[neovim] Give key bindings a little love; add GUI bindings for neovide

- Clean up the init interface. Move all the init methods into a single
  init_all() call.
- Add two keybindings for <M-j> and <M-k> to move by soft-wrapped lines in
  Normal mode
- Add a few key bindings for the usual shortcuts for cut/copy/paste when in GUI
  mode. In vim, D is the character that represents the Super/Apple key. So,
  <D-x>, <D-c>, and <D-v> now do what you'd expect.

config/nvim/init.lua

@@ -56,10 +56,7 @@ require 'treesitter'
 require 'lsp'
 
 local keys = require 'keys'
-keys.init_key_opts()
-keys.init_window_key_mappings()
-keys.init_diagnostic_key_mappings()
-keys.init_telescope_mappings()
+keys.init()
 
 local gui = require 'gui'
 gui.init()

config/nvim/lua/gui.lua

@@ -5,10 +5,13 @@ local function _init_neovide()
         return
     end
 
+    -- No use for these animations.
     vim.g.neovide_cursor_animation_length = 0
     vim.g.neovide_position_animation_length = 0
     vim.g.neovide_scroll_animation_length = 0
 
+    vim.g.neovide_input_macos_option_key_is_meta = "both"
+
     vim.cmd [[ colorscheme lunaperche ]]
 end
 

config/nvim/lua/keys.lua

@@ -2,10 +2,33 @@
 
 local map = vim.keymap.set
 
-local function init_key_opts()
+local function init_key_options()
     vim.g.mapleader = ","
 end
 
+local function navigation_mappings()
+    local options = { noremap = true }
+
+    -- Navigate by soft-wrapped lines using Alt/Option/Meta + jk
+    map({'n', 'v'}, '<M-k>', 'gk', options)
+    map({'n', 'v'}, '<M-j>', 'gj', options)
+end
+
+local function clipboard_mappings()
+    if not vim.fn.has('gui_running') then
+        return
+    end
+
+    local options = { noremap = true }
+
+    -- Copy to the system clipboard
+    map('v', '<D-c>', '"+y', options)
+    -- Cut to the system clipboard
+    map('v', '<D-x>', '"+x', options)
+    -- Paste from the system clipboard
+    map({'i', 'v'}, '<D-v>', '"+p', options)
+end
+
 local function window_key_mappings()
     local options = { silent = true }
 
@@ -70,10 +93,16 @@ local function telescope_mappings()
     map('n', '<leader>fh', builtin.help_tags, { desc = 'Telescope help tags' })
 end
 
+local function init_all_global_keybindings()
+    init_key_options()
+    clipboard_mappings()
+    window_key_mappings()
+    navigation_mappings()
+    diagnostic_mappings()
+    telescope_mappings()
+end
+
 return {
-    init_key_opts = init_key_opts,
-    init_window_key_mappings = window_key_mappings,
-    init_diagnostic_key_mappings = diagnostic_mappings,
+    init = init_all_global_keybindings,
     init_lsp_key_mappings = local_lsp_mappings,
-    init_telescope_mappings = telescope_mappings,
 }