extra: nvim: Add nvim-treesitter plugin

Signed-off-by: Christoph Heiss <christoph@c8h4.io>

extra/nvim/lua/plugins.lua

@@ -299,6 +299,8 @@ require('lazy').setup({
       vim.opt.shortmess:append('c')
     end,
   },
+
+  { 'nvim-treesitter/nvim-treesitter', build = ':TSUpdate' },
 })
 
 -- Basic things first
@@ -311,3 +313,12 @@ vim.cmd.highlight('comment', 'ctermfg=7')
 -- Bring modified buffers to attention
 vim.cmd['highlight!']('BufferInactiveMod', 'cterm=bold')
 vim.cmd['highlight!']('BufferCurrentMod', 'cterm=bold')
+
+-- Install wanted treesitter parsers
+local ts_parsers = require('nvim-treesitter.parsers')
+local ts_install = require('nvim-treesitter.install')
+for _, p in ipairs(utils.WANTED_TREESITTER_PARSERS) do
+  if not ts_parsers.has_parser(p) then
+    ts_install.update(p)
+  end
+end

extra/nvim/lua/utils.lua

@@ -19,4 +19,9 @@ return {
     '*/node_modules/*',
     '*/tmp/*',
   },
+  WANTED_TREESITTER_PARSERS = {
+    'lua',
+    'haskell',
+    'rust',
+  },
 }