Now vim has a non-backtracking regexp engine!

Vim 7.4 was just released and it has a new regexp engine which does not backtrack! According to the help,

Vim includes two regexp engines:
1. An old, backtracking engine that supports everything.
2. A new, NFA engine that works much faster on some patterns, but
   does not support everything.

Vim will automatically select the right engine for you.  However,
if you run into a problem or want to specifically select one
engine or the other, you can prepend one of the following to the
pattern:

	\%#=0	Force automatic selection.  Only has an effect when
	        'regexpengine' has been set to a non-zero value.
	\%#=1	Force using the old engine.
	\%#=2	Force using the NFA engine.

You can also use the 'regexpengine' option to change the default.

So this is analogous to the situation with Perl--- by default, Vim will decide which engine to use for a given expression. But using those prefixes, it's more like the situation with Python and Ruby--- we decide which engine to use.

Here's what I did to install Vim 7.4 on my Linux machine

$ wget ftp://ftp.vim.org/pub/vim/unix/vim-7.4.tar.bz2 
$ tar xf vim-7.4.tar.bz2 
$ cd vim74/
$ ./configure --prefix=/opt/vim74
$ make
$ make test
$ sudo make install

Now give it a whirl!

$ /opt/vim74/bin/vim

Note that if you use Vim with a GUI, you might need to help it find the version you want. I ran the above commands on a Xubuntu 13.04 machine and when I ran

$ /opt/vim74/bin/gvim

I got Athena widgets, which looked out of place amongst all of the pretty Xfce things. Turns out I hadn't run

$ sudo apt-get install gnome-devel

yet on this machine, so Vim couldn't find what it needed. After running that command, I rebuilt Vim and now I get GTK2 widgets (at first, I thought I would need to run configure with the --enable-gui=gtk2 option, but that's not the case; it will discover that on its own).

Happy matching!