fix textDocumentSync.save ServerCapability check

The ServerCapability textDocumentSync is optional and may be of kind
TextDocumentSyncOptions | TextDocumentSyncKind;

If a server uses TextDocumentSyncKind which is a integer enum
our .save check fails.
Test if it is save to use textDocumentSync as table before checking the
save capability.

Fixes !35.

1 files changed, 2 insertions, 1 deletions

diff --git a/init.lua b/init.lua
index c6bbb02..b0339aa 100644
--- a/init.lua
+++ b/init.lua
@@ -1054,7 +1054,8 @@ local function lspc_open(ls, win, file)
   end)
 
   -- the server is interested in didSave notifications
-  if ls.capabilities.textDocumentSync.save then
+  if ls.capabilities.textDocumentSync and type(ls.capabilities.textDocumentSync) ==
+      'table' and ls.capabilities.textDocumentSync.save then
     vis.events.subscribe(vis.events.FILE_SAVE_POST,
                          function(file, path) -- luacheck: ignore file
       for _, ls in pairs(lspc.running) do -- luacheck: ignore ls