How to build Vim against specific Ruby version

Let's say you installed your Vim editor as a system package. Likely it was compiled against Ruby 1.8.7. But what if you need Vim compiled with Ruby 1.9.x? I'm gonna tell you how to do it.

Clone vim repository

Make sure you have installed mercurial package:

$ sudo apt-get install mercurial

Clone Vim repository from google code:

$ hg clone https://vim.googlecode.com/hg/ vim_sources
$ cd vim_sources

Patching

There is no option to specify Ruby version to compile Vim against. But it's easy to patch vim sources to force it to use 1.9 instead of 1.8.

Open file src/Make_mvc.mak in vim sources directory.

Find lines like this:

#
# Support Ruby interface
#
!ifdef RUBY
#  Set default value
!ifndef RUBY_VER
RUBY_VER = 18
!endif
!ifndef RUBY_VER_LONG
RUBY_VER_LONG = 1.8
!endif

Replace 18 and 1.8 with 19 and 1.9. So it should look this way:

#
# Support Ruby interface
#
!ifdef RUBY
#  Set default value
!ifndef RUBY_VER
RUBY_VER = 19
!endif
!ifndef RUBY_VER_LONG
RUBY_VER_LONG = 1.9
!endif

Configure and compile

At first make sure your current ruby version is which one you need:

$ rvm use 1.9.3 --default
$ ruby -v
ruby 1.9.3p194 (2012-04-20 revision 35410) [x86_64-linux]

No we are ready to run ./configure script:

$ ./configure --enable-rubyinterp=yes --prefix=/where/you/want/ruby/to/be/installed/

If everything is OK we can go ahead and compile it:

$ make -j 3

-j option defines number of processes to make builing faster. It's useful if number of CPU cores is greater than one.

Finally install built Vim to /where/you/want/ruby/to/be/installed/ directory which you passed as --prefix option:

$ make install

Verify Ruby version

Now let's open your new Vim:

$ cd /where/you/want/ruby/to/be/installed/
$ ./bin/vim

And run the next command:

:ruby puts RUBY_DESCRIPTION

The ouput should looks similar to this:

ruby 1.9.3p194 (2012-04-20 revision 35410) [x86_64-linux]

So, everything is OK. Enjoy Vim and builtin ruby 1.9 ;)