Add lsp/buffer nvim-cmp completion.

jrpotter/neovim/default.nix

@@ -9,6 +9,13 @@ let
     };
   };
 
+  nvim-cmp = {
+    plugin = pkgs.vimPlugins.nvim-cmp;
+    config = ''
+      require('init.cmp').setup()
+    '';
+  };
+
   nvim-dap = {
     plugin = pluginGit
       "e154fdb6d70b3765d71f296e718b29d8b7026a63"
@@ -30,19 +37,7 @@ let
       ]
     ));
     config = ''
-      require('nvim-treesitter.configs').setup {
-        auto_install = false,
-        highlight = { enable = true },
-        incremental_selection = {
-          enable = true,
-          keymaps = {
-            init_selection = '<Tab>',
-            node_incremental = '<Tab>',
-            node_decremental = '<S-Tab>',
-            scope_incremental = false,
-          },
-        },
-      }
+      require('init.treesitter').setup()
     '';
   };
 in
@@ -83,9 +78,12 @@ in
           inherit (p) plugin;
           config = "lua << EOF\n${p.config}\nEOF";
         } else p) [
+        nvim-cmp
         nvim-dap
         nvim-lspconfig
         nvim-treesitter
+        pkgs.vimPlugins.cmp-buffer
+        pkgs.vimPlugins.cmp-nvim-lsp
       ];
       viAlias = true;
       vimAlias = true;

jrpotter/neovim/lua/init/cmp.lua

@@ -0,0 +1,55 @@
+local M = {}
+
+local cmp = require('cmp')
+local cmp_buffer = require('cmp_buffer')
+
+function M.setup()
+  cmp.setup {
+    sources = {
+      {
+        name = 'nvim_lsp',
+      },
+      {
+        name = 'buffer',
+        option = {
+          -- Complete only on visible buffers.
+          get_bufnrs = function()
+            local bufs = {}
+            for _, win in ipairs(vim.api.nvim_list_wins()) do
+              bufs[vim.api.nvim_win_get_buf(win)] = true
+            end
+            return vim.tbl_keys(bufs)
+          end
+        },
+      },
+    },
+    sorting = {
+      comparators = {
+        function (...)
+          -- This also sorts completion results coming from other sources (e.g.
+          -- LSPs).
+          return cmp_buffer:compare_locality(...)
+        end,
+      },
+    },
+    mapping = {
+      ['<c-n>'] = cmp.mapping(function(fallback)
+        if cmp.visible() then cmp.select_next_item() else fallback() end
+      end, { 'i', 's' }),
+
+      ['<c-p>'] = cmp.mapping(function(fallback)
+        if cmp.visible() then cmp.select_prev_item() else fallback() end
+      end, { 'i', 's' }),
+
+      ['<c-l>'] = cmp.mapping(function(fallback)
+        if cmp.visible() then cmp.abort() else fallback() end
+      end, { 'i', 's' }),
+
+      ['<tab>'] = cmp.mapping(function(fallback)
+        if cmp.visible() then cmp.confirm() else fallback() end
+      end, { 'i', 's' }),
+    },
+  }
+end
+
+return M

jrpotter/neovim/lua/init/treesitter.lua

@@ -0,0 +1,12 @@
+local M = {}
+
+local configs = require('nvim-treesitter.configs')
+
+function M.setup()
+  configs.setup {
+    auto_install = false,
+    highlight = { enable = true },
+  }
+end
+
+return M