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spacemacs/layers/+tools/ycmd
syl20bnr ebe4c60264 Revert "Defer packages by default using use-package-always-defer"
This reverts commit 29c78ce841 and all other fixes
that have been made afterwards.

The motivation is that use-package is seen by many as a replacement for
`require`. Is use-package always defer the loading of packages then is breaks
this use case, this does not respect POLA so even if it was making Spacemacs
loading faster (up to 3s faster on some startup on my machine) we just cannot
use it, it would be irresponsible. Spacemacs should be easy to use, loading
performance will come with time but it is not a priority.
2018-03-03 23:40:10 -05:00
..
funcs.el Happy New Year 2018! 2018-01-04 02:00:25 -05:00
global_conf.py fix: ycmd don't search for compilation DB in subfolders 2018-02-17 16:09:06 -05:00
packages.el Revert "Defer packages by default using use-package-always-defer" 2018-03-03 23:40:10 -05:00
README.org add features list to the ycmd layer readme 2018-01-27 16:58:06 +02:00

YCMD layer

Description

This layer adds emacs-ycmd support.

Features:

  • YouCompleteMe based code-completion
  • Integrations with company, flycheck, and eldoc

Install

Layer

To use this configuration layer, add it to your ~/.spacemacs. You will need to add ycmd to the existing dotspacemacs-configuration-layers list in this file.

YCMD

  1. Install the ycm server. Installation instructions can be found here.
  2. Set the ycmd-server-command variable to reflect the path to the installation:

    (setq ycmd-server-command '("python" "/path/to/YouCompleteMe/third_party/ycmd/ycmd"))

    Note that no filename expansions are done, so ~-paths will not work out of the box. If you need expansions, you can use Emacs's file-truename like this:

    (setq ycmd-server-command (list "python" (file-truename "~/some/path")))
  3. By default, spacemacs configures ycmd for getting the compilation flags from either a compile_commands.json or a .clang_complete file and get additionnal flags from a .ycm_extra_flags file. If you do not like this behaviour, you can write your own .ycm_extra_conf.py file. See Configuration for more details.
  4. Whitelist the file by adding the following to .spacemacs:

    ;; In this example we whitelist everything in the Develop folder
    (setq ycmd-extra-conf-whitelist '("~/Develop/*"))
  5. The completion is not going to work automatically until we actually force it:

    (setq ycmd-force-semantic-completion t)

Other Requirements

This package requires the auto-completion layer in order to get actual completion. The syntax-checking layer is required for flycheck support.

Configuration

Activating ycmd in a major mode

By default this layer only activates ycmd for c++-mode and c-mode.

If you want ycmd support in other modes you might just want to add it for specific languages like:

(add-hook 'c++-mode-hook 'ycmd-mode)

Getting the compilation flags

Spacemacs uses its own ycmd global configuration file. If you prefer, you can write your own .ycm_extra_conf.py.

Spacemacs will search for a compile_command.json or fall back to a .clang_complete file in all parent directories of the current translation unit. Spacemacs will try to make up for missing files in the compile_commands.json using heuristics described in global_conf.py.

The user can provide additionnal flags by writing a .ycm_extra_flags in any parent directory of the current translation unit. This is particularly useful when cross-compiling.

Example .ycm_extra_flags:

# Additionnal flags for ycmd
--sysroot="/path/to/your/toolchain/libc" # if you are cross-compiling

If your build system doesn't handle the creation of a compile_commands.json, you can use tools such as Bear or scan-build to generate it, which both work with almost any build system.

Functions

If company-ycmd is used, then a function ycmd/manual-semantic-company-completer is defined. This function is useful if you want to get semantic completions only when you press a keybinding; in larger projects ycmd may not be performant for as-you-type auto-completion to work well. You can bind it like so:

(global-set-key (kbd "<C-tab>") 'ycmd/manual-semantic-company-completer)

This function will automatically cancel out of any active completers, and offer semantic completions. It will automatically make an exception when you are completing includes; these do not count as semantic completion so the exception is necessary for the keybinding to work when completing includes.

Key Bindings

Adds SPC m g g go to definition binding to c++-mode as well as SPC m g G for the more imprecise but faster version.