Tag Archives: Vim

File Encodings in Vim

By default, You need to guide Vim to decode double-byte encodings like GBK and Big5. The default Vim configuration only works well with Unicode encodings including utf-8, utf-16, utf-16be etc..Edit your .vimrc file, add line like:

Now Vim is able to detect and decode GBK and Big5 encodings automatically. And according my experience, Vim respects utf-16 and utf-16be files only they have BOM byes. Otherwise, these files are wrongly decoded. In this case, you may want to manually reopen the file using a correct encoding. The Vim command like:

And Vim does not store BOM when saving by default. To enable/disable BOM saving, use:

I’ve attached a series of text files to learn the usage. These text file all contains string “123你好”, but saved in different encodings. Let’s list their code points first:

1 2 3
GBK 0x31 0x32 0x33 0xc4e3 0xbac3
Big5 0x31 0x32 0x33 0xa741 0xa66e
Unicode 0x31 0x32 0x33 0x4f60 0x597d
UTF-8 encoded 0x31 0x32 0x33 0xe4bda0 0xe5a5bd

And our hexdump’s here, note the byte order:

My test text files are here. More info:

Vim Tips in Ubuntu 10.04

The objective of this article is to make Vim your programmer’s editor.

First, a normal version of Vim should be installed to enable syntax highlighting. The default installation of Ubuntu 10.04 only contains a compact version “vim-tiny”:

Then copy a local vim configure file:

1. Line Number

Add line into the .vimrc file:

A similar command can be used to show/hide line number when editing on the fly:

Related help:

2. Tab-space Conversion

From the Vim help:

'tabstop' 'ts'          number  (default 8)
                        local to buffer
        Number of spaces that a  in the file counts for.  Also see
        |:retab| command, and 'softtabstop' option.

        Note: Setting 'tabstop' to any other value than 8 can make your file
        appear wrong in many places (e.g., when printing it).

        There are four main ways to use tabs in Vim:
        1. Always keep 'tabstop' at 8, set 'softtabstop' and 'shiftwidth' to 4
           (or 3 or whatever you prefer) and use 'noexpandtab'.  Then Vim
           will use a mix of tabs and spaces, but typing  and  will
           behave like a tab appears every 4 (or 3) characters.
        2. Set 'tabstop' and 'shiftwidth' to whatever you prefer and use
           'expandtab'.  This way you will always insert spaces.  The
           formatting will never be messed up when 'tabstop' is changed.
        3. Set 'tabstop' and 'shiftwidth' to whatever you prefer and use a
           |modeline| to set these values when editing the file again.  Only
           works when using Vim to edit the file.
        4. Always set 'tabstop' and 'shiftwidth' to the same value, and
           'noexpandtab'.  This should then work (for initial indents only)
           for any tabstop setting that people use.  It might be nice to have
           tabs after the first non-blank inserted as spaces if you do this
           though.  Otherwise aligned comments will be wrong when 'tabstop' is
           changed.

I will choose to use the 2nd approach, so add:

The auto-indent feature is also useful:

When setting expandtab, a real tab can be input by <Ctrl-v>_<Tab>

Related help:

3. Option ‘modeline’:

If you start editing a new file, and the ‘modeline’ option is on, a number of lines at the beginning and end of the file are checked for modelines. This is simply enabled by adding:

Your C/C++ comment may look like one of the following:

And likely, the Python comments:

Here, ai, et, ts and sw are just abbreviations. And expandtab is an option only in Vim, not Vi.

Read related help by typing:

4. Using Taglist:

There are lots of useful scripts in the Vim website that we can use. But Actually, Ubuntu repository also has some of them included:

After installation, these scripts are just downloaded, but not installed for your Vim. We list available script by typing:

Output on Lucid 10.04:

The Taglist plugin is described here, while OmniCppComplete plugin in next section. Both of them make use of ctags utility. Install it first:

Now install the Taglist plugin to your Vim:

When editing a supported file type, Show the taglist window can be opened by one of the following:

Move your cursor between windows by <Ctrl-w>_w as usual. You may want to add a shortcut to toggle this feature. Add lines to your .vimrc file per official document:

When your cursor hovers on a function, <Ctrl-]> takes you to its declaration, while <Ctrl-t> takes you back.

More help:

5. Using OmniCppComplete:

Vim include basic support for code completion. The simplest way is to use <Ctrl-p>. Vim will search your include headers and do insertion. See the screenshot:

vim_ctrlp

The include search path can be set by:

More help info:

Next, Vim provides basic C language completion using ctags. No C++ is supported. Additional languages script can be found in Vim’s autoload directory, say /usr/share/vim/vim72/autoload. But you should generate necessary ctags index files first. For libc6 header files:

And add lines to .vimrc file:

Omni completion can be issued by <Ctrl-x>_<Ctrl-o>.

Screenshot showing function prototype:

vim_omni_c1

Screenshot showing struct member completion:

vim_omni_c2

More help info:

Note, the ccomplete does not work well in C++ completion. So we need to install OmniCppComplete plugin:

Generate ctags index for libstdc++ and qt4:

And add lines to .vimrc file:

You may encounter problems when completing STL functions. Refer to :help omnicpp-faq and find the solution. Anyway, it works all good for me. Here’re screenshots showing STL and Qt code completion:

vim_omni_cpp1

vim_omni_cpp2

!!!NOTE!!! : The tags file for current file must be generated for OmniCppComplete to work. I’ve set Ctrl+F12 as the accelerate key. Otherwise, you’ll get “Pattern not found” error. More help:

Finally, the list of lines adding to my .vimrc file: