[nvim] Add a new colors Lua module that deals with colors

it provides a single reloadColorscheme function that applies the colorscheme and
a few of my own customizations.

config/nvim/init.lua

@@ -1,16 +1,19 @@
 -- Eryn Wells <eryn@erynwells.me>
 
 vim.opt.runtimepath:prepend "~/.vim"
-vim.cmd [[ source ~/.vimrc.common ]]
+
+vim.cmd [[
+    source ~/.vimrc.common
+    source ~/.vim/plugins.vim 
+]]
 
 require 'configuration'
+require 'colors'
 require 'keys'
 require 'os'
 
-vim.cmd [[ source ~/.vim/plugins.vim ]]
-
-function ensure_metadata_directories_exist()
-    paths = {
+function ensureMetadataDirectoriesExist()
+    local paths = {
         vim.opt.backupdir:get(),
         vim.opt.directory:get(),
         vim.opt.undodir:get()
@@ -24,4 +27,4 @@ function ensure_metadata_directories_exist()
     end
 end
 
-ensure_metadata_directories_exist()
+ensureMetadataDirectoriesExist()

config/nvim/lua/colors.lua

@@ -0,0 +1,35 @@
+-- Eryn Wells <eryn@erynwells.me>
+
+-- Allow using GUI style colors (#RRGGBB hex codes) in color terminals. This is
+-- required for most modern color themes.
+vim.g.termguicolors = true
+
+function reloadColorscheme(colorschemeName)
+    vim.cmd {
+        cmd = "colorscheme",
+        args = {colorschemeName},
+    }
+
+    if vim.env.TERM_PROGRAM == "Apple_Terminal" then
+        -- Add a correction for Apple's Terminal.app, which doesn't support
+        -- 24-bit colors and needs some adjustment to cope.
+        vim.cmd [[
+            highlight default Folded cterm=bold term=bold ctermfg=NONE ctermbg=NONE
+            highlight default CursorLine term=underline cterm=NONE ctermbg=0
+            highlight default CursorLineNr term=underline cterm=NONE ctermfg=7 ctermbg=0
+        ]]
+    end
+
+    if vim.g.colors_name == "witchhazel" then
+        vim.cmd [[
+            highlight! default link LineNr CursorLineNr
+            highlight! default link CursorLineNr CursorLine
+        ]]
+    elseif vim.g.colors_name == "dracula" then
+        vim.cmd [[
+            highlight CursorLineNr guibg=#44475a
+        ]]
+    end
+end
+
+reloadColorscheme("dracula")