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diff --git a/runtime/doc/usr_30.txt b/runtime/doc/usr_30.txt new file mode 100644 index 0000000..79fcf7b --- /dev/null +++ b/runtime/doc/usr_30.txt @@ -0,0 +1,643 @@ +*usr_30.txt* For Vim version 8.1. Last change: 2007 Nov 10 + + VIM USER MANUAL - by Bram Moolenaar + + Editing programs + + +Vim has various commands that aid in writing computer programs. Compile a +program and directly jump to reported errors. Automatically set the indent +for many languages and format comments. + +|30.1| Compiling +|30.2| Indenting C files +|30.3| Automatic indenting +|30.4| Other indenting +|30.5| Tabs and spaces +|30.6| Formatting comments + + Next chapter: |usr_31.txt| Exploiting the GUI + Previous chapter: |usr_29.txt| Moving through programs +Table of contents: |usr_toc.txt| + +============================================================================== +*30.1* Compiling + +Vim has a set of so called "quickfix" commands. They enable you to compile a +program from within Vim and then go through the errors generated and fix them +(hopefully). You can then recompile and fix any new errors that are found +until finally your program compiles without any error. + +The following command runs the program "make" (supplying it with any argument +you give) and captures the results: > + + :make {arguments} + +If errors were generated, they are captured and the editor positions you where +the first error occurred. + Take a look at an example ":make" session. (Typical :make sessions generate +far more errors and fewer stupid ones.) After typing ":make" the screen looks +like this: + + :!make | &tee /tmp/vim215953.err ~ + gcc -g -Wall -o prog main.c sub.c ~ + main.c: In function 'main': ~ + main.c:6: too many arguments to function 'do_sub' ~ + main.c: At top level: ~ + main.c:10: parse error before '}' ~ + make: *** [prog] Error 1 ~ + + 2 returned ~ + "main.c" 11L, 111C ~ + (3 of 6): too many arguments to function 'do_sub' ~ + Press ENTER or type command to continue ~ + +From this you can see that you have errors in the file "main.c". When you +press <Enter>, Vim displays the file "main.c", with the cursor positioned on +line 6, the first line with an error. You did not need to specify the file or +the line number, Vim knew where to go by looking in the error messages. + + +---------------------------------------------------+ + |int main() | + |{ | + | int i=3; | + cursor -> | do_sub("foo"); | + | ++i; | + | return (0); | + |} | + |} | + | ~ | + |(3 of 12): too many arguments to function 'do_sub' | + +---------------------------------------------------+ + +The following command goes to where the next error occurs: > + + :cnext + +Vim jumps to line 10, the last line in the file, where there is an extra '}'. + When there is not enough room, Vim will shorten the error message. To see +the whole message use: > + + :cc + +You can get an overview of all the error messages with the ":clist" command. +The output looks like this: > + + :clist +< 3 main.c: 6:too many arguments to function 'do_sub' ~ + 5 main.c: 10:parse error before '}' ~ + +Only the lines where Vim recognized a file name and line number are listed +here. It assumes those are the interesting lines and the rest is just boring +messages. However, sometimes unrecognized lines do contain something you want +to see. Output from the linker, for example, about an undefined function. +To see all the messages add a "!" to the command: > + + :clist! +< 1 gcc -g -Wall -o prog main.c sub.c ~ + 2 main.c: In function 'main': ~ + 3 main.c:6: too many arguments to function 'do_sub' ~ + 4 main.c: At top level: ~ + 5 main.c:10: parse error before '}' ~ + 6 make: *** [prog] Error 1 ~ + +Vim will highlight the current error. To go back to the previous error, use: +> + :cprevious + +Other commands to move around in the error list: + + :cfirst to first error + :clast to last error + :cc 3 to error nr 3 + + +USING ANOTHER COMPILER + +The name of the program to run when the ":make" command is executed is defined +by the 'makeprg' option. Usually this is set to "make", but Visual C++ users +should set this to "nmake" by executing the following command: > + + :set makeprg=nmake + +You can also include arguments in this option. Special characters need to +be escaped with a backslash. Example: > + + :set makeprg=nmake\ -f\ project.mak + +You can include special Vim keywords in the command specification. The % +character expands to the name of the current file. So if you execute the +command: > + :set makeprg=make\ %:S + +When you are editing main.c, then ":make" executes the following command: > + + make main.c + +This is not too useful, so you will refine the command a little and use the :r +(root) modifier: > + + :set makeprg=make\ %:r:S.o + +Now the command executed is as follows: > + + make main.o + +More about these modifiers here: |filename-modifiers|. + + +OLD ERROR LISTS + +Suppose you ":make" a program. There is a warning message in one file and an +error message in another. You fix the error and use ":make" again to check if +it was really fixed. Now you want to look at the warning message. It doesn't +show up in the last error list, since the file with the warning wasn't +compiled again. You can go back to the previous error list with: > + + :colder + +Then use ":clist" and ":cc {nr}" to jump to the place with the warning. + To go forward to the next error list: > + + :cnewer + +Vim remembers ten error lists. + + +SWITCHING COMPILERS + +You have to tell Vim what format the error messages are that your compiler +produces. This is done with the 'errorformat' option. The syntax of this +option is quite complicated and it can be made to fit almost any compiler. +You can find the explanation here: |errorformat|. + +You might be using various different compilers. Setting the 'makeprg' option, +and especially the 'errorformat' each time is not easy. Vim offers a simple +method for this. For example, to switch to using the Microsoft Visual C++ +compiler: > + + :compiler msvc + +This will find the Vim script for the "msvc" compiler and set the appropriate +options. + You can write your own compiler files. See |write-compiler-plugin|. + + +OUTPUT REDIRECTION + +The ":make" command redirects the output of the executed program to an error +file. How this works depends on various things, such as the 'shell'. If your +":make" command doesn't capture the output, check the 'makeef' and +'shellpipe' options. The 'shellquote' and 'shellxquote' options might also +matter. + +In case you can't get ":make" to redirect the file for you, an alternative is +to compile the program in another window and redirect the output into a file. +Then have Vim read this file with: > + + :cfile {filename} + +Jumping to errors will work like with the ":make" command. + +============================================================================== +*30.2* Indenting C style text + +A program is much easier to understand when the lines have been properly +indented. Vim offers various ways to make this less work. For C or C style +programs like Java or C++, set the 'cindent' option. Vim knows a lot about C +programs and will try very hard to automatically set the indent for you. Set +the 'shiftwidth' option to the amount of spaces you want for a deeper level. +Four spaces will work fine. One ":set" command will do it: > + + :set cindent shiftwidth=4 + +With this option enabled, when you type something such as "if (x)", the next +line will automatically be indented an additional level. + + if (flag) + Automatic indent ---> do_the_work(); + Automatic unindent <-- if (other_flag) { + Automatic indent ---> do_file(); + keep indent do_some_more(); + Automatic unindent <-- } + +When you type something in curly braces ({}), the text will be indented at the +start and unindented at the end. The unindenting will happen after typing the +'}', since Vim can't guess what you are going to type. + +One side effect of automatic indentation is that it helps you catch errors in +your code early. When you type a } to finish a function, only to find that +the automatic indentation gives it more indent than what you expected, there +is probably a } missing. Use the "%" command to find out which { matches the +} you typed. + A missing ) and ; also cause extra indent. Thus if you get more white +space than you would expect, check the preceding lines. + +When you have code that is badly formatted, or you inserted and deleted lines, +you need to re-indent the lines. The "=" operator does this. The simplest +form is: > + + == + +This indents the current line. Like with all operators, there are three ways +to use it. In Visual mode "=" indents the selected lines. A useful text +object is "a{". This selects the current {} block. Thus, to re-indent the +code block the cursor is in: > + + =a{ + +I you have really badly indented code, you can re-indent the whole file with: +> + gg=G + +However, don't do this in files that have been carefully indented manually. +The automatic indenting does a good job, but in some situations you might want +to overrule it. + + +SETTING INDENT STYLE + +Different people have different styles of indentation. By default Vim does a +pretty good job of indenting in a way that 90% of programmers do. There are +different styles, however; so if you want to, you can customize the +indentation style with the 'cinoptions' option. + By default 'cinoptions' is empty and Vim uses the default style. You can +add various items where you want something different. For example, to make +curly braces be placed like this: + + if (flag) ~ + { ~ + i = 8; ~ + j = 0; ~ + } ~ + +Use this command: > + + :set cinoptions+={2 + +There are many of these items. See |cinoptions-values|. + +============================================================================== +*30.3* Automatic indenting + +You don't want to switch on the 'cindent' option manually every time you edit +a C file. This is how you make it work automatically: > + + :filetype indent on + +Actually, this does a lot more than switching on 'cindent' for C files. First +of all, it enables detecting the type of a file. That's the same as what is +used for syntax highlighting. + When the filetype is known, Vim will search for an indent file for this +type of file. The Vim distribution includes a number of these for various +programming languages. This indent file will then prepare for automatic +indenting specifically for this file. + +If you don't like the automatic indenting, you can switch it off again: > + + :filetype indent off + +If you don't like the indenting for one specific type of file, this is how you +avoid it. Create a file with just this one line: > + + :let b:did_indent = 1 + +Now you need to write this in a file with a specific name: + + {directory}/indent/{filetype}.vim + +The {filetype} is the name of the file type, such as "cpp" or "java". You can +see the exact name that Vim detected with this command: > + + :set filetype + +In this file the output is: + + filetype=help ~ + +Thus you would use "help" for {filetype}. + For the {directory} part you need to use your runtime directory. Look at +the output of this command: > + + set runtimepath + +Now use the first item, the name before the first comma. Thus if the output +looks like this: + + runtimepath=~/.vim,/usr/local/share/vim/vim60/runtime,~/.vim/after ~ + +You use "~/.vim" for {directory}. Then the resulting file name is: + + ~/.vim/indent/help.vim ~ + +Instead of switching the indenting off, you could write your own indent file. +How to do that is explained here: |indent-expression|. + +============================================================================== +*30.4* Other indenting + +The most simple form of automatic indenting is with the 'autoindent' option. +It uses the indent from the previous line. A bit smarter is the 'smartindent' +option. This is useful for languages where no indent file is available. +'smartindent' is not as smart as 'cindent', but smarter than 'autoindent'. + With 'smartindent' set, an extra level of indentation is added for each { +and removed for each }. An extra level of indentation will also be added for +any of the words in the 'cinwords' option. Lines that begin with # are +treated specially: all indentation is removed. This is done so that +preprocessor directives will all start in column 1. The indentation is +restored for the next line. + + +CORRECTING INDENTS + +When you are using 'autoindent' or 'smartindent' to get the indent of the +previous line, there will be many times when you need to add or remove one +'shiftwidth' worth of indent. A quick way to do this is using the CTRL-D and +CTRL-T commands in Insert mode. + For example, you are typing a shell script that is supposed to look like +this: + + if test -n a; then ~ + echo a ~ + echo "-------" ~ + fi ~ + +Start off by setting these options: > + + :set autoindent shiftwidth=3 + +You start by typing the first line, <Enter> and the start of the second line: + + if test -n a; then ~ + echo ~ + +Now you see that you need an extra indent. Type CTRL-T. The result: + + if test -n a; then ~ + echo ~ + +The CTRL-T command, in Insert mode, adds one 'shiftwidth' to the indent, no +matter where in the line you are. + You continue typing the second line, <Enter> and the third line. This time +the indent is OK. Then <Enter> and the last line. Now you have this: + + if test -n a; then ~ + echo a ~ + echo "-------" ~ + fi ~ + +To remove the superfluous indent in the last line press CTRL-D. This deletes +one 'shiftwidth' worth of indent, no matter where you are in the line. + When you are in Normal mode, you can use the ">>" and "<<" commands to +shift lines. ">" and "<" are operators, thus you have the usual three ways to +specify the lines you want to indent. A useful combination is: > + + >i{ + +This adds one indent to the current block of lines, inside {}. The { and } +lines themselves are left unmodified. ">a{" includes them. In this example +the cursor is on "printf": + + original text after ">i{" after ">a{" + + if (flag) if (flag) if (flag) ~ + { { { ~ + printf("yes"); printf("yes"); printf("yes"); ~ + flag = 0; flag = 0; flag = 0; ~ + } } } ~ + +============================================================================== +*30.5* Tabs and spaces + +'tabstop' is set to eight by default. Although you can change it, you quickly +run into trouble later. Other programs won't know what tabstop value you +used. They probably use the default value of eight, and your text suddenly +looks very different. Also, most printers use a fixed tabstop value of eight. +Thus it's best to keep 'tabstop' alone. (If you edit a file which was written +with a different tabstop setting, see |25.3| for how to fix that.) + For indenting lines in a program, using a multiple of eight spaces makes +you quickly run into the right border of the window. Using a single space +doesn't provide enough visual difference. Many people prefer to use four +spaces, a good compromise. + Since a <Tab> is eight spaces and you want to use an indent of four spaces, +you can't use a <Tab> character to make your indent. There are two ways to +handle this: + +1. Use a mix of <Tab> and space characters. Since a <Tab> takes the place of + eight spaces, you have fewer characters in your file. Inserting a <Tab> + is quicker than eight spaces. Backspacing works faster as well. + +2. Use spaces only. This avoids the trouble with programs that use a + different tabstop value. + +Fortunately, Vim supports both methods quite well. + + +SPACES AND TABS + +If you are using a combination of tabs and spaces, you just edit normally. +The Vim defaults do a fine job of handling things. + You can make life a little easier by setting the 'softtabstop' option. +This option tells Vim to make the <Tab> key look and feel as if tabs were set +at the value of 'softtabstop', but actually use a combination of tabs and +spaces. + After you execute the following command, every time you press the <Tab> key +the cursor moves to the next 4-column boundary: > + + :set softtabstop=4 + +When you start in the first column and press <Tab>, you get 4 spaces inserted +in your text. The second time, Vim takes out the 4 spaces and puts in a <Tab> +(thus taking you to column 8). Thus Vim uses as many <Tab>s as possible, and +then fills up with spaces. + When backspacing it works the other way around. A <BS> will always delete +the amount specified with 'softtabstop'. Then <Tab>s are used as many as +possible and spaces to fill the gap. + The following shows what happens pressing <Tab> a few times, and then using +<BS>. A "." stands for a space and "------->" for a <Tab>. + + type result ~ + <Tab> .... + <Tab><Tab> -------> + <Tab><Tab><Tab> ------->.... + <Tab><Tab><Tab><BS> -------> + <Tab><Tab><Tab><BS><BS> .... + +An alternative is to use the 'smarttab' option. When it's set, Vim uses +'shiftwidth' for a <Tab> typed in the indent of a line, and a real <Tab> when +typed after the first non-blank character. However, <BS> doesn't work like +with 'softtabstop'. + + +JUST SPACES + +If you want absolutely no tabs in your file, you can set the 'expandtab' +option: > + + :set expandtab + +When this option is set, the <Tab> key inserts a series of spaces. Thus you +get the same amount of white space as if a <Tab> character was inserted, but +there isn't a real <Tab> character in your file. + The backspace key will delete each space by itself. Thus after typing one +<Tab> you have to press the <BS> key up to eight times to undo it. If you are +in the indent, pressing CTRL-D will be a lot quicker. + + +CHANGING TABS IN SPACES (AND BACK) + +Setting 'expandtab' does not affect any existing tabs. In other words, any +tabs in the document remain tabs. If you want to convert tabs to spaces, use +the ":retab" command. Use these commands: > + + :set expandtab + :%retab + +Now Vim will have changed all indents to use spaces instead of tabs. However, +all tabs that come after a non-blank character are kept. If you want these to +be converted as well, add a !: > + + :%retab! + +This is a little bit dangerous, because it can also change tabs inside a +string. To check if these exist, you could use this: > + + /"[^"\t]*\t[^"]*" + +It's recommended not to use hard tabs inside a string. Replace them with +"\t" to avoid trouble. + +The other way around works just as well: > + + :set noexpandtab + :%retab! + +============================================================================== +*30.6* Formatting comments + +One of the great things about Vim is that it understands comments. You can +ask Vim to format a comment and it will do the right thing. + Suppose, for example, that you have the following comment: + + /* ~ + * This is a test ~ + * of the text formatting. ~ + */ ~ + +You then ask Vim to format it by positioning the cursor at the start of the +comment and type: > + + gq]/ + +"gq" is the operator to format text. "]/" is the motion that takes you to the +end of a comment. The result is: + + /* ~ + * This is a test of the text formatting. ~ + */ ~ + +Notice that Vim properly handled the beginning of each line. + An alternative is to select the text that is to be formatted in Visual mode +and type "gq". + +To add a new line to the comment, position the cursor on the middle line and +press "o". The result looks like this: + + /* ~ + * This is a test of the text formatting. ~ + * ~ + */ ~ + +Vim has automatically inserted a star and a space for you. Now you can type +the comment text. When it gets longer than 'textwidth', Vim will break the +line. Again, the star is inserted automatically: + + /* ~ + * This is a test of the text formatting. ~ + * Typing a lot of text here will make Vim ~ + * break ~ + */ ~ + +For this to work some flags must be present in 'formatoptions': + + r insert the star when typing <Enter> in Insert mode + o insert the star when using "o" or "O" in Normal mode + c break comment text according to 'textwidth' + +See |fo-table| for more flags. + + +DEFINING A COMMENT + +The 'comments' option defines what a comment looks like. Vim distinguishes +between a single-line comment and a comment that has a different start, end +and middle part. + Many single-line comments start with a specific character. In C++ // is +used, in Makefiles #, in Vim scripts ". For example, to make Vim understand +C++ comments: > + + :set comments=:// + +The colon separates the flags of an item from the text by which the comment is +recognized. The general form of an item in 'comments' is: + + {flags}:{text} + +The {flags} part can be empty, as in this case. + Several of these items can be concatenated, separated by commas. This +allows recognizing different types of comments at the same time. For example, +let's edit an e-mail message. When replying, the text that others wrote is +preceded with ">" and "!" characters. This command would work: > + + :set comments=n:>,n:! + +There are two items, one for comments starting with ">" and one for comments +that start with "!". Both use the flag "n". This means that these comments +nest. Thus a line starting with ">" may have another comment after the ">". +This allows formatting a message like this: + + > ! Did you see that site? ~ + > ! It looks really great. ~ + > I don't like it. The ~ + > colors are terrible. ~ + What is the URL of that ~ + site? ~ + +Try setting 'textwidth' to a different value, e.g., 80, and format the text by +Visually selecting it and typing "gq". The result is: + + > ! Did you see that site? It looks really great. ~ + > I don't like it. The colors are terrible. ~ + What is the URL of that site? ~ + +You will notice that Vim did not move text from one type of comment to +another. The "I" in the second line would have fit at the end of the first +line, but since that line starts with "> !" and the second line with ">", Vim +knows that this is a different kind of comment. + + +A THREE PART COMMENT + +A C comment starts with "/*", has "*" in the middle and "*/" at the end. The +entry in 'comments' for this looks like this: > + + :set comments=s1:/*,mb:*,ex:*/ + +The start is defined with "s1:/*". The "s" indicates the start of a +three-piece comment. The colon separates the flags from the text by which the +comment is recognized: "/*". There is one flag: "1". This tells Vim that the +middle part has an offset of one space. + The middle part "mb:*" starts with "m", which indicates it is a middle +part. The "b" flag means that a blank must follow the text. Otherwise Vim +would consider text like "*pointer" also to be the middle of a comment. + The end part "ex:*/" has the "e" for identification. The "x" flag has a +special meaning. It means that after Vim automatically inserted a star, +typing / will remove the extra space. + +For more details see |format-comments|. + +============================================================================== + +Next chapter: |usr_31.txt| Exploiting the GUI + +Copyright: see |manual-copyright| vim:tw=78:ts=8:noet:ft=help:norl: |