*indent.txt* For Vim version 7.1. Last change: 2007 Aug 17 VIM REFERENCE MANUAL by Bram Moolenaar This file is about indenting C programs and other files. 1. Indenting C programs |C-indenting| 2. Indenting by expression |indent-expression|
1. Indenting C programs *C-indenting* The basics for C indenting are explained in section |30.2| of the user manual. Vim has options for automatically indenting C program files. These options affect only the indent and do not perform other formatting. For comment formatting, see |format-comments|.Notethat this will not work when the |+smartindent| or |+cindent| features have been disabled at compile time. There are in fact four methods available for indentation: '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.Notethat '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 four 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. 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.Notethat 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#,!^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 ":" if you type ':' after a label or case statement "0#" if you type '#' as the first character in a line "!^F" if you typeCTRL-F(which is not inserted) "o" if you type a<CR>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-Fis the default key for this. Be careful if you defineCTRL-Ifor this becauseCTRL-Iis the ASCII code for<Tab>. * When a '*' precedes the key, Vim will reindent the line before inserting the key. If 'cinkeys' contains "*<Return>", 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: "<Up>", "<Ins>" (see |key-notation|). ^ Letters preceded by a caret (^) are control characters. For example: "^F" isCTRL-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<Enter>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 "<o>", "<O>", "<e>", "<0>", "<<>", "<>>", "<*>", "<:>" or "<!>", respectively, for those keys. For an emacs-style indent mode where lines aren't indented every time you press<Enter>but only if you press<Tab>, I suggest: :set cinkeys=0{,0},:,0#,!<Tab>,!^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<BS>,<Tab>, or<Space>in the indent or usedCTRL-TorCTRL-D. *cinoptions-values* The 'cinoptions' option sets how Vim performs indentation. 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. >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=>2sif (cond) if (cond) if (cond){ { {foo; foo; foo;} } }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-2if (cond) { if (cond) { if (cond) {foo; foo; foo;} } }else else else{ { {bar; bar; bar;} } }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-2if (cond) if (cond) if (cond)foo; foo; foo;else else else{ { {bar; bar; bar;} } }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=f1sfunc() func() func(){ { {int foo; int foo; int foo;{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={1sif (cond) if (cond) if (cond){ { {foo; foo; foo;}N Place closing braces N characters from the matching opening brace. (default 0). cino= cino={2,}-0.5s cino=}2if (cond) if (cond) if (cond){ { {foo; foo; foo;} } }^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=^-sfunc() func() func(){ { {if (cond) if (cond) if (cond){ { {a = b; a = b; a = b;} } }} } }:N Place case labels N characters from the indent of the switch(). (default 'shiftwidth'). cino= cino=:0switch (x) switch(x){ {case 1: case 1:a = b; a = b;default: default:} }=N Place statements occurring after a case label N characters from the indent of the label. (default 'shiftwidth'). cino= cino==10case 11: case 11: a = a + 1;a = a + 1; b = b + 1;lN If N != 0 Vim will align with a case label instead of the statement after it in the same line. cino= cino=l1switch (a) { switch (a) {case 1: { case 1: {break; break;} }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). cino= cino=b1switch (x) switch(x){ {case 1: case 1:a = b; a = b;break; break;default: default:a = 0; a = 0;break; break;} }gN Place C++ scope declarations N characters from the indent of the block they are in. (default 'shiftwidth'). A scope declaration can be "public:", "protected:" or "private:". cino= cino=g0{ {public: public:a = b; a = b;private: private:} }hN Place statements occurring after a C++ scope declaration N characters from the indent of the label. (default 'shiftwidth'). cino= cino=h10public: public: a = a + 1;a = a + 1; b = b + 1;pN Parameter declarations for K&R-style function declarations will be indented N characters from the margin. (default 'shiftwidth'). cino= cino=p0 cino=p2sfunc(a, b) func(a, b) func(a, b)int a; int a; int a;char b; char b; char b;tN Indent a function return type declaration N characters from the margin. (default 'shiftwidth'). cino= cino=t0 cino=t7int int intfunc() func() func()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=i0class MyClass : class MyClass :public BaseClass public BaseClass{}{}MyClass::MyClass() : MyClass::MyClass() :BaseClass(3) BaseClass(3)+N Indent a continuation line (a line that spills onto the next) N additional characters. (default 'shiftwidth'). cino= cino=+10{}{}a = b + 9 * a = b + 9 *c; 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.*/ */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:/*") /N Indent comment lines N characters extra. (default 0). cino= cino=/4a = b; a = b;/* comment */ /* comment */c = d; c = d;(N When in unclosed parentheses, indent N characters from the line with the unclosed parentheses. Add a 'shiftwidth' for every unclosed parentheses. When N is 0 or the unclosed parentheses is the first non-white character in its line, line up with the next non-white character after the unclosed parentheses. (default 'shiftwidth' * 2). cino= cino=(0if (c1 && (c2 ||if (c1 && (c2||c3)) c3))foo; foo;if (c1 && if (c1 &&(c2 ||c3)) (c2|| c3)){ {uN Same as (N, but for one level deeper. (default 'shiftwidth'). cino= cino=u2if (c123456789 if (c123456789&& (c22345 && (c22345||UN When N is non-zero, do not ignore the indenting specified by ( or u in case that the unclosed parentheses is the first non-white character in its line. (default 0). cino= or cino=(s cino=(s,U1c3))|| c3))c = c1 && c = c1 &&( (c2 ||c2||c3 c3) && c4; ) && c4;wN When in unclosed parentheses and N is non-zero and either using "(0" or "u0", respectively, or using "U0" and the unclosed parentheses is the first non-white character in its line, line up with the character immediately after the unclosed parentheses rather than the first non-white character. (default 0). cino=(0 cino=(0,w1if ( c1 if ( c1&& ( c2 && ( c2||c3))|| c3))foo; foo;WN When in unclosed parentheses and N is non-zero and either using "(0" or "u0", respectively and the unclosed parentheses is the last non-white character in its line and it is not the closing parentheses, indent the following line N characters relative to the outer context (i.e. start of the line or the next unclosed parentheses). (default: 0). cino=(0 cino=(0,W4a_long_line( a_long_line(argument, argument,argument); argument);a_short_line(argument, a_short_line(argument,argument); argument);mN When N is non-zero, line up a line starting with a closing parentheses with the first character of the line with the matching opening parentheses. (default 0). cino=(s cino=(s,m1c = c1 && ( c = c1 && (c2 ||c2||c3 c3) && c4; ) && c4;if ( if (c1 && c2 c1 && c2) )foo; foo;MN When N is non-zero, line up a line starting with a closing parentheses with the first character of the previous line. (default 0). cino= cino=M1if (cond1 && if (cond1 &&cond2 cond2) )*java-cinoptions* *java-indenting* jN Indent java anonymous classes correctly. 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();}});)N Vim searches for unclosed parentheses at most N lines away. This limits the time needed to search for parentheses. (default 20 lines). *N Vim searches for unclosed comments at most N lines away. This limits the time needed to search for the start of a comment. (default 30 lines). #N When N is non-zero recognize shell/Perl comments, starting with '#'. Default N is zero: don't recognizes '#' comments.Notethat lines starting with # will still be seen as preprocessor lines. The defaults, spelled out in full, are: cinoptions=>s,e0,n0,f0,{0,}0,^0,:s,=s,l0,b0,gs,hs,ps,ts,is,+s,c3,C0, /0,(2s,us,U0,w0,W0,m0,j0,)20,*30,#0 Vim puts a line in column 1 if: - It starts with '#' (preprocessor directives), if 'cinkeys' contains '#'. - It starts with a label (a keyword followed by ':', other than "case" and "default"). - 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 directory for examples.REMARKS ABOUT SPECIFIC INDENT FILESFORTRAN *ft-fortran-indent* Block if, select case, and where constructs are indented. Comments, labelled 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 labelled 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 loopsAll do loops are left unindented by default. Do loops can be unstructured in Fortran with (possibly multiple) loops ending on a labelled executable statement of almost arbitrary type. Correct indentation requires compiler-quality parsing. Old code with do loops ending on labelled statements of arbitrary type can be indented with elaborate programs such as Tidy (http://www.unb.ca/chem/ajit/f_tidy.htm). Structured do/continue loops are also left unindented because continue statements are also 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 followslet fortran_do_enddo=1in 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 asau! BufRead,BufNewFile *.f90 let b:fortran_do_enddo=1to get do loops indented in .f90 files and left alone in Fortran files with other extensions such as .for. PYTHON *ft-python-indent* The amount of indent can be set for the following situations. The examples given are de the defaults.Notethat the variables are set to an expression, so that you can change the value of 'shiftwidth' later. Indent after an open paren:let g:pyindent_open_paren = '&sw * 2'Indent after a nested paren:let g:pyindent_nested_paren = '&sw'Indent for a continuation line:let g:pyindent_continue = '&sw * 2'SHELL *ft-sh-indent* The amount of indent applied under various circumstances in a shell file can be configured by setting the following keys in the |Dictionary| b:sh_indent_defaults to a specific amount or to a |Funcref| that references a function that will return the amount desired: b:sh_indent_options['default'] Default amount of indent. b:sh_indent_options['continuation-line'] Amount of indent to add to a continued line. b:sh_indent_options['case-labels'] Amount of indent to add for case labels. b:sh_indent_options['case-statement'] Amount of indent to add for case statements. b:sh_indent_options['case-breaks'] Amount of indent to add (or more likely remove) for case breaks. VERILOG *ft-verilog-indent* General block statements such as if, for, case, always, initial, function, specify and begin, etc., are indented. The module block statements (first level blocks) are not indented by default. you can turn on the indent with setting a variable in the .vimrc as follows:let b:verilog_indent_modules = 1then the module blocks will be indented. To stop this, remove the variable::unlet b:verilog_indent_modulesTo set the variable only for Verilog file. The following statements can be used:au BufReadPost * if exists("b:current_syntax")au BufReadPost * if b:current_syntax == "verilog"au BufReadPost * let b:verilog_indent_modules = 1au BufReadPost * endifau BufReadPost * endifFurthermore, setting the variable b:verilog_indent_width to change the indenting width (default is 'shiftwidth'):let b:verilog_indent_width = 4let b:verilog_indent_width = &sw * 2In addition, you can turn the verbose mode for debug issue:let b:verilog_indent_verbose = 1Make sure to do ":set cmdheight=2" first to allow the display of the message. VHDL *ft-vhdl-indent* Alignment of generic/port mapping statements are performed by default. This causes the following alignment example:ENTITY sync ISPORT (clk : IN STD_LOGIC;reset_n : IN STD_LOGIC;data_input : IN STD_LOGIC;data_out : OUT STD_LOGIC);END ENTITY sync;To turn this off, addlet g:vhdl_indent_genportmap = 0to the .vimrc file, which causes the previous alignment example to change:ENTITY sync ISPORT (clk : IN STD_LOGIC;reset_n : IN STD_LOGIC;data_input : IN STD_LOGIC;data_out : OUT STD_LOGIC);END ENTITY sync;
Alignment of right-hand side assignment "<=" statements are performed by default. This causes the following alignment example:sig_out <= (bus_a(1) AND(sig_b OR sig_c)) OR(bus_a(0) AND sig_d);To turn this off, addlet g:vhdl_indent_rhsassign = 0to the .vimrc file, which causes the previous alignment example to change:sig_out <= (bus_a(1) AND(sig_b OR sig_c)) OR(bus_a(0) AND sig_d);
Full-line comments (lines that begin with "--") are indented to be aligned with the very previous line's comment, PROVIDED that a whitespace follows after "--". For example:sig_a <= sig_b; -- start of a comment-- continuation of the comment-- more of the same commentWhile in Insert mode, after typing "-- " (notethe space " "), hittingCTRL-Fwill align the current "-- " with the previous line's "--". If the very previous line does not contain "--", THEN the full-line comment will be aligned with the start of the next non-blank line that is NOT a full-line comment. Indenting the following code:sig_c <= sig_d; -- comment 0-- comment 1-- comment 2--debug_code:--PROCESS(debug_in)--BEGIN-- FOR i IN 15 DOWNTO 0 LOOP-- debug_out(8*i+7 DOWNTO 8*i) <= debug_in(15-i);-- END LOOP;--END PROCESS debug_code;-- comment 3sig_e <= sig_f; -- comment 4-- comment 5results in:sig_c <= sig_d; -- comment 0-- comment 1-- comment 2--debug_code:--PROCESS(debug_in)--BEGIN-- FOR i IN 15 DOWNTO 0 LOOP-- debug_out(8*i+7 DOWNTO 8*i) <= debug_in(15-i);-- END LOOP;--END PROCESS debug_code;-- comment 3sig_e <= sig_f; -- comment 4-- comment 5Notice that "--debug_code:" does not align with "-- comment 2" because there is no whitespace that follows after "--" in "--debug_code:". Given the dynamic nature of indenting comments, indenting should be done TWICE. On the first pass, code will be indented. On the second pass, full-line comments will be indented according to the correctly indented code. VIM *ft-vim-indent* For indenting Vim scripts there is one variable that specifies the amount of indent for a continuation line, a line that starts with a backslash::let g:vim_indent_cont = &sw * 3Three times shiftwidth is the default value. vim:tw=78:ts=8:ft=help:norl:
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