nvim: Move to treesitter and lspsaga

Added lspsaga to enhance some of the lsp actions I can do - mappings are
mostly the same as before, pretty much all lsp actions can be invoked by
g<mnemonic> (e.g. `gr` for rename, `gh` for symbol help, `gd` for go
definition, `K` for help hover, `gc` for code completion and some more).
`[e` and `]e` move between lsp diagnostic errors.

Switched out many syntax highlighting plugins for treesitter, which is
an experiment for now, but I would love to keep it like this if it works
out.

nvim/.config/nvim/lua/_treesitter.lua

@@ -0,0 +1,8 @@
+require'nvim-treesitter.configs'.setup {
+    -- one of "all", "maintained" (parsers with maintainers), or a list of languages
+    ensure_installed = "maintained",
+    highlight = { enable = true },
+    incremental_selection = { enable = true },
+    textobjects = { enable = true },
+    indent = { enable = true },
+}

nvim/.config/nvim/lua/nvim-lspconfig/init.lua

@@ -1,27 +1,62 @@
-local on_attach = function(client, bufnr)
+local saga = require 'lspsaga'
+
+
+local on_attach = function(_, _)
     -- Keybindings for LSPs
     -- Note these are in on_attach so that they don't override bindings in a non-LSP setting
-    vim.fn.nvim_set_keymap("n", "gd", "<cmd>lua vim.lsp.buf.definition()<CR>",
+    vim.api.nvim_set_keymap("n", "gh", "<cmd>lua require 'lspsaga.provider'.lsp_finder()<CR>",
                            {noremap = true, silent = true})
-    vim.fn.nvim_set_keymap("n", "gD",
+    vim.api.nvim_set_keymap("n", "gd", "<cmd>lua require'lspsaga.provider'.preview_definition()<CR>",
-                           "<cmd>lua vim.lsp.buf.implementation()<CR>",
                            {noremap = true, silent = true})
-    vim.fn.nvim_set_keymap("n", "K", "<cmd>lua vim.lsp.buf.hover()<CR>",
+    vim.api.nvim_set_keymap("n", "gc", "<cmd>lua require 'lspsaga.codeaction'.code_action()<CR>",
                            {noremap = true, silent = true})
-    vim.fn.nvim_set_keymap("n", "gK",
+    vim.api.nvim_set_keymap("v", "gc", "<cmd>'<,'>lua require 'lspsaga.codeaction'.range_code_action()<CR>",
-                           "<cmd>lua vim.lsp.buf.signature_help()<CR>",
                            {noremap = true, silent = true})
-    vim.fn.nvim_set_keymap("n", "1gD",
+    vim.api.nvim_set_keymap("n", "K", "<cmd>lua require('lspsaga.hover').render_hover_doc()<CR>",
-                           "<cmd>lua vim.lsp.buf.type_definition()<CR>",
                            {noremap = true, silent = true})
-    vim.fn.nvim_set_keymap("n", "gr", "<cmd>lua vim.lsp.buf.references()<CR>",
+    vim.api.nvim_set_keymap("n", "gK", "<cmd>lua require('lspsaga.signaturehelp').signature_help()<CR>",
                            {noremap = true, silent = true})
-    vim.fn.nvim_set_keymap("n", "g0",
+    vim.api.nvim_set_keymap("n", "gr", "<cmd>lua require('lspsaga.rename').rename()<CR>",
-                           "<cmd>lua vim.lsp.buf.document_symbol()<CR>",
                            {noremap = true, silent = true})
-    vim.fn.nvim_set_keymap("n", "gW",
+
-                           "<cmd>lua vim.lsp.buf.workspace_symbol()<CR>",
+    vim.api.nvim_set_keymap("n", "ge", "<cmd>lua require('lspsaga.diagnostic').show_line_diagnostics()<CR>",
                            {noremap = true, silent = true})
+    vim.api.nvim_set_keymap("n", "[e", "<cmd>lua require('lspsaga.diagnostic').lsp_jump_diagnostic_next()<CR>",
+                           {noremap = true, silent = true})
+    vim.api.nvim_set_keymap("n", "]e", "<cmd>lua require('lspsaga.diagnostic').lsp_jump_diagnostic_prev()<CR>",
+                           {noremap = true, silent = true})
+
+    vim.api.nvim_set_keymap("n", "C-f", "<cmd>lua require('lspsaga.action').smart_scroll_with_saga(1)<CR>",
+                           {noremap = true, silent = true})
+    vim.api.nvim_set_keymap("n", "C-b", "<cmd>lua require('lspsaga.action').smart_scroll_with_saga(-1)<CR>",
+                           {noremap = true, silent = true})
+
+    require("lspsaga").init_lsp_saga {
+				error_sign = 'X',
+				warn_sign = '⚠️',
+				hint_sign = '⚡',
+				infor_sign = 'ℹ️',
+				code_action_icon = '💡',
+				finder_definition_icon = '📖 ',
+				finder_reference_icon = '🔖 ',
+				finder_action_keys = {
+					open = '<cr>',
+					split = 's',
+					vsplit = 'v',
+					quit = '<esc>',
+					scroll_down = '<c-f>',
+					scroll_up = '<c-b>'
+				},
+				code_action_keys = {
+					quit = '<esc>',
+					exec = '<cr>'
+				},
+				rename_action_keys = {
+					quit = '<esc>',
+					exec = '<cr>'
+				},
+				definition_preview_icon = '📖 '
+			}
 end
 
 require'lspconfig'.pyls.setup {on_attach = on_attach}
@@ -30,7 +65,7 @@ require'lspconfig'.bashls.setup {on_attach = on_attach}
 require'lspconfig'.gopls.setup {on_attach = on_attach}
 require'lspconfig'.texlab.setup {on_attach = on_attach}
 
--- requires the lua-language-server package to be installed 
+-- requires the lua-language-server package to be installed
 -- The arch package defaults to the following directory
 local sumneko_root_path = "/usr/share/lua-language-server"
 require'lspconfig'.sumneko_lua.setup {
@@ -58,3 +93,4 @@ require'lspconfig'.sumneko_lua.setup {
   },
   on_attach = on_attach,
 }
+saga.init_lsp_saga()

nvim/.config/nvim/plugin/completion-nvim.vim

@@ -64,7 +64,7 @@ let g:completion_chain_complete_list = {
       \    { 'mode': '<c-n>'}
       \],
       \ 'default': [
-      \    { 'complete_items': [ 'lsp', 'snippet' ]},
+      \    { 'complete_items': [ 'ts', 'lsp', 'snippet' ]},
       \    { 'complete_items': [ 'buffers' ] },
       \    { 'complete_items': [ 'path' ], 'triggered_only': ['/'] },
       \    { 'mode': '<c-p>'},

nvim/.config/nvim/plugins.vim

@@ -40,10 +40,17 @@ Plug 'junegunn/vim-peekaboo'
 Plug 'junegunn/fzf', { 'dir': '~/.fzf', 'do': './install --bin' }
 Plug 'junegunn/fzf.vim'
 
+                                                                                      " neovim goodies: treesitter and lsp
 Plug 'neovim/nvim-lspconfig'                                                          " some commong language server configurations
 Plug 'glepnir/lspsaga.nvim'                                                           " nice and fast ui for lsp actions
+
 Plug 'nvim-lua/completion-nvim'                                                       " simple completion engine built specifically for nvim and lsp
 Plug 'steelsojka/completion-buffers'                                                  " completion source from words found in current buffers
+
+Plug 'nvim-treesitter/nvim-treesitter', {'do': ':TSUpdate'}
+Plug 'nvim-treesitter/completion-treesitter'
+
+
 Plug 'desmap/ale-sensible' | Plug 'w0rp/ale'                                          " asynchronous linting - might be superseded by lsp or coc.nvim at some point
                                                                                       " statusline
 Plug 'vim-airline/vim-airline'
@@ -71,12 +78,6 @@ Plug 'junegunn/goyo.vim', { 'for': ['pandoc', 'markdown', 'txt'], 'on': 'Goyo' }
 Plug 'junegunn/limelight.vim', { 'for': ['pandoc', 'markdown', 'txt'], 'on': 'Goyo' } " provide even distraction free-er writing (lowlight paragraphs)
                                                                                       " Language Integration
 Plug 'euclidianAce/BetterLua.vim'                                                     " better syntax highlighting for lua
-Plug 'sheerun/vim-polyglot'                                                           " syntax plugins for almost every language
-Plug 'stephpy/vim-yaml'
-Plug 'mhartington/nvim-typescript', {'for': 'typescript','do': './install.sh'}
-
-Plug 'fatih/vim-go', { 'do': ':GoUpdateBinaries' }
-Plug 'aliou/bats.vim'
 
 if !has('nvim')
   Plug 'tpope/vim-sensible'