Update lang#c layer (#3899)

autoload/SpaceVim/commands.vim

@@ -19,7 +19,8 @@ function! SpaceVim#commands#load() abort
   ""
   " Set or check SpaceVim option. {opt} should be the option name of
   " spacevim, This command will use [value] as the value of option name.
-  command! -nargs=+ SPSet call SpaceVim#options#set(<f-args>)
+  command! -nargs=+ -complete=custom,SpaceVim#commands#complete_options
+        \ SPSet call SpaceVim#options#set(<f-args>)
   ""
   " print the debug information of spacevim, [!] forces the output into a
   " new buffer.
@@ -296,5 +297,9 @@ function! s:SHA() abort
   return '-' . sha
 endfunction
 
+function! SpaceVim#commands#complete_options(...)
+  return join(map(getcompletion('g:spacevim_','var'), 'v:val[11:]'), "\n")
+endfunction
+
 
 " vim:set et sw=2 cc=80:

autoload/SpaceVim/layers/lang/c.vim

@@ -119,7 +119,7 @@ function! SpaceVim#layers#lang#c#plugins() abort
     elseif g:spacevim_autocomplete_method ==# 'asyncomplete'
       call add(plugins, ['wsdjeg/asyncomplete-clang.vim', {'merged' : 0, 'loadconf' : 1}])
     else
-      call add(plugins, ['Rip-Rip/clang_complete'])
+      call add(plugins, ['Rip-Rip/clang_complete', {'if' : s:CPT.has('python') || s:CPT.has('python3')}])
     endif
   endif
 

docs/_posts/2019-05-10-use-vim-as-a-c-cpp-ide.md

@@ -56,6 +56,13 @@ This option requires `+python` or `+python3` enabled and `libclang` has been ins
 By default the autocomplete layer has been enabled, so after loading `lang#c` layer, the code completion
 for C/C++ language should works well.
 
+If the `autocomplete_method` is `deoplete`, then `Shougo/deoplete-clangx` will be loaded in `lang#c` layer.
+
+If the `autocomplete_method` is `asyncomplete`, then `wsdjeg/asyncomplete-clang.vim` will be loaded.
+
+If the `autocomplete_method` is `neocomplete`, Then `Rip-Rip/clang_complete` will be loaded.
+
+You can check the value of `autocomplete_method` via `:SPSet autocomplete_method`.
 
 ### alternate file jumping