Add TSUpdate command to update parsers

doc/nvim-treesitter.txt

@@ -127,6 +127,11 @@ You can use |:TSInstall| `all` to install all parsers.
 :TSInstallInfo~
 
 List informations about currently installed parsers
+							           *:TSUpdate*
+:TSUpdate {language}~
+
+Update the installed parser of {language} or all installed parsers
+if {language} is omitted.
 
 								*:TSBufEnable*
 :TSBufEnable {module}~

lua/nvim-treesitter/info.lua

@@ -76,6 +76,16 @@ local function module_info(mod)
   end
 end
 
+function M.installed_parsers()
+  local installed = {}
+  for _, p in pairs(parsers.available_parsers()) do
+    if parsers.has_parser(p) then
+      table.insert(installed, p)
+    end
+  end
+  return installed
+end
+
 M.commands = {
   TSInstallInfo = {
     run = install_info,

lua/nvim-treesitter/install.lua

@@ -4,6 +4,7 @@ local luv = vim.loop
 
 local utils = require'nvim-treesitter.utils'
 local parsers = require'nvim-treesitter.parsers'
+local info = require'nvim-treesitter.info'
 
 local M = {}
 
@@ -122,11 +123,13 @@ end
 
 local function install_lang(lang, ask_reinstall, cache_folder, package_path, with_sync)
   if #api.nvim_get_runtime_file('parser/'..lang..'.so', false) > 0 then
-    if not ask_reinstall then return end
+    if ask_reinstall ~= 'force' then
+      if not ask_reinstall then return end
 
-    local yesno = fn.input(lang .. ' parser already available: would you like to reinstall ? y/n: ')
-    print('\n ') -- mandatory to avoid messing up command line
-    if not string.match(yesno, '^y.*') then return end
+      local yesno = fn.input(lang .. ' parser already available: would you like to reinstall ? y/n: ')
+      print('\n ') -- mandatory to avoid messing up command line
+      if not string.match(yesno, '^y.*') then return end
+    end
   end
 
   local parser_config = parsers.get_parser_configs()[lang]
@@ -176,6 +179,17 @@ local function install(with_sync, ask_reinstall)
   end
 end
 
+function M.update(lang)
+  if lang then
+    install(false, 'force')(lang)
+  else
+    local installed = info.installed_parsers()
+    for _, lang in pairs(installed) do
+      install(false, 'force')(lang)
+    end
+  end
+end
+
 M.ensure_installed = install(false, false)
 
 M.commands = {
@@ -192,6 +206,13 @@ M.commands = {
       "-nargs=+",
       "-complete=custom,v:lua.ts_installable_parsers"
     }
+  },
+  TSUpdate = {
+    run = M.update,
+    args = {
+      "-nargs=*",
+      "-complete=custom,v:lua.ts_installed_parsers"
+    }
   }
 }
 

plugin/nvim-treesitter.vim

@@ -13,6 +13,9 @@ lua << EOF
 ts_installable_parsers = function()
   return table.concat(require'nvim-treesitter.parsers'.available_parsers(), '\n')
 end
+ts_installed_parsers = function()
+  return table.concat(require'nvim-treesitter.info'.installed_parsers(), '\n')
+end
 ts_available_modules = function()
   return table.concat(require'nvim-treesitter.configs'.available_modules(), '\n')
 end