I love Vim; It’s simple, yet powerful. I think, Vim with few custom settings and plugins are quite efficient as IDEs (Integrated Development Environments). IDE’s offer lot more features (Integrated Debuggers etc) but a lot of time, I do not need most of the features and in many of the cases, all I need is code completion, and syntax error highlighting support in Vim. YouCompleteMe is pefect for my needs and I found this gem few years back when I was still using Syntastic. At that time, I was using Fedora and setting up YouCompleteMe was not so difficult. Can’t say the same for Arch Linux :(

I use a very minimal Arch Linux distribution and maybe because of that, I had to go extra mile to get things working. I needed YouCompleteMe support for C family language and Python 3 on a very minimal Arch Linux installation. What started as a 10 mins jaunt, ended up into around 8 hours of battle, but alas I raised my glass of water and was triumphant (Too bad, no one was recording this event and like many others, this will not go into history books). So for souls like me, who dared to tread on this path and still lurk in deep forest, here’s the gameplay :)

Environment:

Distribution: Arch Linux

Vim Plugin: YCM (YouCompleteMe)

Language Support: C, C++, Python 3

Steps

1. Download YCM package using Vundle. If Vundle vim plugin is not already installed, install it first.

2. Without C language semantic support

   • Installation

    mkdir ~/ycm_build
    cd ~/ycm_build
    cmake -G "Unix Makefiles" . ~/.vim/bundle/YouCompleteMe/third_party/ycmd/cpp
    cmake --build . --target ycm_core
   

2. With C language semantic support
   • Download the clang binary (clang+llvm-4.0.0-x86_64-linux-gnu-ubuntu-16.04) I’ve dowloaded the prebuilt binary for ubuntu (Though I have Arch Linux installation as I could not find one for Arch Linux) and it seem to work.

   Create a directory and keep this downloaded binary under this directory

    mkdir -p ~/ycm_temp/prebuilt
    file ~/ycm_temp/prebuilt/clang+llvm-4.0.0-x86_64-linux-gnu-ubuntu-16.04
    /home/amit/ycm_temp/prebuilt/clang+llvm-4.0.0-x86_64-linux-gnu-ubuntu-16.04: directory
   

   • Build/install prerequisites

    sudo pacman -Sy pkg-config
    sudo pacman -Sy fakeroot
    git clone https://aur.archlinux.org/package-query.git
    cd package-query
    makepkg -si
    cd ..
    git clone https://aur.archlinux.org/yaourt.git
    cd yaourt
    makepkg -si
    cd ..
    sudo pacman-key --refresh-key
    gpg --keyserver pgp.mit.edu --recv-keys C52048C0C0748FEE227D47A2702353E0F7E48EDB
    gpg --keyserver keys.gnupg.net --recv-keys 702353E0F7E48EDB
    yaourt -S ncurses5-compat-libs
   

   • Build YCM with python 2 or 3 support

    mkdir ~/ycm_build
    cd ~/ycm_build
   

   • Python 2 support (Skip if you need YCM to support Python 3 along with C family languages

    cmake -G "Unix Makefiles" -DPATH_TO_LLVM_ROOT=/home/amit/ycm_temp/prebuilt/clang+llvm-4.0.0-x86_64-linux-gnu-ubuntu-16.04 . ~/.vim/bundle/YouCompleteMe/third_party/ycmd/cpp
   

   • Python 3 support

    cmake -G "Unix Makefiles" -DPATH_TO_LLVM_ROOT=/home/amit/ycm_temp/prebuilt/clang+llvm-4.0.0-x86_64-linux-gnu-ubuntu-16.04 -DPYTHON_INCLUDE_DIR=/usr/include/python3.6m -DPYTHON_LIBRARY=/usr/lib/libpython3.6m.so -DUSE_PYTHON2=OFF . ~/.vim/bundle/YouCompleteMe/third_party/ycmd/cpp
   

   • Build YCM

    cmake --build . --target ycm_core
   

3. Update .vimrc

   • For python 2

    let g:ycm_server_python_interpreter = '/usr/bin/python2.7'
    let g:ycm_python_binary_path = '/usr/bin/python2.7'
   

   • For python 3

    let g:ycm_server_python_interpreter = '/usr/bin/python3.6'
    let g:ycm_python_binary_path = '/usr/bin/python3.6'
   

4. Use .ycm_extra_conf file (sample version is available under ycm source directory) to make changes for C or C++ semantic completion. Put that edited file at the top of the C or C++ project directory.

Notes

1. Python

The code completion will work for the python version for which the YCM was built. Therefore, if YCM doesn’t seem to work, check the YcmDebugInfo and the python version.