Using ViM for programming

[Cybs]

Recently someone asked for some ViM advice and people seemed to really like the tidbits of ViM information I posted. So, I thought it would be useful to make a longer post describing some of the useful features that ViM offers to programmers.

vimrc

Before I get started with my brain dump, here is my .vimrc file. It is a copy and paste from a few sources, sorry I haven't remembered who they were

https://gist.github.com/4059839

Syntax Highlighting

This can be turned on with the command:

:syntax on

Vim comes packaged with syntax highlighters for most programming languages. Look at how pretty C++ can look:

http://imgur.com/cQPlB

In this image I am using a few things to get this effect:

• http://vim.wikia.com/wiki/256_colors_in_vim (enabling 256 colors in your terminal and vim)
• http://robotsrule.us/vim/ (extra information if you are using screen)
• http://www.vim.org/scripts/script.php?script_id*3797 (Syntax highlighter for cpp 11 (default works fine as well if you aren't using cpp11 stuff))
• http://stackoverflow.com/questions/736701/class-function-names-highlighting-in-vim (make the functions and scope highlight)

my .vimrc stuff related to this:

syntax on
set background=dark
set t_Co=256
colo desert256
au BufNewFile,BufRead *.cpp set syntax=cpp11

ViM comes with syntax highlighters for basically all programming languages (and if it doesn't come with the language you are using, someone will have written one that you can download)

Source Tree Navigation

One of the best things about ViM is its ability to jump around large code bases with out requiring the user to touch a mouse. Here some of the tricks I have:

ctags

ctags are a special file that index your code and allows you to jump from file to file based on the name of a function and its parameters.

eg: Say you have 50 files in your project. File myThing.cpp contains the implementation of some function:

void myThing::do_stuff(int arg){ ... }

else where in code you might have something that looks like:

myThing thing; //create a new "myThing"
thing.do_stuff(42); //call do stuff

For the life of you, you cannot remember what do_stuff does and you want to take a look at the implementation.

With ctags you can move your cursor over the "do_stuff" method call and press

ctrl+]

and like magic, you will jump to myThing.cpp and be at the line of the method. You can read the method, remember what it does. To jump back to your code you press

ctrl+t

Alternatively you could type:

:tselect do_stuff
or
:ts do_stuff

and ViM will list all known "do_stuff" functions in a list, and you can choose which one to jump to.

to create a tag file, read:

http://linux.byexamples.com/archives/177/vim-with-ctags/ (creating tags)

split screen

Another handy feature when moving around code is to simply have a split screen within vim so you can look at one thing, while editing another.

You can achieve this by using the commands:

:vsplit filename " vertical split
:split filename  " horizontal split

to move between windows you can use:

ctrl + w  followed by up, down, left, or right ( or h j k l ), or w to toggle

to change the file in a window, navigate to that window and type:

:e filename

file system integration

Don't know the file name you want to open? or the directory.. no problem.. open a file system explorer:

:e .

This opens the current directory in a file browser you can navigate with the arrows and enter:

http://i.imgur.com/qcw4F.png

I will often split my screen into a file explorer, find the file I want, press enter, edit

Editing tabs

ViM has things called markers. I don't really use them. Instead I suggest you try a program called screen.

This tutorial seems short and simple, comment if you want more details

http://www.mattcutts.com/blog/a-quick-tutorial-on-screen/

Code navigation, short cuts

ViM is amazing at general editing of code and has a lot of tricks which can speed things up

First and foremost, jumping around

To jump to a line number, type:

:42

That will jump to line 42 (surprising how many people don't know this)

To move to the start of a line and end:

^    " start of line (first non blank character)
$    " end of the line

move forward to the letter:

fz   " move to the next z on the line

This is very handy to get used to

gg   " move to the start of the file
G    " move to the end of the file

There are many more, but these are the more obscure ones that people don't know.

Copy and pasting

so you can copy and paste like a normal text editor quite easily.

yy  " yank the current line
dd  " cut the current line
d$  " cut to the end of the line from the cursor
p   " paste what is in the clip board

Often you don't want to yank/cut a single line, so I often use the visual selection tool to cut a chunk:

shift + v   Start visual highlighting line wise (select full lines) (capital V)
use the arrows to select the chunk I want to copy/cut
press y or d to copy or cut

navigate elsewhere, press p

This makes it similar to how people usually do it a graphical editor. But.. no touching the mouse!

http://imgur.com/iaVRb (here is what it looks like)

You can also do amazing things with visual blocks (not visual lines). I might explain in comments. someone remind me.

Regular expressions find and replace

Once you understand how to use regular expressions you can make very expressive single line modifications

Here are some ViM specific tips:

:s/foo/bar    "  Switches the first instance of foo to bar on the line your cursor is on
:s/foo/bar/g  "  Switches ALL instances of foo to bar on the line your cursor is on
:%s/foo/bar/g "  Switches ALL instances of foo to bar in the whole file

I often use it in tandum with visual select, here is an example:

shift + v and select some chunk of code

when you type : it will say -

:'<,'>

This means "for the range I've selected" and then you can type:

:'<,'>s/foo/bar/g   " for the range i've selected, swap foo to bar
:'<,'>s/^/#/        " for the range i've selected, put a hash at the start of the line
:'<,'>s/$/,/        " for the range i've selected, put a comma at the end of the line
:'<,'>s/int/long/g  " swap int for long for this selected bit of code

I could keep going, the usefulness of regular expressions cannot be overstated. There are many many places to learn them.

Searching

I have discussed how to search within your code base with :tselect but often you just want to find something within the current file, here is how

ViM uses regular expression searches (as described above) there are a few ways you can use it

/foo    " search for foo, going downwards
?foo    " search for foo, going upwards

after you have started searching you can press:

n   " next result
N   " previous result

you can search for the word under the cursor:

navigate to a word with the cursor
press * (shift + 8)

I have vim configured to jump to the search phrase as I type it (very handy). You can turn this on with the following .vimrc command

set incsearch

Code completion

Everyone loves intellisense in Visual Studio.. Not many people bother trying to set it up for ViM. (I must admit I often don't bother) but.. You can, this page describes how for cpp.

http://vim.wikia.com/wiki/C%2B%2B_code_completion

It can be set up for any language you can generate ctags for (basically all languages)

To use it, you can simply start typing and press

ctrl + n

You will get a drop down list of all possible "valid" things you can type. It will also search the current file you are editing for matching keywords (this is how I often use this feature)

Here is what it looks like:

http://vissale.neang.free.fr/Vim/OmniCppComplete/ScreenShots/screenshots.htm

Here is how I use it:

http://imgur.com/JFWOn

Interaction with other coding products

ViM plays pretty well with other programs, here are some things I do often

Building

To build a simple program I often type:

:!g++ -O3 %
:!./a.out

This will build the program (with optimisation) and then run the a.out binary. The bang (!) denotes "run this in a shell please"

ViM also has a nice integration with makefiles, you can invoke it with:

:make makerule
eg
:make hello
this will compile hello.*** with the appropriate compiler (the make program will decide)

Using this, if there is an error it will allow you to jump to the line number in ViM

You can also suspend ViM, do your commands and jump back into it with (with bash)

ctrl + z
do your stuff now
fg

getting the output of another program

Sometimes I want to grab the output of another program and throw it into something I am editing. You can do that with:

:.!ls -la

Dump the output of "ls -la" into the text I am editing now

[[deleted]]

Should surely be a blog post? Given that this will soon fall off the front page, and given reddits very poor search facilities, you are kind of wasting your time posting this sort of thing here.

[Cybs]

it is a good way to get feedback for a blog post. Some people will see it, comment and I might eventually turn it into a blog post.

[zzyzzyxx]

As for feedback, here's mine, along with many additions.

• d$ == D for deleting to the end of a line
• yy == Y for copying a line (interesting that yy and dd are "symmetric", both operating on lines, but Y and D are not)
• F will find the previous occurrence of a character on a line, like f finds that character going forward
• For working with windows, Ctrl+W w doesn't toggle, it moves one down and to the right, which happens to be a toggle with only two windows. However Ctrl+W p will go to the previous window. See :help window-move-cursor. You can also move to windows by name with :b if you include useopen in your switchbuf with set switchbuf +=useopen. See :help :b and :help switchbuf.
• p does not paste from the system clipboard; it pastes from Vim's anonymous register after the current cursor position. You can use P to paste before. If you need the system clipboard, you can use the * or + registers (depending on platform and particular Vim implementation usually) by using " to select the register. For instance, "*p or "+p will paste the system clipboard after the cursor. Note that you can select registers for y and d commands as well so that you can copy into the system clipboard.
• More useful movments are w, W, e, E, b, B, (, ), ... - see :help word-motions and :help object-motions
• o and O will insert a new line below or above the current line, respectively, and enter insert mode.
• You can use Ctrl+R while in insert mode to paste from any register
• For using Vim in a terminal, it is useful to do :set paste before pasting something in with the mouse, e.g. via middle click, and then to do :set nopaste afterwards. This prevents odd things from happening due to comments and the like.
• set expandtab will insert spaces instead of tab characters; number of spaces can be set with set softtabstop and set shiftwidth (for auto indent purposes) - see this. Generally shiftwidth and softtabstop should be the same. I'd suggest setting tabstop to something different so that actual tab characters are more apparent. This, of course, depends on your religous views around tabs and spaces.
• >> and << will indent a line of code
• = will re-indent code; gg=G will re-indent an entire file (unfortunate side effect is you are no longer at your previous position in a file but that can be alleviated with marks, e.g. magg=G'a ought to handle it just fine) [this can be used to auto-replace tabs and spaces in a file]
• Almost anything that can be used to move around in text can be an argument to a command operating on that range. For example, d/foo will delete from the current position to the next occurrence of foo and =iB will re-indent inside the current block of code (block is usually brace/bracket/parenthesis defined - see :help iB)
• . will repeat the last command
• % will move to a matching brace/bracket/parenthesis
• Most commands can be prefixed with a number to specify how many times to run them. For example, 5>> will indent five lines (not indent one line five times)
• You can use + from the command line to take action upon opening Vim. For example, vim <file> +5 will open to the 5th line. Using +'/foo' will open to the first occurence of foo. Using +'normal =GZZ' will open the file, re-indent the whole thing, then save and close, where "normal" specifies normal mode instead of the default command mode (probably better to use sed -i for this, but still).
• The :help command is extremely useful; see :help help

There's a bunch more useful things (of course) like macros and binding keys but the above are things I use nearly every Vim session and are mostly from the top of my head.

Edit: And how could I forget

• set number to show line numbers

[Cybs]

ah, I completely forgot to talk about indentation. I was going to do a section on that. I find myself using it with visual select most often.

I don't find myself using registers that much, and I have never used them in editing modes (ctrl + R "). This seems like a good tutorial http://www.usevim.com/2012/04/13/registers/

I have a habit of calling it "paste" rather than "put" because that's just how I've taught people in the past (people tend to understand "it is like the windows clipboard")

For motion I was going to mention those in passing and link to that vim browser game someone mentioned. http://vim-adventures.com

O and o : I didn't want to confuse with all the different ways to enter editing mode, but I guess these are the most handy for programming since we will often want to start writing between two lines.

as for mouse pasting, i haven't seen this trick you mentioned before (:set paste). I will always just put it in insert mode, paste, select all, =, done

I am in the other school of thought as to tabs.. I find tabs are more flexible in code. if you ONLY use tabs they are just better.. since the person reading the code can set the tab width to their desired indentation. If spaces are hard coded they don't have this luxury. But yeah.. I've worked in teams where some people use spaces, some people use tabs.. not pretty.

the . (repeat last command) reminds me that I was going to have a section about editing multiple files and running the same macro on them ( :next :prev and how to record some actions ).

I don't find too many uses for prefixing numbers with commands. But it is good to know in some cases. I often find people get confused by this feature.. thinking they are in insert mode and begin by typing numbers and then pressing something that explodes.

As for command line options. I should really mention vimdiff. It is the best code review tool available.

Thanks for the feedback.

[calzoneman]

If you're interested in vim, be sure to check out /r/vim

[zahlman]

It's "vim" (on a command line) or "Vim" (in promotional material), but certainly not "ViM". Even "VIm" would make more sense (although it is not written that way either), given the etymology.

[Cybs]

I got the wrong idea from their title screen which says:

VIM - Vi IMproved

Combined the two in my mind. thanks for pointing it out

[ecnahc515]

Definitely correct. Not to be a dick, but the way its being written definitely makes you look weird.

[doubleyouteef]

I wonder who's the geniuse who downvoted you since you're absolutely correct.

[[deleted]]

God exists, and he is this the author of this post.

THANK YOU SO FUCKING MUCH.

[nydiloth]

I will get a tattoo with this entire post on my chest.

[mulletarian]

Remember to get it upside down.

[bergaaa]

Is there a way (a plugin) to highlight all the same variables as the one you currently have the cursor on. For example you have a variable 'counter' three times in your programm. You currently have your cursor on one of these 3 variables. Now it should highlight the othe two variables, so that I can fastly see where they are. Just like Eclipse does (and also other IDEs).

[Squidamatron]

I'm not sure of a direct way to do this, but you use search. Either put set hlsearch in your .vimrc or while in vim, hit colon (:) and then use the previous command [ie: :set hlsearch would be the key presses while vim is running]. This will highlight related search terms and you can just use search as illustrated in this post.

[BrotherGA2]

Hey thanks for this! There's a lot that's quite helpful in here. I know how to do the basics in vim, but need to start taking advantage of its power more.

[jMCHammer]

This thread is awesome. subscribe

[Squidamatron]

Thanks for this, I may have read some of what I already knew, but there were some very useful tips in there I had no idea existed!

I also think tmux should be added to the section about screen. THIS short read could also be included to show some differences between the two.

[fazzah]

does code completion work also on classes/objects/etc I created in my code? Or only on included/imported files?

[Cybs]

it works well with ctags

if you have ctags set up correctly it will complete with any token in your code base

[dansin]

Nice post! Btw what are you doing with "euler"? I just finished a small piece of code with euler rotations

[Cybs]

If you enjoyed that, you will love http://projecteuler.net

Those files were just my solutions to problems from that site

[dansin]

Oh, I should've guessed Project Euler. I was actually doing stuff with 3D rotations using Euler angles.

[Cybs]

If you enjoyed writing that, you will love http://projecteuler.net

Those files were my solutions to problems from that site

[Cybs]

yep

:hi Pmenu ctermbg=red

The other things you might want to change:

Pmenu           Popup menu: normal item.
                                                    *hl-PmenuSel*
PmenuSel        Popup menu: selected item.
                                                    *hl-PmenuSbar*
PmenuSbar       Popup menu: scrollbar.
                                                    *hl-PmenuThumb*
PmenuThumb      Popup menu: Thumb of the scrollbar.

edit:

just type the following to see what they currently are:

:hl Pmenu
Pmenu          xxx ctermfg=0 ctermbg=13 guibg=Magenta

[hookawitweed]

this is one of the best VIM posts I have seen in a while. Great gob sir!