Add ocaml-language-server for OCaml and ReasonML

autoload/ale/handlers/ols.vim

@@ -0,0 +1,25 @@
+" Author: Michael Jungo <michaeljungo92@gmail.com>
+" Description: Handlers for the OCaml language server
+
+function! ale#handlers#ols#GetExecutable(buffer) abort
+    let l:ols_setting = ale#handlers#ols#GetLanguage(a:buffer) . '_ols'
+    return ale#node#FindExecutable(a:buffer, l:ols_setting, [
+    \   'node_modules/.bin/ocaml-language-server',
+    \])
+endfunction
+
+function! ale#handlers#ols#GetCommand(buffer) abort
+    let l:executable = ale#handlers#ols#GetExecutable(a:buffer)
+
+    return ale#node#Executable(a:buffer, l:executable) . ' --stdio'
+endfunction
+
+function! ale#handlers#ols#GetLanguage(buffer) abort
+    return getbufvar(a:buffer, '&filetype')
+endfunction
+
+function! ale#handlers#ols#GetProjectRoot(buffer) abort
+    let l:merlin_file = ale#path#FindNearestFile(a:buffer, '.merlin')
+
+    return !empty(l:merlin_file) ? fnamemodify(l:merlin_file, ':h') : ''
+endfunction