is the ASCII code for .
* When a '*' precedes the key, Vim will reindent the line before
inserting the key. If 'cinkeys' contains "*", Vim reindents
the current line before opening a new line.
0 When a zero precedes the key (but appears after '!' or '*') Vim will
reindent the line only if the key is the first character you type in
the line. When used before "=" Vim will only reindent the line if
there is only white space before the word.
When neither '!' nor '*' precedes the key, Vim reindents the line after you
type the key. So ';' sets the indentation of a line which includes the ';'.
Special key names:
<> Angle brackets mean spelled-out names of keys. For example: "",
"" (see |key-notation|).
^ Letters preceded by a caret (^) are control characters. For example:
"^F" is CTRL-F.
o Reindent a line when you use the "o" command or when Vim opens a new
line below the current one (e.g., when you type in insert
mode).
O Reindent a line when you use the "O" command.
e Reindent a line that starts with "else" when you type the second 'e'.
: Reindent a line when a ':' is typed which is after a label or case
statement. Don't reindent for a ":" in "class::method" for C++. To
Reindent for any ":", use "<:>".
=word Reindent when typing the last character of "word". "word" may
actually be part of another word. Thus "=end" would cause reindenting
when typing the "d" in "endif" or "endwhile". But not when typing
"bend". Also reindent when completion produces a word that starts
with "word". "0=word" reindents when there is only white space before
the word.
=~word Like =word, but ignore case.
If you really want to reindent when you type 'o', 'O', 'e', '0', '<', '>',
'*', ':' or '!', use "", "", "", "<0>", "<<>", "<>>", "<*>", "<:>" or
"", respectively, for those keys.
For an emacs-style indent mode where lines aren't indented every time you
press but only if you press , I suggest:
:set cinkeys=0{,0},:,0#,!,!^F
You might also want to switch off 'autoindent' then.
Note: If you change the current line's indentation manually, Vim ignores the
cindent settings for that line. This prevents vim from reindenting after you
have changed the indent by typing , , or in the indent or
used CTRL-T or CTRL-D.
*cinoptions-values*
The 'cinoptions' option sets how Vim performs indentation. The value after
the option character can be one of these (N is any number):
N indent N spaces
-N indent N spaces to the left
Ns N times 'shiftwidth' spaces
-Ns N times 'shiftwidth' spaces to the left
In the list below,
"N" represents a number of your choice (the number can be negative). When
there is an 's' after the number, Vim multiplies the number by 'shiftwidth':
"1s" is 'shiftwidth', "2s" is two times 'shiftwidth', etc. You can use a
decimal point, too: "-0.5s" is minus half a 'shiftwidth'.
The examples below assume a 'shiftwidth' of 4.
*cino->*
>N Amount added for "normal" indent. Used after a line that should
increase the indent (lines starting with "if", an opening brace,
etc.). (default 'shiftwidth').
cino= cino=>2 cino=>2s >
if (cond) if (cond) if (cond)
{ { {
foo; foo; foo;
} } }
<
*cino-e*
eN Add N to the prevailing indent inside a set of braces if the
opening brace at the End of the line (more precise: is not the
first character in a line). This is useful if you want a
different indent when the '{' is at the start of the line from
when '{' is at the end of the line. (default 0).
cino= cino=e2 cino=e-2 >
if (cond) { if (cond) { if (cond) {
foo; foo; foo;
} } }
else else else
{ { {
bar; bar; bar;
} } }
<
*cino-n*
nN Add N to the prevailing indent for a statement after an "if",
"while", etc., if it is NOT inside a set of braces. This is
useful if you want a different indent when there is no '{'
before the statement from when there is a '{' before it.
(default 0).
cino= cino=n2 cino=n-2 >
if (cond) if (cond) if (cond)
foo; foo; foo;
else else else
{ { {
bar; bar; bar;
} } }
<
*cino-f*
fN Place the first opening brace of a function or other block in
column N. This applies only for an opening brace that is not
inside other braces and is at the start of the line. What comes
after the brace is put relative to this brace. (default 0).
cino= cino=f.5s cino=f1s >
func() func() func()
{ { {
int foo; int foo; int foo;
<
*cino-{*
{N Place opening braces N characters from the prevailing indent.
This applies only for opening braces that are inside other
braces. (default 0).
cino= cino={.5s cino={1s >
if (cond) if (cond) if (cond)
{ { {
foo; foo; foo;
<
*cino-}*
}N Place closing braces N characters from the matching opening
brace. (default 0).
cino= cino={2,}-0.5s cino=}2 >
if (cond) if (cond) if (cond)
{ { {
foo; foo; foo;
} } }
<
*cino-^*
^N Add N to the prevailing indent inside a set of braces if the
opening brace is in column 0. This can specify a different
indent for whole of a function (some may like to set it to a
negative number). (default 0).
cino= cino=^-2 cino=^-s >
func() func() func()
{ { {
if (cond) if (cond) if (cond)
{ { {
a = b; a = b; a = b;
} } }
} } }
<
*cino-L*
LN Controls placement of jump labels. If N is negative, the label
will be placed at column 1. If N is non-negative, the indent of
the label will be the prevailing indent minus N. (default -1).
cino= cino=L2 cino=Ls >
func() func() func()
{ { {
{ { {
stmt; stmt; stmt;
LABEL: LABEL: LABEL:
} } }
} } }
<
*cino-:*
:N Place case labels N characters from the indent of the switch().
(default 'shiftwidth').
cino= cino=:0 >
switch (x) switch(x)
{ {
case 1: case 1:
a = b; a = b;
default: default:
} }
<
*cino-=*
=N Place statements occurring after a case label N characters from
the indent of the label. (default 'shiftwidth').
cino= cino==10 >
case 11: case 11: a = a + 1;
a = a + 1; b = b + 1;
<
*cino-l*
lN If N != 0 Vim will align with a case label instead of the
statement after it in the same line.
cino= cino=l1 >
switch (a) { switch (a) {
case 1: { case 1: {
break; break;
} }
<
*cino-b*
bN If N != 0 Vim will align a final "break" with the case label,
so that case..break looks like a sort of block. (default: 0).
When using 1, consider adding "0=break" to 'cinkeys'.
cino= cino=b1 >
switch (x) switch(x)
{ {
case 1: case 1:
a = b; a = b;
break; break;
default: default:
a = 0; a = 0;
break; break;
} }
<
*cino-g*
gN Place C++ scope declarations N characters from the indent of the
block they are in. (default 'shiftwidth'). By default, a scope
declaration is "public:", "protected:" or "private:". This can
be adjusted with the 'cinscopedecls' option.
cino= cino=g0 >
{ {
public: public:
a = b; a = b;
private: private:
} }
<
*cino-h*
hN Place statements occurring after a C++ scope declaration N
characters from the indent of the label. (default
'shiftwidth').
cino= cino=h10 >
public: public: a = a + 1;
a = a + 1; b = b + 1;
<
*cino-N*
NN Indent inside C++ namespace N characters extra compared to a
normal block. (default 0).
cino= cino=N-s >
namespace { namespace {
void function(); void function();
} }
namespace my namespace my
{ {
void function(); void function();
} }
<
*cino-E*
EN Indent inside C++ linkage specifications (extern "C" or
extern "C++") N characters extra compared to a normal block.
(default 0).
cino= cino=E-s >
extern "C" { extern "C" {
void function(); void function();
} }
extern "C" extern "C"
{ {
void function(); void function();
} }
<
*cino-p*
pN Parameter declarations for K&R-style function declarations will
be indented N characters from the margin. (default
'shiftwidth').
cino= cino=p0 cino=p2s >
func(a, b) func(a, b) func(a, b)
int a; int a; int a;
char b; char b; char b;
<
*cino-t*
tN Indent a function return type declaration N characters from the
margin. (default 'shiftwidth').
cino= cino=t0 cino=t7 >
int int int
func() func() func()
<
*cino-i*
iN Indent C++ base class declarations and constructor
initializations, if they start in a new line (otherwise they
are aligned at the right side of the ':').
(default 'shiftwidth').
cino= cino=i0 >
class MyClass : class MyClass :
public BaseClass public BaseClass
{} {}
MyClass::MyClass() : MyClass::MyClass() :
BaseClass(3) BaseClass(3)
{} {}
<
*cino-+*
+N Indent a continuation line (a line that spills onto the next)
inside a function N additional characters. (default
'shiftwidth').
Outside of a function, when the previous line ended in a
backslash, the 2 * N is used.
cino= cino=+10 >
a = b + 9 * a = b + 9 *
c; c;
<
*cino-c*
cN Indent comment lines after the comment opener, when there is no
other text with which to align, N characters from the comment
opener. (default 3). See also |format-comments|.
cino= cino=c5 >
/* /*
text. text.
*/ */
<
*cino-C*
CN When N is non-zero, indent comment lines by the amount specified
with the c flag above even if there is other text behind the
comment opener. (default 0).
cino=c0 cino=c0,C1 >
/******** /********
text. text.
********/ ********/
< (Example uses ":set comments& comments-=s1:/* comments^=s0:/*")
*cino-/*
/N Indent comment lines N characters extra. (default 0).
cino= cino=/4 >
a = b; a = b;
/* comment */ /* comment */
c = d; c = d;
<
*cino-(*
(N When in unclosed parentheses, indent N characters from the line
with the unclosed parenthesis. Add a 'shiftwidth' for every
extra unclosed parentheses. When N is 0 or the unclosed
parenthesis is the first non-white character in its line, line
up with the next non-white character after the unclosed
parenthesis. (default 'shiftwidth' * 2).
cino= cino=(0 >
if (c1 && (c2 || if (c1 && (c2 ||
c3)) c3))
foo; foo;
if (c1 && if (c1 &&
(c2 || c3)) (c2 || c3))
{ {
<
*cino-u*
uN Same as (N, but for one nesting level deeper.
(default 'shiftwidth').
cino= cino=u2 >
if (c123456789 if (c123456789
&& (c22345 && (c22345
|| c3)) || c3))
<
*cino-U*
UN When N is non-zero, do not ignore the indenting specified by
( or u in case that the unclosed parenthesis is the first
non-white character in its line. (default 0).
cino= or cino=(s cino=(s,U1 >
c = c1 && c = c1 &&
( (
c2 || c2 ||
c3 c3
) && c4; ) && c4;
<
*cino-w*
wN When in unclosed parentheses and N is non-zero and either
using "(0" or "u0", respectively, or using "U0" and the unclosed
parenthesis is the first non-white character in its line, line
up with the character immediately after the unclosed parenthesis
rather than the first non-white character. (default 0).
cino=(0 cino=(0,w1 >
if ( c1 if ( c1
&& ( c2 && ( c2
|| c3)) || c3))
foo; foo;
<
*cino-W*
WN When in unclosed parentheses and N is non-zero and either
using "(0" or "u0", respectively and the unclosed parenthesis is
the last non-white character in its line and it is not the
closing parenthesis, indent the following line N characters
relative to the outer context (i.e. start of the line or the
next unclosed parenthesis). (default: 0).
cino=(0 cino=(0,W4 >
a_long_line( a_long_line(
argument, argument,
argument); argument);
a_short_line(argument, a_short_line(argument,
argument); argument);
<
*cino-k*
kN When in unclosed parentheses which follow "if", "for" or
"while" and N is non-zero, overrides the behaviour defined by
"(N": causes the indent to be N characters relative to the outer
context (i.e. the line where "if", "for" or "while" is). Has
no effect on deeper levels of nesting. Affects flags like "wN"
only for the "if", "for" and "while" conditions. If 0, defaults
to behaviour defined by the "(N" flag. (default: 0).
cino=(0 cino=(0,ks >
if (condition1 if (condition1
&& condition2) && condition2)
action(); action();
function(argument1 function(argument1
&& argument2); && argument2);
<
*cino-m*
mN When N is non-zero, line up a line starting with a closing
parenthesis with the first character of the line with the
matching opening parenthesis. (default 0).
cino=(s cino=(s,m1 >
c = c1 && ( c = c1 && (
c2 || c2 ||
c3 c3
) && c4; ) && c4;
if ( if (
c1 && c2 c1 && c2
) )
foo; foo;
<
*cino-M*
MN When N is non-zero, line up a line starting with a closing
parenthesis with the first character of the previous line.
(default 0).
cino= cino=M1 >
if (cond1 && if (cond1 &&
cond2 cond2
) )
<
*java-cinoptions* *java-indenting* *cino-j*
jN Indent Java anonymous classes correctly. Also works well for
Javascript. The value 'N' is currently unused but must be
non-zero (e.g. 'j1'). 'j1' will indent for example the
following code snippet correctly: >
object.add(new ChangeListener() {
public void stateChanged(ChangeEvent e) {
do_something();
}
});
<
*javascript-cinoptions* *javascript-indenting* *cino-J*
JN Indent JavaScript object declarations correctly by not confusing
them with labels. The value 'N' is currently unused but must be
non-zero (e.g. 'J1'). If you enable this you probably also want
to set |cino-j|. >
var bar = {
foo: {
that: this,
some: ok,
},
"bar":{
a : 2,
b: "123abc",
x: 4,
"y": 5
}
}
<
*cino-)*
)N Vim searches for unclosed parentheses at most N lines away.
This limits the time needed to search for parentheses. (default
20 lines).
*cino-star*
*N Vim searches for unclosed comments at most N lines away. This
limits the time needed to search for the start of a comment.
If your /* */ comments stop indenting after N lines this is the
value you will want to change.
(default 70 lines).
*cino-#*
#N When N is non-zero recognize shell/Perl comments starting with
'#', do not recognize preprocessor lines; allow right-shifting
lines that start with "#".
When N is zero (default): don't recognize '#' comments, do
recognize preprocessor lines; right-shifting lines that start
with "#" does not work.
*cino-P*
PN When N is non-zero recognize C pragmas, and indent them like any
other code; does not concern other preprocessor directives.
When N is zero (default): don't recognize C pragmas, treating
them like every other preprocessor directive.
The defaults, spelled out in full, are:
cinoptions=>s,e0,n0,f0,{0,}0,^0,L-1,:s,=s,l0,b0,gs,hs,N0,E0,ps,ts,is,+s,
c3,C0,/0,(2s,us,U0,w0,W0,k0,m0,j0,J0,)20,*70,#0,P0
Vim puts a line in column 1 if:
- It starts with '#' (preprocessor directives), if 'cinkeys' contains '#0'.
- It starts with a label (a keyword followed by ':', other than "case" and
"default") and 'cinoptions' does not contain an 'L' entry with a positive
value.
- Any combination of indentations causes the line to have less than 0
indentation.
==============================================================================
2. Indenting by expression *indent-expression*
The basics for using flexible indenting are explained in section |30.3| of the
user manual.
If you want to write your own indent file, it must set the 'indentexpr'
option. Setting the 'indentkeys' option is often useful.
See the $VIMRUNTIME/indent/README.txt file for hints.
See the $VIMRUNTIME/indent directory for examples.
REMARKS ABOUT SPECIFIC INDENT FILES ~
CLOJURE *ft-clojure-indent* *clojure-indent*
Clojure indentation differs somewhat from traditional Lisps, due in part to
the use of square and curly brackets, and otherwise by community convention.
These conventions are not universally followed, so the Clojure indent script
offers a few configuration options.
(If the current Vim does not include |searchpairpos()|, the indent script falls
back to normal 'lisp' indenting, and the following options are ignored.)
*g:clojure_maxlines*
Sets maximum scan distance of `searchpairpos()`. Larger values trade
performance for correctness when dealing with very long forms. A value of
0 will scan without limits. The default is 300.
*g:clojure_fuzzy_indent*
*g:clojure_fuzzy_indent_patterns*
*g:clojure_fuzzy_indent_blacklist*
The 'lispwords' option is a list of comma-separated words that mark special
forms whose subforms should be indented with two spaces.
For example:
>
(defn bad []
"Incorrect indentation")
(defn good []
"Correct indentation")
<
If you would like to specify 'lispwords' with a |pattern| instead, you can use
the fuzzy indent feature:
>
" Default
let g:clojure_fuzzy_indent = 1
let g:clojure_fuzzy_indent_patterns = ['^with', '^def', '^let']
let g:clojure_fuzzy_indent_blacklist =
\ ['-fn$', '\v^with-%(meta|out-str|loading-context)$']
<
|g:clojure_fuzzy_indent_patterns| and |g:clojure_fuzzy_indent_blacklist| are
lists of patterns that will be matched against the unqualified symbol at the
head of a list. This means that a pattern like `"^foo"` will match all these
candidates: `foobar`, `my.ns/foobar`, and `#'foobar`.
Each candidate word is tested for special treatment in this order:
1. Return true if word is literally in 'lispwords'
2. Return false if word matches a pattern in
|g:clojure_fuzzy_indent_blacklist|
3. Return true if word matches a pattern in
|g:clojure_fuzzy_indent_patterns|
4. Return false and indent normally otherwise
*g:clojure_special_indent_words*
Some forms in Clojure are indented such that every subform is indented by only
two spaces, regardless of 'lispwords'. If you have a custom construct that
should be indented in this idiosyncratic fashion, you can add your symbols to
the default list below.
>
" Default
let g:clojure_special_indent_words =
\ 'deftype,defrecord,reify,proxy,extend-type,extend-protocol,letfn'
<
*g:clojure_align_multiline_strings*
Align subsequent lines in multi-line strings to the column after the opening
quote, instead of the same column.
For example:
>
(def default
"Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do
eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut
enim ad minim veniam, quis nostrud exercitation ullamco laboris
nisi ut aliquip ex ea commodo consequat.")
(def aligned
"Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do
eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut
enim ad minim veniam, quis nostrud exercitation ullamco laboris
nisi ut aliquip ex ea commodo consequat.")
<
*g:clojure_align_subforms*
By default, parenthesized compound forms that look like function calls and
whose head subform is on its own line have subsequent subforms indented by
two spaces relative to the opening paren:
>
(foo
bar
baz)
<
Setting this option to `1` changes this behaviour so that all subforms are
aligned to the same column, emulating the default behaviour of
clojure-mode.el:
>
(foo
bar
baz)
<
FORTRAN *ft-fortran-indent*
Block if, select case, select type, select rank, where, forall, type,
interface, associate, block, enum, critical, and change team constructs are
indented. The indenting of subroutines, functions, modules, and program blocks
is optional. Comments, labeled statements, and continuation lines are indented
if the Fortran is in free source form, whereas they are not indented if the
Fortran is in fixed source form because of the left margin requirements. Hence
manual indent corrections will be necessary for labeled statements and
continuation lines when fixed source form is being used. For further
discussion of the method used for the detection of source format see
|ft-fortran-syntax|.
Do loops ~
All do loops are left unindented by default. Do loops can be unstructured in
Fortran with (possibly multiple) loops ending on a labeled executable
statement of almost arbitrary type. Correct indentation requires
compiler-quality parsing. Old code with do loops ending on labeled statements
of arbitrary type can be indented with elaborate programs such as Tidy.
Structured do/continue loops are also left unindented because continue
statements are used for purposes other than ending a do loop. Programs such
as Tidy can convert structured do/continue loops to the do/enddo form. Do
loops of the do/enddo variety can be indented. If you use only structured
loops of the do/enddo form, you should declare this by setting the
fortran_do_enddo variable in your .vimrc as follows >
let fortran_do_enddo=1
in which case do loops will be indented. If all your loops are of do/enddo
type only in, say, .f90 files, then you should set a buffer flag with an
autocommand such as >
au! BufRead,BufNewFile *.f90 let b:fortran_do_enddo=1
to get do loops indented in .f90 files and left alone in Fortran files with
other extensions such as .for.
Program units ~
Indenting of program units (subroutines, functions, modules, and program
blocks) can be increased by setting the variable fortran_indent_more and can
be decreased by setting the variable fortran_indent_less. These variables
can be set for all fortran files in your .vimrc as follows >
let fortran_indent_less=1
A finer level of control can be achieved by setting the corresponding
buffer-local variable as follows >
let b:fortran_indent_less=1
HTML *ft-html-indent* *html-indent* *html-indenting*
This is about variables you can set in your vimrc to customize HTML indenting.
You can set the indent for the first line after