119 lines
4.7 KiB
Org Mode
119 lines
4.7 KiB
Org Mode
#+TITLE: YCMD layer
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* Table of Contents :TOC_4_gh:noexport:
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- [[#description][Description]]
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- [[#features][Features:]]
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- [[#install][Install]]
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- [[#layer][Layer]]
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- [[#ycmd][YCMD]]
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- [[#other-requirements][Other Requirements]]
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- [[#configuration][Configuration]]
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- [[#activating-ycmd-in-a-major-mode][Activating ycmd in a major mode]]
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- [[#getting-the-compilation-flags][Getting the compilation flags]]
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- [[#functions][Functions]]
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- [[#key-bindings][Key Bindings]]
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* Description
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This layer adds [[https://github.com/abingham/emacs-ycmd][emacs-ycmd]] support.
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** Features:
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- [[https://github.com/Valloric/YouCompleteMe][YouCompleteMe]] based code-completion
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- Integrations with company, flycheck, and eldoc
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* Install
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** Layer
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To use this configuration layer, add it to your =~/.spacemacs=. You will need to
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add =ycmd= to the existing =dotspacemacs-configuration-layers= list in this
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file.
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** YCMD
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1) Install the =ycm= server. Installation instructions can be found [[https://github.com/Valloric/ycmd#user-content-building][here]].
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2) Set the =ycmd-server-command= variable to reflect the path to the installation:
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#+BEGIN_SRC emacs-lisp
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(setq ycmd-server-command '("python" "/path/to/YouCompleteMe/third_party/ycmd/ycmd"))
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#+END_SRC
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Note that no filename expansions are done, so =~= -paths will not work out of the box.
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If you need expansions, you can use Emacs’s =file-truename= like this:
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#+BEGIN_SRC emacs-lisp
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(setq ycmd-server-command (list "python" (file-truename "~/some/path")))
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#+END_SRC
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3) By default, spacemacs configures ycmd for getting the compilation flags from either
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a compile_commands.json or a .clang_complete file and get additionnal flags from a
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.ycm_extra_flags file. If you do not like this behaviour, you can write your own
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[[https://github.com/Valloric/YouCompleteMe/blob/master/README.md#c-family-semantic-completion][.ycm_extra_conf.py file]]. See [[#configuration][Configuration]] for more details.
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4) Whitelist the file by adding the following to =.spacemacs=:
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#+BEGIN_SRC emacs-lisp
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;; In this example we whitelist everything in the Develop folder
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(setq ycmd-extra-conf-whitelist '("~/Develop/*"))
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#+END_SRC
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5) The completion is not going to work automatically until we actually force it:
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#+BEGIN_SRC emacs-lisp
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(setq ycmd-force-semantic-completion t)
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#+END_SRC
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** Other Requirements
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This package requires the =auto-completion= layer in order to get actual
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completion. The =syntax-checking= layer is required for flycheck support.
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* Configuration
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** Activating ycmd in a major mode
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By default this layer only activates ycmd for =c++-mode= and =c-mode=.
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If you want ycmd support in other modes you might just want to add it for
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specific languages like:
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#+BEGIN_SRC emacs-lisp
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(add-hook 'c++-mode-hook 'ycmd-mode)
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#+END_SRC
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** Getting the compilation flags
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Spacemacs uses its own ycmd global configuration file. If you prefer, you can
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write your own [[https://github.com/Valloric/YouCompleteMe/blob/master/README.md#user-content-c-family-semantic-completion][.ycm_extra_conf.py]].
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Spacemacs will search for a compile_command.json or fall back to a
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.clang_complete file in all parent directories of the current translation unit.
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Spacemacs will try to make up for missing files in the compile_commands.json
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using heuristics described in global_conf.py.
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The user can provide additionnal flags by writing a .ycm_extra_flags in any
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parent directory of the current translation unit. This is particularly useful
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when cross-compiling.
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Example .ycm_extra_flags:
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#+BEGIN_SRC conf
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# Additionnal flags for ycmd
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--sysroot="/path/to/your/toolchain/libc" # if you are cross-compiling
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#+END_SRC
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If your build system doesn’t handle the creation of a compile_commands.json,
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you can use tools such as [[https://github.com/rizsotto/Bear][Bear]] or [[https://pypi.python.org/pypi/scan-build][scan-build]] to generate it, which both work
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with almost any build system.
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* Functions
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If ~company-ycmd~ is used, then a function
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~ycmd/manual-semantic-company-completer~ is defined. This function is
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useful if you want to get semantic completions only when you press a
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keybinding; in larger projects ycmd may not be performant for as-you-type
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auto-completion to work well. You can bind it like so:
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#+BEGIN_SRC emacs-lisp
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(global-set-key (kbd "<C-tab>") 'ycmd/manual-semantic-company-completer)
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#+END_SRC
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This function will automatically cancel out of any active completers, and offer
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semantic completions. It will automatically make an exception when you are
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completing includes; these do not count as semantic completion so the exception
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is necessary for the keybinding to work when completing includes.
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* Key Bindings
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Adds ~SPC m g g~ go to definition binding to =c++-mode= as well as ~SPC m g G~
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for the more imprecise but faster version.
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