YouCompleteMe is a fast, as-you-type, fuzzy-search code completion engine for Vim. It has several completion engines:
- an identifier-based engine that works with every programming language,
- a Clang-based engine that provides native semantic code completion for C/C++/Objective-C/Objective-C++ (from now on referred to as "the C-family languages"),
- a Jedi-based completion engine for Python,
- an OmniSharp-based completion engine for C#,
- a Gocode-based completion engine for Go,
- a TSServer-based completion engine for TypeScript,
- a Tern-based completion engine for JavaScript.
- and an omnifunc-based completer that uses data from Vim's omnicomplete system to provide semantic completions for many other languages (Ruby, PHP etc.).
Here's an explanation of what happens in the short GIF demo above.
First, realize that no keyboard shortcuts had to be pressed to get the list of completion candidates at any point in the demo. The user just types and the suggestions pop up by themselves. If the user doesn't find the completion suggestions relevant and/or just wants to type, they can do so; the completion engine will not interfere.
When the user sees a useful completion string being offered, they press the TAB key to accept it. This inserts the completion string. Repeated presses of the TAB key cycle through the offered completions.
If the offered completions are not relevant enough, the user can continue typing to further filter out unwanted completions.
A critical thing to notice is that the completion filtering is NOT based on
the input being a string prefix of the completion (but that works too). The
input needs to be a subsequence match of a completion. This is a fancy way
of saying that any input characters need to be present in a completion string in
the order in which they appear in the input. So abc is a subsequence of
xaybgc, but not of xbyxaxxc. After the filter, a complicated sorting system
ranks the completion strings so that the most relevant ones rise to the top of
the menu (so you usually need to press TAB just once).
All of the above works with any programming language because of the identifier-based completion engine. It collects all of the identifiers in the current file and other files you visit (and your tags files) and searches them when you type (identifiers are put into per-filetype groups).
The demo also shows the semantic engine in use. When the user presses ., ->
or :: while typing in insert mode (for C++; different triggers are used for
other languages), the semantic engine is triggered (it can also be triggered
with a keyboard shortcut; see the rest of the docs).
The last thing that you can see in the demo is YCM's diagnostic display features (the little red X that shows up in the left gutter; inspired by Syntastic) if you are editing a C-family file. As Clang compiles your file and detects warnings or errors, they will be presented in various ways. You don't need to save your file or press any keyboard shortcut to trigger this, it "just happens" in the background.
In essence, YCM obsoletes the following Vim plugins because it has all of their features plus extra:
- clang_complete
- AutoComplPop
- Supertab
- neocomplcache
YCM also provides semantic go-to-definition/declaration commands for C-family languages & Python. Expect more IDE features powered by the various YCM semantic engines in the future.
You'll also find that YCM has filepath completers (try typing ./ in a file)
and a completer that integrates with UltiSnips.
Please refer to the full Installation Guide below; the following commands are provided on a best-effort basis and may not work for you.
Install the latest version of MacVim. Yes, MacVim. And yes, the latest.
If you don't use the MacVim GUI, it is recommended to use the Vim binary that is
inside the MacVim.app package (MacVim.app/Contents/MacOS/Vim). To ensure it
works correctly copy the mvim script from the MacVim download to your
local binary folder (for example /usr/local/bin/mvim) and then symlink it:
ln -s /usr/local/bin/mvim vim
Install YouCompleteMe with Vundle.
Remember: YCM is a plugin with a compiled component. If you update YCM using Vundle and the ycm_support_libs library APIs have changed (happens rarely), YCM will notify you to recompile it. You should then rerun the install process.
NOTE: If you want C-family completion, you MUST have the latest Xcode
installed along with the latest Command Line Tools (they are installed
automatically when you run clang for the first time, or manually by running
xcode-select --install)
Install CMake. Preferably with Homebrew, but here's the stand-alone CMake installer.
If you have installed a Homebrew Python and/or Homebrew MacVim, see the FAQ for details.
Compiling YCM with semantic support for C-family languages:
cd ~/.vim/bundle/YouCompleteMe
./install.py --clang-completer
Compiling YCM without semantic support for C-family languages:
cd ~/.vim/bundle/YouCompleteMe
./install.py
The following additional language support options are available:
- C# support: add
--omnisharp-completerto./install.py - Go support: ensure go is installed and add
--gocode-completer - TypeScript support: install nodejs and npm then install the
TypeScript SDK with
npm install -g typescript. - JavaScript support: install nodejs and npm and add
--tern-completerto./install.py
For example, to install with all language features, ensure npm, go, mono and typescript API are installed and in your PATH, then:
cd ~/.vim/bundle/YouCompleteMe
./install.py --clang-completer --omnisharp-completer --gocode-completer --tern-completer
That's it. You're done. Refer to the User Guide section on how to use YCM. Don't forget that if you want the C-family semantic completion engine to work, you will need to provide the compilation flags for your project to YCM. It's all in the User Guide.
YCM comes with sane defaults for its options, but you still may want to take a look at what's available for configuration. There are a few interesting options that are conservatively turned off by default that you may want to turn on.
Please refer to the full Installation Guide below; the following commands are provided on a best-effort basis and may not work for you.
Make sure you have Vim 7.3.598 with python2 support. Ubuntu 14.04 and later have
a Vim that's recent enough. You can see the version of Vim installed by running
vim --version. If the version is too old, you may need to compile Vim
from source (don't worry, it's easy).
Install YouCompleteMe with Vundle.
Remember: YCM is a plugin with a compiled component. If you update YCM using Vundle and the ycm_support_libs library APIs have changed (happens rarely), YCM will notify you to recompile it. You should then rerun the install process.
Install development tools and CMake: sudo apt-get install build-essential cmake
Make sure you have Python headers installed: sudo apt-get install python-dev.
Compiling YCM with semantic support for C-family languages:
cd ~/.vim/bundle/YouCompleteMe
./install.py --clang-completer
Compiling YCM without semantic support for C-family languages:
cd ~/.vim/bundle/YouCompleteMe
./install.py
The following additional language support options are available:
- C# support: add
--omnisharp-completerto./install.py - Go support: ensure go is installed and add
--gocode-completer - TypeScript support: install nodejs and npm then install the
TypeScript SDK with
npm install -g typescript. - JavaScript support: install nodejs and npm and add
--tern-completerto./install.py
For example, to install with all language features, ensure node, go, mono and typescript API are installed and in your PATH, then:
cd ~/.vim/bundle/YouCompleteMe
./install.py --clang-completer --omnisharp-completer --gocode-completer --tern-completer
That's it. You're done. Refer to the User Guide section on how to use YCM. Don't forget that if you want the C-family semantic completion engine to work, you will need to provide the compilation flags for your project to YCM. It's all in the User Guide.
YCM comes with sane defaults for its options, but you still may want to take a look at what's available for configuration. There are a few interesting options that are conservatively turned off by default that you may want to turn on.
Please refer to the full Installation Guide below; the following commands are provided on a best-effort basis and may not work for you.
Make sure you have Vim 7.3.598 with python2 support. Fedora 21 and later have
a Vim that's recent enough. You can see the version of Vim installed by running
vim --version. If the version is too old, you may need to compile Vim
from source (don't worry, it's easy).
Install YouCompleteMe with Vundle.
Remember: YCM is a plugin with a compiled component. If you update YCM using Vundle and the ycm_support_libs library APIs have changed (happens rarely), YCM will notify you to recompile it. You should then rerun the install process.
Install development tools and CMake: sudo dnf install automake gcc gcc-c++ kernel-devel cmake
Make sure you have Python headers installed: sudo dnf install python-devel.
Compiling YCM with semantic support for C-family languages:
cd ~/.vim/bundle/YouCompleteMe
./install.py --clang-completer
Compiling YCM without semantic support for C-family languages:
cd ~/.vim/bundle/YouCompleteMe
./install.py
The following additional language support options are available:
- C# support: add
--omnisharp-completerto./install.py - Go support: ensure go is installed and add
--gocode-completer - TypeScript support: install nodejs and npm then install the
TypeScript SDK with
npm install -g typescript. - JavaScript support: install nodejs and npm and add
--tern-completerto./install.py
For example, to install with all language features, ensure node, go, mono and typescript API are installed and in your PATH, then:
cd ~/.vim/bundle/YouCompleteMe
./install.py --clang-completer --omnisharp-completer --gocode-completer --tern-completer
That's it. You're done. Refer to the User Guide section on how to use YCM. Don't forget that if you want the C-family semantic completion engine to work, you will need to provide the compilation flags for your project to YCM. It's all in the User Guide.
YCM comes with sane defaults for its options, but you still may want to take a look at what's available for configuration. There are a few interesting options that are conservatively turned off by default that you may want to turn on.
Please refer to the full Installation Guide below; the following commands are provided on a best-effort basis and may not work for you.
Important: we assume that you are using the cmd.exe command prompt and
that you know how to add an executable to the PATH environment variable.
Make sure you have at least Vim 7.3.598 with python2 support. You can check the
version by typing :version inside Vim. Take note of the Vim architecture, i.e.
32 or 64-bit. It will be important when choosing the python2 installer. We
recommend using a 64-bit client. Don't worry, a frequently updated copy of
64-bit Vim is available.
Install YouCompleteMe with Vundle.
Remember: YCM is a plugin with a compiled component. If you update YCM using Vundle and the ycm_support_libs library APIs have changed (happens rarely), YCM will notify you to recompile it. You should then rerun the install process.
Download and install the following software:
- python2. Be sure to pick the version corresponding to your Vim architecture. It is Windows x86-64 MSI installer if you are using the Vim previously linked.
- CMake. Add CMake executable to the PATH environment variable.
- Visual Studio. Download the community edition. During setup, choose Custom as the installation type and select the Visual C++ component.
- 7-zip. Required to build YCM with semantic support for C-family languages.
Compiling YCM with semantic support for C-family languages:
cd %USERPROFILE%/vimfiles/bundle/YouCompleteMe
install.py --clang-completer
Compiling YCM without semantic support for C-family languages:
cd %USERPROFILE%/vimfiles/bundle/YouCompleteMe
install.py
The following additional language support options are available:
- C# support: add
--omnisharp-completerto./install.py - Go support: ensure go is installed and add
--gocode-completer - TypeScript support: install nodejs and npm then install the
TypeScript SDK with
npm install -g typescript. - JavaScript support: install nodejs and npm and add
--tern-completerto./install.py
For example, to install with all language features, ensure npm, go, mono and
typescript API are installed and in your %PATH%, then:
cd %USERPROFILE%/vimfiles/bundle/YouCompleteMe
python install.py --clang-completer --omnisharp-completer --gocode-completer --tern-completer
You can specify the Microsoft Visual C++ (MSVC) version using the --msvc
option. YCM officially supports MSVC 11 (Visual Studio 2012), 12 (2013), and 14
(2015).
That's it. You're done. Refer to the User Guide section on how to use YCM. Don't forget that if you want the C-family semantic completion engine to work, you will need to provide the compilation flags for your project to YCM. It's all in the User Guide.
YCM comes with sane defaults for its options, but you still may want to take a look at what's available for configuration. There are a few interesting options that are conservatively turned off by default that you may want to turn on.
Please refer to the full Installation Guide below; the following commands are provided on a best-effort basis and may not work for you. OpenBSD / FreeBSD are not officially supported platforms by YCM.
Make sure you have Vim 7.3.598 with python2 support.
OpenBSD 5.5 and later have a Vim that's recent enough. You can see the version of
Vim installed by running vim --version.
FreeBSD 10.x comes with clang compiler but not the libraries needed to install.
pkg install llvm35 boost-all boost-python-libs clang35
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/llvm35/lib/
Install YouCompleteMe with Vundle.
Remember: YCM is a plugin with a compiled component. If you update YCM using Vundle and the ycm_support_libs library APIs have changed (happens rarely), YCM will notify you to recompile it. You should then rerun the install process.
Install dependencies and CMake: sudo pkg_add llvm boost cmake
Compiling YCM with semantic support for C-family languages:
cd ~/.vim/bundle/YouCompleteMe
./install.py --clang-completer --system-libclang --system-boost
Compiling YCM without semantic support for C-family languages:
cd ~/.vim/bundle/YouCompleteMe
./install.py --system-boost
The following additional language support options are available:
- C# support: add
--omnisharp-completerto./install.py - Go support: ensure go is installed and add
--gocode-completer - TypeScript support: install nodejs and npm then install the
TypeScript SDK with
npm install -g typescript. - JavaScript support: install nodejs and npm and add
--tern-completerto./install.py
For example, to install with all language features, ensure npm, go, mono and typescript API are installed and in your PATH, then:
cd ~/.vim/bundle/YouCompleteMe
./install.py --clang-completer --omnisharp-completer --gocode-completer --tern-completer
That's it. You're done. Refer to the User Guide section on how to use YCM. Don't forget that if you want the C-family semantic completion engine to work, you will need to provide the compilation flags for your project to YCM. It's all in the User Guide.
YCM comes with sane defaults for its options, but you still may want to take a look at what's available for configuration. There are a few interesting options that are conservatively turned off by default that you may want to turn on.
These are the steps necessary to get YCM working on a Unix OS and on Windows.
Note to Windows users: we assume that you are running the cmd.exe command
prompt and that the needed executables are in the PATH environment variable. Do
not just copy the shell commands. Replace ~ by %USERPROFILE% in them and use
the right Vim home directory. It should be vimfiles by default instead of
.vim.
See the FAQ if you have any issues.
Remember: YCM is a plugin with a compiled component. If you update YCM using Vundle and the ycm_support_libs library APIs have changed (happens rarely), YCM will notify you to recompile it. You should then rerun the install process.
Please follow the instructions carefully. Read EVERY WORD.
-
Ensure that your version of Vim is at least 7.3.598 and that it has support for python2 scripting.
Inside Vim, type
:version. Look at the first two to three lines of output; it should sayVi IMproved X.Y, where X.Y is the major version of vim. If your version is greater than 7.3, then you're all set. If your version is 7.3 then look below that where it says,Included patches: 1-Z, where Z will be some number. That number needs to be 598 or higher.If your version of Vim is not recent enough, you may need to compile Vim from source (don't worry, it's easy).
After you have made sure that you have Vim 7.3.598+, type the following in Vim:
:echo has('python'). The output should be 1. If it's 0, then get a version of Vim with Python support.On Windows, check also if your Vim architecture is 32 or 64-bit. This is critical because it must match the python2 and the YCM libraries architectures. We recommend using a 64-bit Vim.
-
Install YCM with Vundle (or Pathogen, but Vundle is a better idea). With Vundle, this would mean adding a
Plugin 'Valloric/YouCompleteMe'line to your vimrc.If you don't install YCM with Vundle, make sure you have run
git submodule update --init --recursiveafter checking out the YCM repository (Vundle will do this for you) to fetch YCM's dependencies. -
[Complete this step ONLY if you care about semantic completion support for C-family languages. Otherwise it's not necessary.]
Download the latest version of
libclang. Clang is an open-source compiler that can compile C/C++/Objective-C/Objective-C++. Thelibclanglibrary it provides is used to power the YCM semantic completion engine for those languages. YCM is designed to work with libclang version 3.6 or higher, but can in theory work with any 3.2+ version as well.You can use the system libclang only if you are sure it is version 3.3 or higher, otherwise don't. Even if it is, we recommend using the official binaries from llvm.org if at all possible. Make sure you download the correct archive file for your OS.
We STRONGLY recommend AGAINST use of the system libclang instead of the upstream compiled binaries. Random things may break. Save yourself the hassle and use the upstream pre-built libclang.
-
Compile the
ycm_support_libslibraries that YCM needs. These libs are the C++ engines that YCM uses to get fast completions.You will need to have
cmakeinstalled in order to generate the required makefiles. Linux users can install cmake with their package manager (sudo apt-get install cmakefor Ubuntu) whereas other users can download and install cmake from its project site. Mac users can also get it through Homebrew withbrew install cmake.On a Unix OS, you need to make sure you have Python headers installed. On a Debian-like Linux distro, this would be
sudo apt-get install python-dev. On Mac they should already be present.On Windows, you need to download and install python2. Pick the version corresponding to your Vim architecture. You will also need Microsoft Visual C++ (MSVC) to build YCM. You can obtain it by installing Visual Studio. MSVC 11 (Visual Studio 2012), 12 (2013), and 14 (2015) are officially supported.
Here we'll assume you installed YCM with Vundle. That means that the top-level YCM directory is in
~/.vim/bundle/YouCompleteMe.We'll create a new folder where build files will be placed. Run the following:
cd ~ mkdir ycm_build cd ycm_buildNow we need to generate the makefiles. If you DON'T care about semantic support for C-family languages, run the following command in the
ycm_builddirectory:cmake -G "<generator>" . ~/.vim/bundle/YouCompleteMe/third_party/ycmd/cppwhere
<generator>isUnix Makefileson Unix systems and one of the following Visual Studio generators on Windows:Visual Studio 11 2012 Win64Visual Studio 12 2013 Win64Visual Studio 14 2015 Win64
Remove the
Win64part in these generators if your Vim architecture is 32-bit.For those who want to use the system version of boost, you would pass
-DUSE_SYSTEM_BOOST=ONto cmake. This may be necessary on some systems where the bundled version of boost doesn't compile out of the box.NOTE: We STRONGLY recommend AGAINST use of the system boost instead of the bundled version of boost. Random things may break. Save yourself the hassle and use the bundled version of boost.
If you DO care about semantic support for C-family languages, then your
cmakecall will be a bit more complicated. We'll assume you downloaded a binary distribution of LLVM+Clang from llvm.org in step 3 and that you extracted the archive file to folder~/ycm_temp/llvm_root_dir(withbin,lib,includeetc. folders right inside that folder). On Windows, you can extract the files from the LLVM+Clang installer using 7-zip.NOTE: This only works with a downloaded LLVM binary package, not a custom-built LLVM! See docs below for
EXTERNAL_LIBCLANG_PATHwhen using a custom LLVM build.With that in mind, run the following command in the
ycm_builddirectory:cmake -G "<generator>" -DPATH_TO_LLVM_ROOT=~/ycm_temp/llvm_root_dir . ~/.vim/bundle/YouCompleteMe/third_party/ycmd/cppwhere
<generator>is replaced like above.Now that configuration files have been generated, compile the libraries using this command:
cmake --build . --target ycm_support_libs --config ReleaseThe
--config Releasepart is specific to Windows and will be ignored on a Unix OS.For those who want to use the system version of libclang, you would pass
-DUSE_SYSTEM_LIBCLANG=ONto cmake instead of the-DPATH_TO_LLVM_ROOT=...flag.NOTE: We STRONGLY recommend AGAINST use of the system libclang instead of the upstream compiled binaries. Random things may break. Save yourself the hassle and use the upstream pre-built libclang.
You could also force the use of a custom libclang library with
-DEXTERNAL_LIBCLANG_PATH=/path/to/libclang.soflag (the library would end with.dylibon a Mac). Again, this flag would be used instead of the other flags. If you compiled LLVM from source, this is the flag you should be using.Running the
makecommand will also place thelibclang.[so|dylib|dll]in theYouCompleteMe/third_party/ycmdfolder for you if you compiled with clang support (it needs to be there for YCM to work). -
Set up support for additional languages, as desired:
-
C# support: Navigate to
YouCompleteMe/third_party/ycmd/third_party/OmniSharpServerand runmsbuild(Windows) orxbuild(other platforms, using mono) depending on your platform. If mono is not installed, install it. -
Go support: If go is not installed on your system, install it and add it to your path. Navigate to
YouCompleteMe/third_party/ycmd/third_party/gocodeand rungo build. -
TypeScript support: As with the quick installation, simply
npm install -g typescriptafter successfully installing nodejs and npm. -
JavaScript support: Install nodejs and npm. Then navigate to
YouCompleteMe/third_party/ycmd/third_party/ternand runnpm install --production
That's it. You're done. Refer to the User Guide section on how to use YCM. Don't forget that if you want the C-family semantic completion engine to work, you will need to provide the compilation flags for your project to YCM. It's all in the User Guide.
YCM comes with sane defaults for its options, but you still may want to take a look at what's available for configuration. There are a few interesting options that are conservatively turned off by default that you may want to turn on.
- Super-fast identifier completer including tags files and syntax elements
- Intelligent suggestion ranking and filtering
- File and path suggestions
- Suggestions from Vim's OmniFunc
- UltiSnips snippet suggestions
- Semantic auto-completion
- Real-time diagnostic display
- Go to include/declaration/definition (
GoTo, etc.) - Semantic type information for identifiers (
GetType) - Automatically fix certain errors (
FixIt) - View documentation comments for identifiers (
GetDoc)
- Semantic auto-completion
- Real-time diagnostic display
- Go to declaration/definition (
GoTo, etc.) - Semantic type information for identifiers (
GetType) - Automatically fix certain errors (
FixIt) - Management of OmniSharp server instance
- View documentation comments for identifiers (
GetDoc)
- Intelligent auto-completion
- Go to declaration/definition (
GoTo, etc.) - View documentation comments for identifiers (
GetDoc)
- Semantic auto-completion
- Management of
gocodeserver instance
- Semantic auto-completion
- Go to definition (
GoToDefinition) - Semantic type information for identifiers (
GetType) - View documentation comments for identifiers (
GetDoc)
- Intelligent auto-completion
- Go to definition, find references (
GoToDefinition,GoToReferences) - Type information for identifiers (
GetType) - View documentation comments for identifiers (
GetDoc) - Management of
Ternserver instance
- If the offered completions are too broad, keep typing characters; YCM will continue refining the offered completions based on your input.
- Filtering is "smart-case" sensitive; if you are typing only lowercase letters, then it's case-insensitive. If your input contains uppercase letters, then the uppercase letters in your query must match uppercase letters in the completion strings (the lowercase letters still match both). So, "foo" matches "Foo" and "foo", "Foo" matches "Foo" and "FOO" but not "foo".
- Use the TAB key to accept a completion and continue pressing TAB to cycle through the completions. Use Shift-TAB to cycle backwards. Note that if you're using console Vim (that is, not Gvim or MacVim) then it's likely that the Shift-TAB binding will not work because the console will not pass it to Vim. You can remap the keys; see the Options section below.
Knowing a little bit about how YCM works internally will prevent confusion. YCM has several completion engines: an identifier-based completer that collects all of the identifiers in the current file and other files you visit (and your tags files) and searches them when you type (identifiers are put into per-filetype groups).
There are also several semantic engines in YCM. There's a libclang-based completer that provides semantic completion for C-family languages. There's a Jedi-based completer for semantic completion for Python. There's also an omnifunc-based completer that uses data from Vim's omnicomplete system to provide semantic completions when no native completer exists for that language in YCM.
There are also other completion engines, like the UltiSnips completer and the filepath completer.
YCM automatically detects which completion engine would be the best in any situation. On occasion, it queries several of them at once, merges the outputs and presents the results to you.
YCM has a client-server architecture; the Vim part of YCM is only a thin client
that talks to the ycmd HTTP+JSON server that has the vast majority of YCM
logic and functionality. The server is started and stopped automatically as you
start and stop Vim.
The subsequence filter removes any completions that do not match the input, but then the sorting system kicks in. It's actually very complicated and uses lots of factors, but suffice it to say that "word boundary" (WB) subsequence character matches are "worth" more than non-WB matches. In effect, this means given an input of "gua", the completion "getUserAccount" would be ranked higher in the list than the "Fooguxa" completion (both of which are subsequence matches). A word-boundary character are all capital characters, characters preceded by an underscore and the first letter character in the completion string.
- You can use Ctrl+Space to trigger the completion suggestions anywhere, even without a string prefix. This is useful to see which top-level functions are available for use.
YCM looks for a .ycm_extra_conf.py file in the directory of the opened file or
in any directory above it in the hierarchy (recursively); when the file is
found, it is loaded (only once!) as a Python module. YCM calls a FlagsForFile
method in that module which should provide it with the information necessary to
compile the current file. You can also provide a path to a global
.ycm_extra_conf.py file, which will be used as a fallback. To prevent the
execution of malicious code from a file you didn't write YCM will ask you once
per .ycm_extra_conf.py if it is safe to load. This can be disabled and you can
white-/blacklist files. See the Options section for more details.
This system was designed this way so that the user can perform any arbitrary sequence of operations to produce a list of compilation flags YCM should hand to Clang.
See YCM's own .ycm_extra_conf.py for details on how this
works. You should be able to use it as a starting point. Don't just
copy/paste that file somewhere and expect things to magically work; your project
needs different flags. Hint: just replace the strings in the flags variable
with compilation flags necessary for your project. That should be enough for 99%
of projects.
Yes, Clang's CompilationDatabase system is also supported. Again,
see the above linked example file. You can get CMake to generate this file for
you by adding set( CMAKE_EXPORT_COMPILE_COMMANDS 1 ) to your project's
CMakeLists.txt file (if using CMake). If you're not using CMake, you could use
something like Bear to generate the compile_commands.json file.
Consider using YCM-Generator to generate the ycm_extra_conf.py file.
If Clang encounters errors when compiling the header files that your file includes, then it's probably going to take a long time to get completions. When the completion menu finally appears, it's going to have a large number of unrelated completion strings (type/function names that are not actually members). This is because Clang fails to build a precompiled preamble for your file if there are any errors in the included headers and that preamble is key to getting fast completions.
Call the :YcmDiags command to see if any errors or warnings were detected in
your file.
-
Ensure that you have enabled the Tern completer. See the installation guide for details.
-
Create a
.tern-projectfile in the root directory of your JavaScript project, by following the instructions in the Tern documentation. -
Make sure that Vim's working directory is a descendent of that directory (or that directory itself) when working with JavaScript files.
JavaScript completion is based on Tern. This completion engine requires a
file named .tern-project to exist in the current working
directory or a directory which is an ancestor of the current working directory
when the tern server is started. YCM starts the Tern server the first time a
JavaScript file is edited, so Vim's working directory at that time needs to be a
descendent of the directory containing the .tern-project file (or that
directory itself).
Alternatively, as described in the Tern documentation, a global
.tern-config file may be used.
Multiple Tern servers, are not supported. To switch to a different JavaScript project, you can do one of the following:
- start a new instance of Vim from the new project's directory
- change Vim's working directory (
:cd /path/to/new/project) and restart theycmdserver (:YcmRestartServer) - change Vim's working directory (
:cd /path/to/new/project), open a JavaScript file (or set filetype to JavaScript) and restart the Tern server using YCM completer subcommands:YcmCompleter StopServerand:YcmCompleter StartServer.
This section contains some advice for configuring .tern-project and working
with JavaScript files. The canonical reference for correctly configuring Tern is
the Tern documentation. Any issues, improvements, advice, etc.
should be sought from the Tern project. For example, see the list of tern
plugins for the list of plugins
which can be enabled in the plugins section of the .tern-project file.
##### Configuring Tern for node support
The following simple example .tern-project file enables nodejs support:
{
"plugins": {
"node": {}
}
}
The Tern requirejs plugin requires that all included "libraries" are rooted
under the same base directory. If that's not the case for your projects, then it
is possible to make it work with appropriate symbolic links. For example, create
a directory ext_lib within your project and populate it with symlinks to your
libraries. Then set up the .tern-project something like this:
{
"plugins": {
"requirejs": {
"baseURL": "./ext_lib",
}
}
}Then, given the following structure:
./ext_lib/mylib (symlink)
./ext_lib/anotherlib (symlink)
Can be used as follows:
define( [ 'mylib/file1', 'anotherlib/anotherfile' ], function( f1, f2 ) {
// etc.
} );Python, C#, Go, and TypeScript are supported natively by YouCompleteMe using the Jedi, Omnisharp, Gocode, and TSServer engines, respectively. Check the installation section for instructions to enable these features if desired.
YCM will use your omnifunc (see :h omnifunc in Vim) as a source for semantic
completions if it does not have a native semantic completion engine for your
file's filetype. Vim comes with okayish omnifuncs for various languages like
Ruby, PHP etc. It depends on the language.
You can get stellar omnifuncs for Java and Ruby with Eclim. Just make sure
you have the latest Eclim installed and configured (this means Eclim >= 2.2.*
and Eclipse >= 4.2.*).
After installing Eclim remember to create a new Eclipse project within your
application by typing :ProjectCreate <path-to-your-project> -n ruby (or -n java)
inside vim and don't forget to have let g:EclimCompletionMethod = 'omnifunc'
in your vimrc. This will make YCM and Eclim play nice; YCM will use Eclim's omnifuncs
as the data source for semantic completions and provide the auto-triggering
and subsequence-based matching (and other YCM features) on top of it.
You have two options here: writing an omnifunc for Vim's omnicomplete system
that YCM will then use through its omni-completer, or a custom completer for YCM
using the Completer API.
Here are the differences between the two approaches:
- You have to use VimScript to write the omnifunc, but get to use Python to write for the Completer API; this by itself should make you want to use the API.
- The Completer API is a much more powerful way to integrate with YCM and it provides a wider set of features. For instance, you can make your Completer query your semantic back-end in an asynchronous fashion, thus not blocking Vim's GUI thread while your completion system is processing stuff. This is impossible with VimScript. All of YCM's completers use the Completer API.
- Performance with the Completer API is better since Python executes faster than VimScript.
If you want to use the omnifunc system, see the relevant Vim docs with :h complete-functions. For the Completer API, see the API docs.
If you want to upstream your completer into YCM's source, you should use the Completer API.
YCM will display diagnostic notifications for C-family and C# languages if you compiled YCM with Clang and Omnisharp support, respectively. Since YCM continuously recompiles your file as you type, you'll get notified of errors and warnings in your file as fast as possible.
Here are the various pieces of the diagnostic UI:
- Icons show up in the Vim gutter on lines that have a diagnostic.
- Regions of text related to diagnostics are highlighted (by default, a red
wavy underline in
gvimand a red background invim). - Moving the cursor to a line with a diagnostic echoes the diagnostic text.
- Vim's location list is automatically populated with diagnostic data (off by default, see options).
The new diagnostics (if any) will be displayed the next time you press any key on the keyboard. So if you stop typing and just wait for the new diagnostics to come in, that will not work. You need to press some key for the GUI to update.
Having to press a key to get the updates is unfortunate, but cannot be changed due to the way Vim internals operate; there is no way that a background task can update Vim's GUI after it has finished running. You have to press a key. This will make YCM check for any pending diagnostics updates.
You can force a full, blocking compilation cycle with the
:YcmForceCompileAndDiagnostics command (you may want to map that command to a
key; try putting nnoremap <F5> :YcmForceCompileAndDiagnostics<CR> in your
vimrc). Calling this command will force YCM to immediately recompile your file
and display any new diagnostics it encounters. Do note that recompilation with
this command may take a while and during this time the Vim GUI will be
blocked.
YCM will display a short diagnostic message when you move your cursor to the
line with the error. You can get a detailed diagnostic message with the
<leader>d key mapping (can be changed in the options) YCM provides when your
cursor is on the line with the diagnostic.
You can also see the full diagnostic message for all the diagnostics in the
current file in Vim's locationlist, which can be opened with the :lopen and
:lclose commands (make sure you have set let g:ycm_always_populate_location_list = 1 in your vimrc). A good way to toggle
the display of the locationlist with a single key mapping is provided by
another (very small) Vim plugin called ListToggle (which also makes it
possible to change the height of the locationlist window), also written by
yours truly.
Unlike the C-family diagnostic support, the C# diagnostic support is not a full
compile run. Instead, it is a simple syntax check of the current file only.
The :YcmForceCompileAndDiagnostics command also is only a simple syntax check,
not a compile. This means that only syntax errors will be displayed, and not
semantic errors. For example, omitting the semicolon at the end of statement
will be displayed as a diagnostic error, but using a nonexistent class or
variable will not be.
You can change the styling for the highlighting groups YCM uses. For the signs in the Vim gutter, the relevant groups are:
YcmErrorSign, which falls back to groupSyntasticErrorSignand thenerrorif they existYcmWarningSign, which falls back to groupSyntasticWarningSignand thentodoif they exist
You can also style the line that has the warning/error with these groups:
YcmErrorLine, which falls back to groupSyntasticErrorLineif it existsYcmWarningLine, which falls back to groupSyntasticWarningLineif it exists
Note that the line highlighting groups only work when gutter signs are turned on.
The syntax groups used to highlight regions of text with errors/warnings:
YcmErrorSection, which falls back to groupSyntasticErrorif it exists and thenSpellBadYcmWarningSection, which falls back to groupSyntasticWarningif it exists and thenSpellCap
Here's how you'd change the style for a group:
highlight YcmErrorLine guibg=#3f0000If the ycmd completion server suddenly stops for some reason, you can restart
it with this command.
Calling this command will force YCM to immediately recompile your file and display any new diagnostics it encounters. Do note that recompilation with this command may take a while and during this time the Vim GUI will be blocked.
You may want to map this command to a key; try putting nnoremap <F5> :YcmForceCompileAndDiagnostics<CR> in your vimrc.
Calling this command will fill Vim's locationlist with errors or warnings if
any were detected in your file and then open it. If a given error or warning can
be fixed by a call to :YcmCompleter FixIt, then (FixIt available) is
appended to the error or warning text. See the FixIt completer subcommand for
more information.
NOTE: The absense of (FixIt available) does not strictly imply a fix-it is
not available as not all completers are able to provide this indication. For
example, the c-sharp completer provides many fix-its but does not add this
additional indication.
The g:ycm_open_loclist_on_ycm_diags option can be used to prevent the location
list from opening, but still have it filled with new diagnostic data. See the
Options section for details.
This command shows the full diagnostic text when the user's cursor is on the line with the diagnostic.
This will print out various debug information for the current file. Useful to see what compile commands will be used for the file if you're using the semantic completion engine.
This command automatically opens in windows the stdout and stderr logfiles
written by the ycmd server. If one or both logfiles are already opened, they
are automatically closed. stderr or stdout can be specified as an argument
of this command to only open the corresponding logfile instead of both. If this
logfile is already opened, it will be closed. Only for debugging purpose.
This command can be used to invoke completer-specific commands. If the first
argument is of the form ft=... the completer for that file type will be used
(for example ft=cpp), else the native completer of the current buffer will be
used.
Call YcmCompleter without further arguments for information about the
commands you can call for the selected completer.
See the YcmCompleter subcommands section for more information on the available subcommands.
[See the docs for the YcmCompleter command before tackling this section.]
The invoked subcommand is automatically routed to the currently active semantic
completer, so :YcmCompleter GoToDefinition will invoke the GoToDefinition
subcommand on the Python semantic completer if the currently active file is a
Python one and on the Clang completer if the currently active file is a
C/C++/Objective-C one.
You may also want to map the subcommands to something less verbose; for
instance, nnoremap <leader>jd :YcmCompleter GoTo<CR>
maps the <leader>jd sequence to the longer subcommand invocation.
The various GoTo* subcommands add entries to Vim's jumplist so you can use
CTRL-O to jump back to where you where before invoking the command (and
CTRL-I to jump forward; see :h jumplist for details).
Looks up the current line for a header and jumps to it.
Supported in filetypes: c, cpp, objc, objcpp
Looks up the symbol under the cursor and jumps to its declaration.
Supported in filetypes: c, cpp, objc, objcpp, python, cs
Looks up the symbol under the cursor and jumps to its definition.
NOTE: For C-family languages this only works in certain situations, namely when
the definition of the symbol is in the current translation unit. A translation
unit consists of the file you are editing and all the files you are including
with #include directives (directly or indirectly) in that file.
Supported in filetypes: c, cpp, objc, objcpp, python, cs, typescript, javascript
This command tries to perform the "most sensible" GoTo operation it can. Currently, this means that it tries to look up the symbol under the cursor and jumps to its definition if possible; if the definition is not accessible from the current translation unit, jumps to the symbol's declaration. For C/C++/Objective-C, it first tries to look up the current line for a header and jump to it. For C#, implementations are also considered and preferred.
Supported in filetypes: c, cpp, objc, objcpp, python, cs, javascript
WARNING: This command trades correctness for speed!
Same as the GoTo command except that it doesn't recompile the file with
libclang before looking up nodes in the AST. This can be very useful when you're
editing files that take long to compile but you know that you haven't made any
changes since the last parse that would lead to incorrect jumps. When you're
just browsing around your codebase, this command can spare you quite a bit of
latency.
Supported in filetypes: c, cpp, objc, objcpp
This command attempts to find all of the references within the project to the identifier under the cursor and populates the quickfix list with those locations.
Supported in filetypes: javascript
YCM caches the flags it gets from the FlagsForFile function in your
ycm_extra_conf.py file if you return them with the do_cache parameter set to
True. The cache is in memory and is never invalidated (unless you restart Vim
of course).
This command clears that cache entirely. YCM will then re-query your
FlagsForFile function as needed in the future.
Supported in filetypes: c, cpp, objc, objcpp
Echos the type of the variable or method under the cursor, and where it differs, the derived type.
For example:
std::string s;Invoking this command on s returns std::string => std::basic_string<char>
NOTE: Due to limitations of libclang, invoking this command on the word
auto typically returns auto. However, invoking it on a usage of the variable
with inferred type returns the correct type, but typically it is repeated due to
libclang returning that the types differ.
For example:
const char *s = "String";
auto x = &s; // invoking on x or auto returns "auto";
// invoking on s returns "const char *"
std::cout << *x; // invoking on x returns "const char ** => const char **"NOTE: Causes re-parsing of the current translation unit.
Supported in filetypes: c, cpp, objc, objcpp, typescript, javascript
Echos the semantic parent of the point under the cursor.
The semantic parent is the item that semantically contains the given position.
For example:
class C {
void f();
};
void C::f() {
}In the out-of-line definition of C::f, the semantic parent is the class C,
of which this function is a member.
In the example above, both declarations of C::f have C as their semantic
context, while the lexical context of the first C::f is C and the lexical
context of the second C::f is the translation unit.
For global declarations, the semantic parent is the translation unit.
NOTE: Causes re-parsing of the current translation unit.
Supported in filetypes: c, cpp, objc, objcpp
Where available, attempts to make changes to the buffer to correct the diagnostic closest to the cursor position.
Completers which provide diagnostics may also provide trivial modifications to the source in order to correct the diagnostic. Examples include syntax errors such as missing trailing semi-colons, spurious characters, or other errors which the semantic engine can deterministically suggest corrections.
If no fix-it is available for the current line, or there is no diagnostic on the current line, this command has no effect on the current buffer. If any modifications are made, the number of changes made to the buffer is echo'd and the user may use the editor's undo command to revert.
When a diagnostic is available, and g:ycm_echo_current_diagnostic is set to 1,
then the text (FixIt) is appended to the echo'd diagnostic when the
completer is able to add this indication. The text (FixIt available) is
also appended to the diagnostic text in the output of the :YcmDiags command
for any diagnostics with available fix-its (where the completer can provide this
indication).
NOTE: Causes re-parsing of the current translation unit.
NOTE: After applying a fix-it, the diagnostics UI is not immediately updated.
This is due to a technical restriction in vim, and moving the cursor, or issuing
the the :YcmForceCompileAndDiagnostics command will refresh the diagnostics.
Repeated invocations of the FixIt command on a given line, however, do apply
all diagnostics as expected without requiring refreshing of the diagnostics UI.
This is particularly useful where there are multiple diagnostics on one line, or
where after fixing one diagnostic, another fix-it is available.
Supported in filetypes: c, cpp, objc, objcpp, cs
Displays the preview window populated with quick info about the identifier under the cursor. This includes, depending on the language, things like:
- The type or declaration of identifier
- Doxygen/javadoc comments
- Python docstrings
- etc.
Supported in filetypes: c, cpp, objc, objcpp, cs, python, typescript, javascript
Starts the semantic-engine-as-localhost-server for those semantic engines that work as separate servers that YCM talks to.
Supported in filetypes: cs, javascript, go
Stops the semantic-engine-as-localhost-server for those semantic engines that work as separate servers that YCM talks to.
Supported in filetypes: cs, javascript, go
Restarts the semantic-engine-as-localhost-server for those semantic engines that work as separate servers that YCM talks to.
Supported in filetypes: cs
Instruct the Omnisharp server to clear its cache and reload all files from disk. This is useful when files are added, removed, or renamed in the solution, files are changed outside of Vim, or whenever Omnisharp cache is out-of-sync.
Supported in filetypes: cs
Looks up the symbol under the cursor and jumps to its implementation (i.e. non-interface). If there are multiple implementations, instead provides a list of implementations to choose from.
Supported in filetypes: cs
Looks up the symbol under the cursor and jumps to its implementation if one, else jump to its declaration. If there are multiple implementations, instead provides a list of implementations to choose from.
Supported in filetypes: cs
Get the number of YCM Diagnostic errors. If no errors are present, this function returns 0.
For example:
call youcompleteme#GetErrorCount()Both this function and youcompleteme#GetWarningCount can be useful when
integrating YCM with other Vim plugins. For example, a lightline user could
add a diagnostics section to their statusline which would display the number of
errors and warnings.
Get the number of YCM Diagnostic warnings. If no warnings are present, this function returns 0.
For example:
call youcompleteme#GetWarningCount()All options have reasonable defaults so if the plug-in works after installation you don't need to change any options. These options can be configured in your vimrc script by including a line like this:
let g:ycm_min_num_of_chars_for_completion = 1Note that after changing an option in your [vimrc script] vimrc you have to restart Vim for the changes to take effect.
This option controls the number of characters the user needs to type before
identifier-based completion suggestions are triggered. For example, if the
option is set to 2, then when the user types a second alphanumeric character
after a whitespace character, completion suggestions will be triggered. This
option is NOT used for semantic completion.
Setting this option to a high number like 99 effectively turns off the
identifier completion engine and just leaves the semantic engine.
Default: 2
let g:ycm_min_num_of_chars_for_completion = 2This option controls the minimum number of characters that a completion candidate coming from the identifier completer must have to be shown in the popup menu.
A special value of 0 means there is no limit.
NOTE: This option only applies to the identifier completer; it has no effect on the various semantic completers.
Default: 0
let g:ycm_min_num_identifier_candidate_chars = 0When set to 0, this option turns off YCM's identifier completer (the
as-you-type popup) and the semantic triggers (the popup you'd get after typing
. or -> in say C++). You can still force semantic completion with the
<C-Space> shortcut.
If you want to just turn off the identifier completer but keep the semantic
triggers, you should set g:ycm_min_num_of_chars_for_completion to a high
number like 99.
Default: 1
let g:ycm_auto_trigger = 1This option controls for which Vim filetypes (see :h filetype) should YCM be
turned on. The option value should be a Vim dictionary with keys being filetype
strings (like python, cpp etc) and values being unimportant (the dictionary
is used like a hash set, meaning that only the keys matter).
The * key is special and matches all filetypes. By default, the whitelist
contains only this * key.
YCM also has a g:ycm_filetype_blacklist option that lists filetypes for which
YCM shouldn't be turned on. YCM will work only in filetypes that both the
whitelist and the blacklist allow (the blacklist "allows" a filetype by not
having it as a key).
For example, let's assume you want YCM to work in files with the cpp filetype.
The filetype should then be present in the whitelist either directly (cpp key
in the whitelist) or indirectly through the special * key. It should not be
present in the blacklist.
Filetypes that are blocked by the either of the lists will be completely ignored by YCM, meaning that neither the identifier-based completion engine nor the semantic engine will operate in them.
You can get the filetype of the current file in Vim with :set ft?.
Default: {'*' : 1}
let g:ycm_filetype_whitelist = { '*': 1 }This option controls for which Vim filetypes (see :h filetype) should YCM be
turned off. The option value should be a Vim dictionary with keys being filetype
strings (like python, cpp etc) and values being unimportant (the dictionary
is used like a hash set, meaning that only the keys matter).
See the g:ycm_filetype_whitelist option for more details on how this works.
Default: [see next line]
let g:ycm_filetype_blacklist = {
\ 'tagbar' : 1,
\ 'qf' : 1,
\ 'notes' : 1,
\ 'markdown' : 1,
\ 'unite' : 1,
\ 'text' : 1,
\ 'vimwiki' : 1,
\ 'pandoc' : 1,
\ 'infolog' : 1,
\ 'mail' : 1
\}This option controls for which Vim filetypes (see :h filetype) should the YCM
semantic completion engine be turned off. The option value should be a Vim
dictionary with keys being filetype strings (like python, cpp etc) and
values being unimportant (the dictionary is used like a hash set, meaning that
only the keys matter). The listed filetypes will be ignored by the YCM semantic
completion engine, but the identifier-based completion engine will still trigger
in files of those filetypes.
Note that even if semantic completion is not turned off for a specific filetype, you will not get semantic completion if the semantic engine does not support that filetype.
You can get the filetype of the current file in Vim with :set ft?.
Default: [see next line]
let g:ycm_filetype_specific_completion_to_disable = {
\ 'gitcommit': 1
\}When set, this option turns on YCM's diagnostic display features. See the Diagnostic display section in the User Manual for more details.
Specific parts of the diagnostics UI (like the gutter signs, text highlighting, diagnostic echo and auto location list population) can be individually turned on or off. See the other options below for details.
Note that YCM's diagnostics UI is only supported for C-family languages.
When set, this option also makes YCM remove all Syntastic checkers set for the
c, cpp, objc and objcpp filetypes since this would conflict with YCM's
own diagnostics UI.
If you're using YCM's identifier completer in C-family languages but cannot use the clang-based semantic completer for those languages and want to use the GCC Syntastic checkers, unset this option.
Default: 1
let g:ycm_show_diagnostics_ui = 1YCM will use the value of this option as the symbol for errors in the Vim gutter.
This option is part of the Syntastic compatibility layer; if the option is not
set, YCM will fall back to the value of the g:syntastic_error_symbol option
before using this option's default.
Default: >>
let g:ycm_error_symbol = '>>'YCM will use the value of this option as the symbol for warnings in the Vim gutter.
This option is part of the Syntastic compatibility layer; if the option is not
set, YCM will fall back to the value of the g:syntastic_warning_symbol option
before using this option's default.
Default: >>
let g:ycm_warning_symbol = '>>'When this option is set, YCM will put icons in Vim's gutter on lines that have a
diagnostic set. Turning this off will also turn off the YcmErrorLine and
YcmWarningLine highlighting.
This option is part of the Syntastic compatibility layer; if the option is not
set, YCM will fall back to the value of the g:syntastic_enable_signs option
before using this option's default.
Default: 1
let g:ycm_enable_diagnostic_signs = 1When this option is set, YCM will highlight regions of text that are related to the diagnostic that is present on a line, if any.
This option is part of the Syntastic compatibility layer; if the option is not
set, YCM will fall back to the value of the g:syntastic_enable_highlighting
option before using this option's default.
Default: 1
let g:ycm_enable_diagnostic_highlighting = 1When this option is set, YCM will echo the text of the diagnostic present on the
current line when you move your cursor to that line. If a FixIt is available
for the current diagnostic, then (FixIt) is appended.
This option is part of the Syntastic compatibility layer; if the option is not
set, YCM will fall back to the value of the g:syntastic_echo_current_error
option before using this option's default.
Default: 1
let g:ycm_echo_current_diagnostic = 1When this option is set, YCM will populate the location list automatically every time it gets new diagnostic data. This option is off by default so as not to interfere with other data you might have placed in the location list.
See :help location-list in Vim to learn more about the location list.
This option is part of the Syntastic compatibility layer; if the option is not
set, YCM will fall back to the value of the
g:syntastic_always_populate_loc_list option before using this option's
default.
Default: 0
let g:ycm_always_populate_location_list = 0When this option is set, :YcmDiags will automatically open the location list
after forcing a compilation and filling the list with diagnostic data.
See :help location-list in Vim to learn more about the location list.
Default: 1
let g:ycm_open_loclist_on_ycm_diags = 1When this option is set to 1, YCM will change the updatetime Vim option to
2000 (see :h updatetime). This may conflict with some other plugins you have
(but it's unlikely). The updatetime option is the number of milliseconds that
have to pass before Vim's CursorHold (see :h CursorHold) event fires. YCM
runs the completion engines' "file comprehension" systems in the background on
every such event; the identifier-based engine collects the identifiers whereas
the semantic engine compiles the file to build an AST.
The Vim default of 4000 for updatetime is a bit long, so YCM reduces
this. Set this option to 0 to force YCM to leave your updatetime setting
alone.
Default: 1
let g:ycm_allow_changing_updatetime = 1When this option is set to 1, YCM will show the completion menu even when
typing inside comments.
Default: 0
let g:ycm_complete_in_comments = 0When this option is set to 1, YCM will show the completion menu even when
typing inside strings.
Note that this is turned on by default so that you can use the filename
completion inside strings. This is very useful for instance in C-family files
where typing #include " will trigger the start of filename completion. If you
turn off this option, you will turn off filename completion in such situations
as well.
Default: 1
let g:ycm_complete_in_strings = 1When this option is set to 1, YCM's identifier completer will also collect
identifiers from strings and comments. Otherwise, the text in comments and
strings will be ignored.
Default: 0
let g:ycm_collect_identifiers_from_comments_and_strings = 0When this option is set to 1, YCM's identifier completer will also collect
identifiers from tags files. The list of tags files to examine is retrieved from
the tagfiles() Vim function which examines the tags Vim option. See :h 'tags' for details.
YCM will re-index your tags files if it detects that they have been modified.
The only supported tag format is the Exuberant Ctags format. The
format from "plain" ctags is NOT supported. Ctags needs to be called with the
--fields=+l option (that's a lowercase L, not a one) because YCM needs the
language:<lang> field in the tags output.
See the FAQ for pointers if YCM does not appear to read your tag files.
This option is off by default because it makes Vim slower if your tags are on a network directory.
Default: 0
let g:ycm_collect_identifiers_from_tags_files = 0When this option is set to 1, YCM's identifier completer will seed its
identifier database with the keywords of the programming language you're
writing.
Since the keywords are extracted from the Vim syntax file for the filetype, all keywords may not be collected, depending on how the syntax file was written. Usually at least 95% of the keywords are successfully extracted.
Default: 0
let g:ycm_seed_identifiers_with_syntax = 0If you're using semantic completion for C-family files, this option might come
handy; it's a way of sending data from Vim to your FlagsForFile function in
your .ycm_extra_conf.py file.
This option is supposed to be a list of VimScript expression strings that are
evaluated for every request to the ycmd server and then passed to your
FlagsForFile function as a client_data keyword argument.
For instance, if you set this option to ['v:version'], your FlagsForFile
function will be called like this:
# The '704' value is of course contingent on Vim 7.4; in 7.3 it would be '703'
FlagsForFile(filename, client_data = {'v:version': 704})So the client_data parameter is a dictionary mapping Vim expression strings to
their values at the time of the request.
The correct way to define parameters for your FlagsForFile function:
def FlagsForFile(filename, **kwargs):You can then get to client_data with kwargs['client_data'].
Default: []
let g:ycm_extra_conf_vim_data = []YCM will by default search for an appropriate Python interpreter on your system. You can use this option to override that behavior and force the use of a specific interpreter of your choosing.
NOTE: This interpreter is only used for the ycmd server. The YCM client
running inside Vim always uses the Python interpreter that's embedded inside
Vim.
Default: ''
let g:ycm_path_to_python_interpreter = ''When this option is set to 1, the ycmd completion server will keep the
logfiles around after shutting down (they are deleted on shutdown by default).
To see where the logfiles are, call :YcmDebugInfo.
Default: 0
let g:ycm_server_keep_logfiles = 0The logging level that the ycmd completion server uses. Valid values are the
following, from most verbose to least verbose:
debuginfowarningerrorcritical
Note that debug is very verbose.
Default: info
let g:ycm_server_log_level = 'info'When set to 1, the OmniSharp server will be automatically started (once per
Vim session) when you open a C# file.
Default: 1
let g:ycm_auto_start_csharp_server = 1When set to 1, the OmniSharp server will be automatically stopped upon
closing Vim.
Default: 1
let g:ycm_auto_stop_csharp_server = 1When g:ycm_auto_start_csharp_server is set to 1, specifies the port for
the OmniSharp server to listen on. When set to 0 uses an unused port provided
by the OS.
Default: 0
let g:ycm_csharp_server_port = 0By default, when YCM inserts a namespace, it will insert the using statement
under the nearest using statement. You may prefer that the using statement is
inserted somewhere, for example, to preserve sorting. If so, you can set this
option to override this behaviour.
When this option is set, instead of inserting the using statement itself, YCM
will set the global variable g:ycm_namespace_to_insert to the namespace to
insert, and then evaluate this option's value as an expression. The option's
expression is responsible for inserting the namespace - the default insertion
will not occur.
Default: ''
let g:ycm_csharp_insert_namespace_expr = ''When this option is set to 1, YCM will add the preview string to Vim's
completeopt option (see :h completeopt). If your completeopt option
already has preview set, there will be no effect. You can see the current
state of your completeopt setting with :set completeopt? (yes, the question
mark is important).
When preview is present in completeopt, YCM will use the preview window at
the top of the file to store detailed information about the current completion
candidate (but only if the candidate came from the semantic engine). For
instance, it would show the full function prototype and all the function
overloads in the window if the current completion is a function name.
Default: 0
let g:ycm_add_preview_to_completeopt = 0When this option is set to 1, YCM will auto-close the preview window after
the user accepts the offered completion string. If there is no preview window
triggered because there is no preview string in completeopt, this option is
irrelevant. See the g:ycm_add_preview_to_completeopt option for more details.
Default: 0
let g:ycm_autoclose_preview_window_after_completion = 0When this option is set to 1, YCM will auto-close the preview window after
the user leaves insert mode. This option is irrelevant if
g:ycm_autoclose_preview_window_after_completion is set or if no preview
window is triggered. See the g:ycm_add_preview_to_completeopt option for more
details.
Default: 0
let g:ycm_autoclose_preview_window_after_insertion = 0This option controls the maximum number of diagnostics shown to the user when errors or warnings are detected in the file. This option is only relevant if you are using the C-family semantic completion engine.
Default: 30
let g:ycm_max_diagnostics_to_display = 30This option controls the key mappings used to select the first completion string. Invoking any of them repeatedly cycles forward through the completion list.
Some users like adding <Enter> to this list.
Default: ['<TAB>', '<Down>']
let g:ycm_key_list_select_completion = ['<TAB>', '<Down>']This option controls the key mappings used to select the previous completion string. Invoking any of them repeatedly cycles backwards through the completion list.
Note that one of the defaults is <S-TAB> which means Shift-TAB. That mapping
will probably only work in GUI Vim (Gvim or MacVim) and not in plain console Vim
because the terminal usually does not forward modifier key combinations to Vim.
Default: ['<S-TAB>', '<Up>']
let g:ycm_key_list_previous_completion = ['<S-TAB>', '<Up>']This option controls the key mapping used to invoke the completion menu for
semantic completion. By default, semantic completion is trigged automatically
after typing ., -> and :: in insert mode (if semantic completion support
has been compiled in). This key mapping can be used to trigger semantic
completion anywhere. Useful for searching for top-level functions and classes.
Console Vim (not Gvim or MacVim) passes <Nul> to Vim when the user types
<C-Space> so YCM will make sure that <Nul> is used in the map command when
you're editing in console Vim, and <C-Space> in GUI Vim. This means that you
can just press <C-Space> in both console and GUI Vim and YCM will do the right
thing.
Setting this option to an empty string will make sure no mapping is created.
Default: <C-Space>
let g:ycm_key_invoke_completion = '<C-Space>'This option controls the key mapping used to show the full diagnostic text when
the user's cursor is on the line with the diagnostic. It basically calls
:YcmShowDetailedDiagnostic.
Setting this option to an empty string will make sure no mapping is created.
Default: <leader>d
let g:ycm_key_detailed_diagnostics = '<leader>d'Normally, YCM searches for a .ycm_extra_conf.py file for compilation flags
(see the User Guide for more details on how this works). This option specifies
a fallback path to a config file which is used if no .ycm_extra_conf.py is
found.
You can place such a global file anywhere in your filesystem.
Default: ''
let g:ycm_global_ycm_extra_conf = ''When this option is set to 1 YCM will ask once per .ycm_extra_conf.py file
if it is safe to be loaded. This is to prevent execution of malicious code
from a .ycm_extra_conf.py file you didn't write.
To selectively get YCM to ask/not ask about loading certain .ycm_extra_conf.py
files, see the g:ycm_extra_conf_globlist option.
Default: 1
let g:ycm_confirm_extra_conf = 1This option is a list that may contain several globbing patterns. If a pattern
starts with a ! all .ycm_extra_conf.py files matching that pattern will be
blacklisted, that is they won't be loaded and no confirmation dialog will be
shown. If a pattern does not start with a ! all files matching that pattern
will be whitelisted. Note that this option is not used when confirmation is
disabled using g:ycm_confirm_extra_conf and that items earlier in the list
will take precedence over the later ones.
Rules:
*matches everything?matches any single character[seq]matches any character in seq[!seq]matches any char not in seq
Example:
let g:ycm_extra_conf_globlist = ['~/dev/*','!~/*']- The first rule will match everything contained in the
~/devdirectory so.ycm_extra_conf.pyfiles from there will be loaded. - The second rule will match everything in the home directory so a
.ycm_extra_conf.pyfile from there won't be loaded. - As the first rule takes precedence everything in the home directory excluding
the
~/devdirectory will be blacklisted.
NOTE: The glob pattern is first expanded with Python's os.path.expanduser()
and then resolved with os.path.abspath() before being matched against the
filename.
Default: []
let g:ycm_extra_conf_globlist = []By default, YCM's filepath completion will interpret relative paths like ../
as being relative to the folder of the file of the currently active buffer.
Setting this option will force YCM to always interpret relative paths as being
relative to Vim's current working directory.
Default: 0
let g:ycm_filepath_completion_use_working_dir = 0This option controls the character-based triggers for the various semantic completion engines. The option holds a dictionary of key-values, where the keys are Vim's filetype strings delimited by commas and values are lists of strings, where the strings are the triggers.
Setting key-value pairs on the dictionary adds semantic triggers to the internal default set (listed below). You cannot remove the default triggers, only add new ones.
A "trigger" is a sequence of one or more characters that trigger semantic
completion when typed. For instance, C++ (cpp filetype) has . listed as a
trigger. So when the user types foo., the semantic engine will trigger and
serve foo's list of member functions and variables. Since C++ also has ->
listed as a trigger, the same thing would happen when the user typed foo->.
It's also possible to use a regular expression as a trigger. You have to prefix
your trigger with re! to signify it's a regex trigger. For instance,
re!\w+\. would only trigger after the \w+\. regex matches.
NOTE: The regex syntax is NOT Vim's, it's Python's.
Default: [see next line]
let g:ycm_semantic_triggers = {
\ 'c' : ['->', '.'],
\ 'objc' : ['->', '.', 're!\[[_a-zA-Z]+\w*\s', 're!^\s*[^\W\d]\w*\s',
\ 're!\[.*\]\s'],
\ 'ocaml' : ['.', '#'],
\ 'cpp,objcpp' : ['->', '.', '::'],
\ 'perl' : ['->'],
\ 'php' : ['->', '::'],
\ 'cs,java,javascript,typescript,d,python,perl6,scala,vb,elixir,go' : ['.'],
\ 'ruby' : ['.', '::'],
\ 'lua' : ['.', ':'],
\ 'erlang' : [':'],
\ }Some omnicompletion engines do not work well with the YCM cache—in particular, they might not produce all possible results for a given prefix. By unsetting this option you can ensure that the omnicompletion engine is re-queried on every keypress. That will ensure all completions will be presented, but might cause stuttering and lagginess if the omnifunc is slow.
Default: 1
let g:ycm_cache_omnifunc = 1By default, YCM will query the UltiSnips plugin for possible completions of snippet triggers. This option can turn that behavior off.
Default: 1
let g:ycm_use_ultisnips_completer = 1Defines where GoTo* commands result should be opened.
Can take one of the following values:
[ 'same-buffer', 'horizontal-split', 'vertical-split', 'new-tab', 'new-or-existing-tab' ]
If this option is set to the 'same-buffer' but current buffer can not
be switched (when buffer is modified and nohidden option is set),
then result will be opened in horizontal split.
Default: 'same-buffer'
let g:ycm_goto_buffer_command = 'same-buffer'Defines the max size (in Kb) for a file to be considered for completion. If this option is set to 0 then no check is made on the size of the file you're opening.
Default: 1000
let g:ycm_disable_for_files_larger_than_kb = 1000YCM was rewritten to use a client-server architecture where most of the logic is
in the ycmd server. So the magic vim module you could have previously
imported in your .ycm_extra_conf.py files doesn't exist anymore.
To be fair, importing the magic vim module in extra conf files was never
supported in the first place; it only ever worked by accident and was never a
part of the extra conf API.
But fear not, you should be able to tweak your extra conf files to continue
working by using the g:ycm_extra_conf_vim_data option. See the docs on that
option for details.
That's a very rare Vim bug most users never encounter. It's fixed in Vim 7.4.72. Update to that version (or above) to resolve the issue.
If the warning is ld: warning: path '/usr/lib/libpython2.7.dylib' following -L not a directory, then feel free to ignore it; it's caused by a limitation of
CMake and is not an issue. Everything should still work fine.
This is Vim's preview window. Vim uses it to show you extra information about
something if such information is available. YCM provides Vim with such extra
information. For instance, when you select a function in the completion list,
the preview window will hold that function's prototype and the prototypes of
any overloads of the function. It will stay there after you select the
completion so that you can use the information about the parameters and their
types to write the function call.
If you would like this window to auto-close after you select a completion
string, set the g:ycm_autoclose_preview_window_after_completion option to 1
in your vimrc file. Similarly, the g:ycm_autoclose_preview_window_after_insertion
option can be set to close the preview window after leaving insert mode.
If you don't want this window to ever show up, add set completeopt-=preview to
your vimrc. Also make sure that the g:ycm_add_preview_to_completeopt option
is set to 0.
In Vim, run :messages and carefully read the output. YCM will echo messages to
the message log if it encounters problems. It's likely you misconfigured
something and YCM is complaining about it.
Also, you may want to run the :YcmDebugInfo command; it will make YCM spew out
various debugging information, including the ycmd logfile paths and the
compile flags for the current file if the file is a C-family language file and
you have compiled in Clang support. Logfiles can be automatically opened in the
editor using the :YcmToggleLogs command.
This means that libclang (which YCM uses for C-family semantic completion)
failed to pre-compile your file's preamble. In other words, there was an error
compiling some of the source code you pulled in through your header files. I
suggest calling the :YcmDiags command to see what they were.
Bottom line, if libclang can't pre-compile your file's preamble because there were errors in it, you're going to get slow completions because there's no AST cache.
This means you probably have some mappings that interfere with YCM's internal
ones. Make sure you don't have something mapped to <C-p>, <C-x> or <C-u>
(in insert mode).
YCM never selects something for you; it just shows you a menu and the user has to explicitly select something. If something is being selected automatically, this means there's a bug or a misconfiguration somewhere.
This means that YCM tried to set up a key mapping but failed because you already
had something mapped to that key combination. The <blah> part of the message
will tell you what was the key combination that failed.
Look in the Options section and see if any of the default mappings conflict with your own. Then change that option value to something else so that the conflict goes away.
Your system is too old for the precompiled binaries from llvm.org. Compile
Clang on your machine and then link against the libclang.so you just produced.
See the full installation guide for help.
Something (I don't know what) is wrong with the way that Homebrew configures and
builds Vim. I recommend using MacVim. Even if you don't like the MacVim GUI,
you can use the Vim binary that is inside the MacVim.app package (it's
MacVim.app/Contents/MacOS/Vim) and get the Vim console experience.
You should probably run brew rm python; brew install python to get the latest
fixes that should make YCM work with such a configuration. Also rebuild Macvim
then. If you still get problems with this, see issue #18 for
suggestions.
This was caused by a Vim bug. Update your version of Vim (Vim 7.3.874 is known to work, earlier versions may also fix this issue).
Look at the output of your CMake call. There should be a line in it like the
following (with .dylib in place of .so on a Mac):
-- Found PythonLibs: /usr/lib/libpython2.7.so (Required is at least version "2.5")
That would be the correct output. An example of incorrect output would be the following:
-- Found PythonLibs: /usr/lib/libpython2.7.so (found suitable version "2.5.1", minimum required is "2.5")
Notice how there's an extra bit of output there, the found suitable version "<version>" part, where <version> is not the same as the version of the
dynamic library. In the example shown, the library is version 2.7 but the second
string is version 2.5.1.
This means that CMake found one version of Python headers and a different version for the library. This is wrong. It can happen when you have multiple versions of Python installed on your machine.
You should probably add the following flags to your cmake call (again, dylib
instead of so on a Mac):
-DPYTHON_INCLUDE_DIR=/usr/include/python2.7 -DPYTHON_LIBRARY=/usr/lib/libpython2.7.so
This will force the paths to the Python include directory and the Python library to use. You may need to set these flags to something else, but you need to make sure you use the same version of Python that your Vim binary is built against, which is highly likely to be the system's default Python.
The error is usually encountered when compiling YCM on Centos or RHEL. The full error looks something like the following:
/usr/bin/ld: /usr/local/lib/libpython2.7.a(abstract.o): relocation R_X86_64_32 against `a local symbol' can not be used when making a shared object; recompile with -fPIC
It's possible to get a slightly different error that's similar to the one above. Here's the problem and how you solve it:
Your libpython2.7.a was not compiled with -fPIC so it can't be linked into
ycm_core.so. Use the -DPYTHON_LIBRARY= CMake flag to point it to a .so
version of libpython on your machine (for instance,
-DPYTHON_LIBRARY=/usr/lib/libpython2.7.so). Naturally, this means you'll have
to go through the full installation guide by hand.
This can happen on some Linux distros. If you encounter this situation, run Vim
under gdb. You'll probably see something like this in the output when Vim
crashes:
undefined symbol: clang_CompileCommands_dispose
This means that Vim is trying to load a libclang.so that is too old. You need
at least a 3.2 libclang. Some distros ship with a system libclang.so that
identifies itself as 3.2 but is not; it was cut from the upstream sources before
the official 3.2 release and some API changes (like the addition of the
CompileCommands API) were added after their cut.
So just go through the installation guide and make sure you are using a correct
libclang.so. I recommend downloading prebuilt binaries from llvm.org.
First, put let g:ycm_collect_identifiers_from_tags_files = 1 in your vimrc.
Make sure you are using Exuberant Ctags to produce your tags
files since the only supported tag format is the Exuberant Ctags
format. The format from "plain" ctags is NOT supported. The
output of ctags --version should list "Exuberant Ctags".
Ctags needs to be called with the --fields=+l (that's a lowercase L, not a
one) option because YCM needs the language:<lang> field in the tags output.
NOTE: Exuberant Ctags by default sets language tag for *.h
files as C++. If you have C (not C++) project, consider
giving parameter --langmap=c:.c.h to ctags to see tags from *.h files.
NOTE: Mac OS X comes with "plain" ctags installed by default. brew install ctags will get you the Exuberant Ctags version.
Also make sure that your Vim tags option is set correctly. See :h 'tags' for
details. If you want to see which tag files YCM will read for a given buffer,
run :echo tagfiles() with the relevant buffer active. Note that that function
will only list tag files that already exist.
YCM keeps you in a completefunc completion mode when you're typing in insert
mode and Vim disables <C-U> in completion mode as a "feature." Sadly there's
nothing I can do about this.
YCM comes with support for UltiSnips (snippet suggestions in the popup menu),
but you'll have to change the UltiSnips mappings. See :h UltiSnips-triggers in
Vim for details. You'll probably want to change some/all of the following
options:
g:UltiSnipsExpandTrigger
g:UltiSnipsJumpForwardTrigger
g:UltiSnipsJumpBackwardTriggerBecause of the identifier completion engine and subsequence-based filtering. Let's say you have many dozens of files open in a single Vim instance (I often do); the identifier-based engine then needs to store thousands (if not tens of thousands) of identifiers in its internal data-structures. When the user types, YCM needs to perform subsequence-based filtering on all of those identifiers (every single one!) in less than 10 milliseconds.
I'm sorry, but that level of performance is just plain impossible to achieve with VimScript. I've tried, and the language is just too slow. No, you can't get acceptable performance even if you limit yourself to just the identifiers in the current file and simple prefix-based filtering.
During YCM's development several show-stopper bugs were encountered in Vim.
Those needed to be fixed upstream (and were). A few months after those bugs were
fixed, Vim trunk landed the pyeval() function which improved YCM performance
even more since less time was spent serializing and deserializing data between
Vim and the embedded Python interpreter. A few critical bugfixes for pyeval()
landed in Vim 7.3.584 (and a few commits before that).
If you're referring to the User defined completion <bla bla> back at original
and similar, then just update to Vim 7.4.314 (or later) and they'll go away.
Use the delimitMate plugin instead. It does the same thing without conflicting with YCM.
If you have questions about the plugin or need help, please use the ycm-users mailing list, don't create issues on the tracker. The tracker is for bug reports and feature requests.
This can be a problem on virtual servers with limited memory. A possible
solution is to add more swap memory. A more practical solution would be to force
the build script to run only one compile job at a time. You can do this by
setting the YCM_CORES environment variable to 1. Example:
YCM_CORES=1 ./install.py --clang-completer
Never use Ctrl-C in Vim.
Using Ctrl-C to exit insert mode in Vim is a bad idea. The main issue here is
that Ctrl-C in Vim doesn't just leave insert mode, it leaves it without
triggering InsertLeave autocommands (as per Vim docs). This is a bad idea and
is likely to break many other things and not just YCM.
Bottom line, if you use Ctrl-C to exit insert mode in Vim, you're gonna have a
bad time.
If pressing <esc> is too annoying (agreed, it is), we suggest mapping it to
something more convenient. On a QWERTY keyboard, a good pick for the <esc> map
is inoremap jk <Esc>. This is right on the home row, it's an incredibly rare
digraph in English and if you ever need to type those two chars in sequence in
insert mode, you just type j, then wait 500ms, then type k.
Previously, YCM would send any diagnostics it would receive from the libclang semantic engine to Syntastic for display as signs in the gutter, red squiggles etc. Today, YCM uses its own code to do that.
Using Syntastic for this was always a kludge. Syntastic assumes its "checker" plugins behave in a certain way; those assumptions have never fit YCM. For instance, YCM continuously recompiles your code in the background for C-family languages and tries to push new diagnostics to the user as fast as possible, even while the user types.
Syntastic assumes that a checker only runs on file save ("active" mode) or even less frequently, when the user explicitly invokes it ("passive" mode). This mismatch in assumptions causes performance problems since Syntastic code isn't optimized for this use case of constant diagnostic refreshing.
Poor support for this use case also led to crash bugs in Vim caused by Syntastic-Vim interactions (issue #593) and other problems, like random Vim flickering. Attempts were made to resolve these issues in Syntastic, but ultimately some of them failed (for various reasons).
Implementing diagnostic display code directly in YCM resolves all of these problems. Performance also improved substantially since the relevant code is now written in Python instead of VimScript (which is very slow) and is tailored only for YCM's use-cases. We were also able to introduce new features in this area since we're now not limited to the Syntastic checker API.
We've tried to implement this in the most backwards-compatible way possible; YCM options that control diagnostic display fall back to Syntastic options that control the same concepts if the user has those set.
Still, some Syntastic-specific configuration you might have had might not be supported by the new code. Please file issues on the tracker in such cases; if we find the request to be reasonable, we'll find a way to address it.
This is caused by an issue with libclang that only affects some operating
systems. Compiling with clang the binary will use the correct default header
search paths but compiling with libclang.so (which YCM uses) does not.
Mac OS X is normally affected, but there's a workaround in YCM for that specific OS. If you're not running that OS but still have the same problem, continue reading.
The workaround is to call echo | clang -v -E -x c++ - and look at the
paths under the #include <...> search starts here: heading. You should take
those paths, prepend -isystem to each individual path and append them all to
the list of flags you return from your FlagsForFile function in your
.ycm_extra_conf.py file.
See issue #303 for details.
Install YCM with NeoBundle
NeoBundle can do the compilation for you; just add the following to your vimrc:
NeoBundle 'Valloric/YouCompleteMe', {
\ 'build' : {
\ 'mac' : './install.py',
\ 'unix' : './install.py',
\ 'windows' : 'install.py',
\ 'cygwin' : './install.py'
\ }
\ }But you could have problems with the time needed to get the sub modules and compile the whole thing. To increase the Neobundle timeout to 1500 seconds, add the following to your vimrc:
let g:neobundle#install_process_timeout = 1500Take a look at the instructions for using the JavaScript completer.
If this is still really annoying, and you have a good reason not to have a
.tern-project file, create an empty .tern-config file in your home directory
and YCM will stop complaining.
If you have questions about the plugin or need help, please use the ycm-users mailing list.
If you have bug reports or feature suggestions, please use the issue tracker.
The latest version of the plugin is available at http://valloric.github.io/YouCompleteMe/.
The author's homepage is http://val.markovic.io.
This software is licensed under the GPL v3 license. © 2015 YouCompleteMe contributors
