Add option to disable autocomplete

Fixes natebosch#15

- Add a global variable to configure autocomplete behavior.
- When autocomplete is disabled store suggestions in a buffer local
  variable instead of popping open the completion menu.
- Add a function which can serve as a `completefunc` reading from the
  stored suggestions.
- Update the README with new configuration option.

CHANGELOG.md

@@ -4,6 +4,7 @@
   - Bug fix: Don't leave an extra character when completing after typing 3
     characters.
   - Filter completions after typing 3 characters.
+  - Add configuration to disable autocomplete.
 
 # 0.2.1
 

README.md

@@ -30,6 +30,13 @@ nnoremap gd :LSClientGoToDefinition<CR>
 nnoremap gr :LSClientFindReferences<CR>
 ```
 
+To disable autocomplete in favor of manual completion also add
+
+```viml
+let g:lsc_enable_autocomplete = v:false
+set completefunc=lsc#complete#complete
+```
+
 ## Features
 
 The protocol does not require that every language server supports every feature
@@ -65,6 +72,10 @@ the documentation window use the following:
 autocmd CompleteDone * silent! pclose
 ```
 
+Disable autocomplete with `let g:lsc_enable_autocomplete = v:false`. When using
+manual completion the `completefunc` may have no results if completion is
+requested before the server responds with suggestions.
+
 ### Jump to definition
 
 While the cursor is on any identifier call `LSClientGoToDefinition` to jump to

autoload/lsc/complete.vim

@@ -61,6 +61,7 @@ endfunction
 augroup LscCompletion
   autocmd!
   autocmd CompleteDone * let b:lsc_is_completing = v:false
+      \ | silent! unlet b:lsc_completion
 augroup END
 
 " TODO: Make this customizable
@@ -96,10 +97,14 @@ function! s:startCompletion() abort
   let data = {'old_pos': getcurpos(),
       \ 'completion_id': s:completion_id,
       \ 'filetype': &filetype}
-  function data.trigger(completions)
+  function data.trigger(completion)
     call s:MarkNotCompleting(self.filetype)
     if s:isCompletionValid(self.old_pos, self.completion_id)
-      call s:SuggestCompletions(a:completions)
+      if (g:lsc_enable_autocomplete)
+        call s:SuggestCompletions(a:completion)
+      else
+        let b:lsc_completion = a:completion
+      endif
     else
       let b:lsc_is_completing = v:false
     endif
@@ -120,6 +125,16 @@ function! s:SuggestCompletions(completion) abort
   call complete(start, suggestions)
 endfunction
 
+function! lsc#complete#complete(findstart, base) abort
+  if !exists('b:lsc_completion') | return -1 | endif
+  if a:findstart
+    if len(b:lsc_completion.items) == 0 | return -3 | endif
+    return  s:FindStart(b:lsc_completion) - 1
+  else
+    return s:FindSuggestions(a:base, b:lsc_completion)
+  endif
+endfunction
+
 function! s:FindStart(completion) abort
   if has_key(a:completion, 'start_col')
     return a:completion.start_col

plugin/lsc.vim

@@ -7,6 +7,9 @@
 if !exists('g:lsc_server_commands')
   let g:lsc_server_commands = {}
 endif
+if !exists('g:lsc_enable_autocomplete')
+  let g:lsc_enable_autocomplete = v:true
+endif
 
 command! LSClientGoToDefinition call lsc#reference#goToDefinition()
 command! LSClientFindReferences call lsc#reference#findReferences()