Add cmp and vsnip

flake.lock

@@ -20,6 +20,22 @@
         "type": "github"
       }
     },
+    "cmp-git": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1659918460,
+        "narHash": "sha256-/fHoZxtJFG9v1sw/rQU2fa0ybO7bIovvRvY6M/mU5sc=",
+        "owner": "petertriho",
+        "repo": "cmp-git",
+        "rev": "fae6cdb407ad6c63a0b1928670bad1a67a55b887",
+        "type": "github"
+      },
+      "original": {
+        "owner": "petertriho",
+        "repo": "cmp-git",
+        "type": "github"
+      }
+    },
     "home-manager": {
       "inputs": {
         "nixpkgs": [
@@ -91,6 +107,7 @@
     "root": {
       "inputs": {
         "agenix": "agenix",
+        "cmp-git": "cmp-git",
         "home-manager": "home-manager",
         "impermanence": "impermanence",
         "lsp-trouble": "lsp-trouble",

flake.nix

@@ -8,6 +8,11 @@
       inputs.nixpkgs.follows = "nixpkgs";
     };
 
+    cmp-git = {
+      url = "github:petertriho/cmp-git";
+      flake = false;
+    };
+
     home-manager = {
       url = "github:nix-community/home-manager/release-22.05";
       inputs.nixpkgs.follows = "nixpkgs";

programs/nvim.nix

@@ -8,7 +8,6 @@
       EDITOR = "nvim";
     };
 
-    # TODO: completion
     programs.neovim = let
       leader = ",";
     in {
@@ -20,11 +19,22 @@
             src = inputs."${name}";
           };
         buildPlugins = names: lib.attrsets.genAttrs names buildPlugin;
-        plugins = buildPlugins ["lsp-trouble"];
+        plugins = buildPlugins [
+          "cmp-git"
+          "lsp-trouble"
+        ];
       in
         with pkgs.vimPlugins;
         with plugins; [
+          {plugin = cmp-buffer;}
+          {plugin = cmp-calc;}
+          {plugin = cmp-latex-symbols;}
+          {plugin = cmp-nvim-lsp;}
+          {plugin = cmp-path;}
+          {plugin = cmp-treesitter;}
+          {plugin = cmp-vsnip;}
           {plugin = editorconfig-nvim;}
+          {plugin = friendly-snippets;}
           {plugin = fugitive;}
           {plugin = lsp-trouble;}
           {plugin = rust-vim;}
@@ -32,6 +42,11 @@
           {plugin = vim-nix;}
           {plugin = vim-repeat;}
 
+          {
+            plugin = cmp-git;
+            config = "lua require 'cmp_git'.setup()";
+          }
+
           {
             plugin = crates-nvim;
             config = ''
@@ -100,16 +115,70 @@
             config = "lua require 'nvim-autopairs'.setup {}";
           }
 
+          {
+            plugin = nvim-cmp;
+            config = ''
+              set completeopt=menu,menuone,noselect
+
+              lua <<EOF
+                local cmp = require 'cmp'
+
+                cmp.setup {
+                  snippet = {
+                    expand = function(args)
+                      vim.fn["vsnip#anonymous"](args.body)
+                    end,
+                  },
+                  window = {
+                    completion = cmp.config.window.bordered(),
+                    documentation = cmp.config.window.bordered(),
+                  },
+                  mapping = {
+                    ['<c-space>'] = cmp.mapping.confirm({ select = true }),
+                    ['<c-p>']     = cmp.mapping.select_prev_item(select_opts),
+                    ['<c-n>']     = cmp.mapping.select_next_item(select_opts),
+                    ['<c-d>']     = cmp.mapping.scroll_docs(4),
+                    ['<c-u>']     = cmp.mapping.scroll_docs(-4),
+                    ['<c-e>']     = cmp.mapping.abort(),
+                  },
+                  sources = cmp.config.sources {
+                    { name = 'buffer' },
+                    { name = 'calc' },
+                    { name = 'crates' },
+                    { name = 'git' },
+                    { name = 'latex_symbols' },
+                    { name = 'nvim_lsp' },
+                    { name = 'path' },
+                    { name = 'treesitter' },
+                    { name = 'vsnip' },
+                  },
+                }
+              EOF
+            '';
+          }
+
           {
             plugin = nvim-lspconfig;
             config = let
-              configure = srv: "lua require 'lspconfig'.${srv}.setup {}";
+              configure = srv: ''
+                lspconfig.${srv}.setup {
+                  capabilities = caps,
+                }
+              '';
               servers = [
                 "clangd"
                 "rust_analyzer"
               ];
-            in
+              serverConfigs = lib.strings.concatStringsSep "\n" (builtins.map configure servers);
-              lib.strings.concatStringsSep "\n" (builtins.map configure servers);
+            in ''
+              lua <<EOF
+                local lspconfig = require 'lspconfig'
+                local caps = require 'cmp_nvim_lsp'.update_capabilities(
+                  vim.lsp.protocol.make_client_capabilities()
+                )
+                ${serverConfigs}
+              EOF
+            '';
           }
 
           {
@@ -161,6 +230,16 @@
             '';
           }
 
+          {
+            plugin = vim-vsnip;
+            config = ''
+              imap <expr> <c-k> vsnip#jumpable(1)  ? '<Plug>(vsnip-jump-next)' : '<Tab>'
+              smap <expr> <c-k> vsnip#jumpable(1)  ? '<Plug>(vsnip-jump-next)' : '<Tab>'
+              imap <expr> <c-j> vsnip#jumpable(-1) ? '<Plug>(vsnip-jump-prev)' : '<S-Tab>'
+              smap <expr> <c-j> vsnip#jumpable(-1) ? '<Plug>(vsnip-jump-prev)' : '<S-Tab>'
+            '';
+          }
+
           {
             plugin = vimwiki;
             # TODO: vimwiki config