Resolve #99 (#103)

* initial work on #99

* remove comments

* goodbye neovim 0.6. Using new hl system, now working

7 files changed, 102 insertions, 172 deletions

diff --git a/lua/gruvbox/base.lua b/lua/gruvbox/base.lua
index 7092fb1..8016a7b 100644
--- a/lua/gruvbox/base.lua
+++ b/lua/gruvbox/base.lua
@@ -1,7 +1,12 @@
 local colors = require("gruvbox.colors")
-local styles = require("gruvbox.settings").styles
 local utils = require("gruvbox.utils")
 
+-- reset colors
+vim.cmd("hi clear")
+if vim.fn.exists("syntax_on") then
+  vim.cmd("syntax reset")
+end
+
 -- options (dark mode by default)
 local bg0 = colors.dark0
 local bg1 = colors.dark1
@@ -24,7 +29,7 @@ local aqua = colors.bright_aqua
 local orange = colors.bright_orange
 local gray = colors.gray
 
-local bg = vim.o.background
+local bg = vim.opt.background:get()
 if bg == nil then
   bg = "dark"
   vim.o.background = bg
@@ -89,17 +94,14 @@ local cursor_line = utils.get_color_from_var(vim.g.gruvbox_cursor_line, bg1, col
 
 local improved_strings_fg = fg1
 local improved_strings_bg = bg1
-local improved_strings_gui = styles.italic_strings
 
 local special_string_fg = orange
 local special_string_bg = bg1
-local special_string_gui = styles.italic_strings
 
-if not utils.tobool(vim.g.gruvbox_improved_strings) then
+if not vim.g.gruvbox_improved_strings then
   improved_strings_fg = green
   improved_strings_bg = nil
   special_string_bg = nil
-  special_string_gui = nil
 end
 
 -- neovim terminal mode colors
@@ -122,8 +124,6 @@ vim.g.terminal_color_15 = fg1
 
 vim.g.colors_name = "gruvbox"
 
-local table_concat = table.concat
-
 local base_group = {
   -- Base groups
   GruvboxFg0 = { fg = fg0 },
@@ -139,39 +139,39 @@ local base_group = {
   GruvboxBg4 = { fg = bg4 },
 
   GruvboxRed = { fg = red },
-  GruvboxRedBold = { fg = red, gui = styles.bold },
+  GruvboxRedBold = { fg = red, bold = vim.g.gruvbox_bold },
   GruvboxGreen = { fg = green },
-  GruvboxGreenBold = { fg = green, gui = styles.bold },
+  GruvboxGreenBold = { fg = green, bold = vim.g.gruvbox_bold },
   GruvboxYellow = { fg = yellow },
-  GruvboxYellowBold = { fg = yellow, gui = styles.bold },
+  GruvboxYellowBold = { fg = yellow, bold = vim.g.gruvbox_bold },
   GruvboxBlue = { fg = blue },
-  GruvboxBlueBold = { fg = blue, gui = styles.bold },
+  GruvboxBlueBold = { fg = blue, bold = vim.g.gruvbox_bold },
   GruvboxPurple = { fg = purple },
-  GruvboxPurpleBold = { fg = purple, gui = styles.bold },
+  GruvboxPurpleBold = { fg = purple, bold = vim.g.gruvbox_bold },
   GruvboxAqua = { fg = aqua },
-  GruvboxAquaBold = { fg = aqua, gui = styles.bold },
+  GruvboxAquaBold = { fg = aqua, bold = vim.g.gruvbox_bold },
   GruvboxOrange = { fg = orange },
-  GruvboxOrangeBold = { fg = orange, gui = styles.bold },
+  GruvboxOrangeBold = { fg = orange, bold = vim.g.gruvbox_bold },
 
-  GruvboxRedSign = { fg = red, bg = sign_column, gui = styles.invert_signs },
-  GruvboxGreenSign = { fg = green, bg = sign_column, gui = styles.invert_signs },
-  GruvboxYellowSign = { fg = yellow, bg = sign_column, gui = styles.invert_signs },
-  GruvboxBlueSign = { fg = blue, bg = sign_column, gui = styles.invert_signs },
-  GruvboxPurpleSign = { fg = purple, bg = sign_column, gui = styles.invert_signs },
-  GruvboxAquaSign = { fg = aqua, bg = sign_column, gui = styles.invert_signs },
-  GruvboxOrangeSign = { fg = orange, bg = sign_column, gui = styles.invert_signs },
+  GruvboxRedSign = { fg = red, bg = sign_column, inverse = vim.g.gruvbox_invert_signs },
+  GruvboxGreenSign = { fg = green, bg = sign_column, inverse = vim.g.gruvbox_invert_signs },
+  GruvboxYellowSign = { fg = yellow, bg = sign_column, inverse = vim.g.gruvbox_invert_signs },
+  GruvboxBlueSign = { fg = blue, bg = sign_column, inverse = vim.g.gruvbox_invert_signs },
+  GruvboxPurpleSign = { fg = purple, bg = sign_column, inverse = vim.g.gruvbox_invert_signs },
+  GruvboxAquaSign = { fg = aqua, bg = sign_column, inverse = vim.g.gruvbox_invert_signs },
+  GruvboxOrangeSign = { fg = orange, bg = sign_column, inverse = vim.g.gruvbox_invert_signs },
 
-  GruvboxRedUnderline = { gui = styles.undercurl, sp = red },
-  GruvboxGreenUnderline = { gui = styles.undercurl, sp = green },
-  GruvboxYellowUnderline = { gui = styles.undercurl, sp = yellow },
-  GruvboxBlueUnderline = { gui = styles.undercurl, sp = blue },
-  GruvboxPurpleUnderline = { gui = styles.undercurl, sp = purple },
-  GruvboxAquaUnderline = { gui = styles.undercurl, sp = aqua },
-  GruvboxOrangeUnderline = { gui = styles.undercurl, sp = orange },
+  GruvboxRedUnderline = { undercurl = vim.g.gruvbox_undercurl, sp = red },
+  GruvboxGreenUnderline = { undercurl = vim.g.gruvbox_undercurl, sp = green },
+  GruvboxYellowUnderline = { undercurl = vim.g.gruvbox_undercurl, sp = yellow },
+  GruvboxBlueUnderline = { undercurl = vim.g.gruvbox_undercurl, sp = blue },
+  GruvboxPurpleUnderline = { undercurl = vim.g.gruvbox_undercurl, sp = purple },
+  GruvboxAquaUnderline = { undercurl = vim.g.gruvbox_undercurl, sp = aqua },
+  GruvboxOrangeUnderline = { undercurl = vim.g.gruvbox_undercurl, sp = orange },
 
   ColorColumn = { bg = color_column },
   Conceal = { fg = blue },
-  Cursor = { gui = styles.inverse },
+  Cursor = { inverse = vim.g.gruvbox_inverse },
   lCursor = "Cursor",
   iCursor = "Cursor",
   vCursor = "Cursor",
@@ -179,54 +179,55 @@ local base_group = {
   CursorLine = { bg = cursor_line },
   CursorColumn = "CursorLine",
   Directory = "GruvboxGreenBold",
-  DiffAdd = { fg = green, bg = bg0, gui = styles.inverse },
-  DiffChange = { fg = aqua, bg = bg0, gui = styles.inverse },
-  DiffDelete = { fg = red, bg = bg0, gui = styles.inverse },
-  DiffText = { fg = yellow, bg = bg0, gui = styles.inverse },
-  ErrorMsg = { fg = bg0, bg = red, gui = styles.bold },
+  DiffAdd = { fg = green, bg = bg0, inverse = vim.g.gruvbox_inverse },
+  DiffChange = { fg = aqua, bg = bg0, inverse = vim.g.gruvbox_inverse },
+  DiffDelete = { fg = red, bg = bg0, inverse = vim.g.gruvbox_inverse },
+  DiffText = { fg = yellow, bg = bg0, inverse = vim.g.gruvbox_inverse },
+  ErrorMsg = { fg = bg0, bg = red, bold = vim.g.gruvbox_bold },
   VertSplit = { fg = bg3, bg = vert_split },
-  Folded = { fg = gray, bg = bg1, gui = styles.italic },
+  Folded = { fg = gray, bg = bg1, italic = vim.g.gruvbox_italic },
   FoldColumn = { fg = gray, bg = bg1 },
   SignColumn = { bg = sign_column },
-  IncSearch = { fg = hls_cursor, bg = bg0, gui = styles.inverse },
+  IncSearch = { fg = hls_cursor, bg = bg0, inverse = vim.g.gruvbox_inverse },
   LineNr = { fg = bg4, bg = number_column },
   CursorLineNr = { fg = yellow, bg = bg1 },
-  MatchParen = { bg = bg3, gui = styles.bold },
+  MatchParen = { bg = bg3, bold = vim.g.gruvbox_bold },
   ModeMsg = "GruvboxYellowBold",
   MoreMsg = "GruvboxYellowBold",
   NonText = "GruvboxBg2",
   Normal = { fg = fg1, bg = bg0 },
   Pmenu = { fg = fg1, bg = bg2 },
-  PmenuSel = { fg = bg2, bg = blue, gui = styles.bold },
+  PmenuSel = { fg = bg2, bg = blue, bold = vim.g.gruvbox_bold },
   PmenuSbar = { bg = bg2 },
   PmenuThumb = { bg = bg4 },
   Question = "GruvboxOrangeBold",
-  QuickFixLine = { bg = bg0, gui = styles.bold },
-  Search = { fg = hls_highlight, bg = bg0, gui = styles.inverse },
+  QuickFixLine = { bg = bg0, bold = vim.g.gruvbox_bold },
+  Search = { fg = hls_highlight, bg = bg0, inverse = vim.g.gruvbox_inverse },
   SpecialKey = "GruvboxFg4",
   SpellRare = "GruvboxPurpleUnderline",
   SpellBad = "GruvboxRedUnderline",
   SpellLocal = "GruvboxAquaUnderline",
-  SpellCap = utils.tobool(vim.g.gruvbox_improved_warnings) and {
+  SpellCap = vim.g.gruvbox_improved_warnings and {
     fg = green,
-    gui = table_concat({ styles.bold, styles.italic }, ","),
+    bold = vim.g.gruvbox_bold,
+    italic = vim.g.gruvbox_italic,
   } or "GruvboxBlueUnderline",
-  StatusLine = { fg = bg2, bg = fg1, gui = styles.inverse },
-  StatusLineNC = { fg = bg1, bg = fg4, gui = styles.inverse },
-  TabLineFill = { fg = bg4, bg = bg1, gui = styles.invert_tabline },
+  StatusLine = { fg = bg2, bg = fg1, inverse = vim.g.gruvbox_inverse },
+  StatusLineNC = { fg = bg1, bg = fg4, inverse = vim.g.gruvbox_inverse },
+  TabLineFill = { fg = bg4, bg = bg1, inverse = vim.g.gruvbox_invert_tabline },
   TabLine = "TabLineFill",
-  TabLineSel = { fg = tabline_sel, bg = bg1, gui = styles.invert_tabline },
+  TabLineSel = { fg = tabline_sel, bg = bg1, inverse = vim.g.gruvbox_invert_tabline },
   Title = "GruvboxGreenBold",
-  Visual = { bg = bg3, gui = styles.invert_selection },
+  Visual = { bg = bg3, inverse = vim.g.gruvbox_invert_selection },
   VisualNOS = "Visual",
   WarningMsg = "GruvboxRedBold",
-  WildMenu = { fg = blue, bg = bg2, gui = styles.bold },
+  WildMenu = { fg = blue, bg = bg2, bold = vim.g.gruvbox_bold },
   Constant = "GruvboxPurple",
-  Special = { fg = special_string_fg, bg = special_string_bg, gui = special_string_gui },
+  Special = { fg = special_string_fg, bg = special_string_bg, italic = vim.g.gruvbox_improved_strings },
   String = {
     fg = improved_strings_fg,
     bg = improved_strings_bg,
-    gui = improved_strings_gui,
+    italic = vim.g.gruvbox_italicize_strings,
   },
   Character = "GruvboxPurple",
   Number = "GruvboxPurple",
@@ -253,14 +254,14 @@ local base_group = {
   SpecialChar = "GruvboxRed",
   Tag = "GruvboxAquaBold",
   Delimiter = "GruvboxFg3",
-  Comment = { fg = gray, gui = styles.italic_comments },
+  Comment = { fg = gray, italic = vim.g.gruvbox_italic_comments },
   Debug = "GruvboxRed",
-  Underlined = { fg = blue, gui = styles.underline },
-  Bold = { gui = styles.bold },
-  Italic = { gui = styles.italic },
+  Underlined = { fg = blue, underline = vim.g.gruvbox_underline },
+  Bold = { bold = vim.g.gruvbox_bold },
+  Italic = { italic = vim.g.gruvbox_italic },
   Ignore = {},
-  Error = { fg = red, gui = table_concat({ styles.bold, styles.inverse }, ",") },
-  Todo = { fg = fg0, gui = table_concat({ styles.bold, styles.italic }, ",") },
+  Error = { fg = red, bold = vim.g.gruvbox_bold, inverse = vim.g.gruvbox_inverse },
+  Todo = { fg = fg0, bold = vim.g.gruvbox_bold, italic = vim.g.gruvbox_italic },
   diffAdded = "GruvboxGreen",
   diffRemoved = "GruvboxRed",
   diffChanged = "GruvboxAqua",
diff --git a/lua/gruvbox/init.lua b/lua/gruvbox/init.lua
index eb9ff71..cb55b9c 100644
--- a/lua/gruvbox/init.lua
+++ b/lua/gruvbox/init.lua
@@ -1,5 +1,5 @@
 local base = require("gruvbox.base")
-local plugins = require("gruvbox.plugins.highlights")
+local plugins = require("gruvbox.plugins")
 local languages = require("gruvbox.languages")
 local utils = require("gruvbox.utils")
 
@@ -8,7 +8,13 @@ local spec = utils.merge(specs)
 
 local M = {}
 M.load = function()
-  utils.highlights(spec)
+  if vim.version().minor < 7 then
+    vim.api.nvim_err_writeln("gruvbox.nvim: you must use neovim 0.7 or higher")
+    return
+  end
+
+  vim.opt.termguicolors = true
+  utils.add_highlights(spec)
 end
 
 return M
diff --git a/lua/gruvbox/languages.lua b/lua/gruvbox/languages.lua
index 394f52d..97cad80 100644
--- a/lua/gruvbox/languages.lua
+++ b/lua/gruvbox/languages.lua
@@ -1,6 +1,5 @@
 -- language specific higlights
 local base = require("gruvbox.base")
-local styles = require("gruvbox.settings").styles
 local utils = require("gruvbox.utils")
 local colors = require("gruvbox.colors")
 
@@ -69,11 +68,12 @@ local elixir = {
 }
 
 local markdown = {
-  markdownItalic = { fg = base.GruvboxFg3.fg, gui = styles.italic },
-  markdownBold = { fg = base.GruvboxFg3.fg, gui = styles.bold },
+  markdownItalic = { fg = base.GruvboxFg3.fg, bold = vim.g.gruvbox_italic },
+  markdownBold = { fg = base.GruvboxFg3.fg, bold = vim.g.gruvbox_bold },
   markdownBoldItalic = {
     fg = base.GruvboxFg3.fg,
-    gui = table.concat({ styles.bold, styles.italic }, ","),
+    bold = vim.g.gruvbox_bold,
+    italic = vim.g.gruvbox_italic,
   },
   markdownH1 = base.GruvboxGreenBold,
   markdownH2 = "markdownH1",
@@ -95,7 +95,7 @@ local markdown = {
   markdownHeadingDelimiter = base.GruvboxOrange,
   markdownUrl = base.GruvboxPurple,
   markdownUrlTitleDelimiter = base.GruvboxGreen,
-  markdownLinkText = { fg = base.GruvboxGray.fg, gui = styles.underline },
+  markdownLinkText = { fg = base.GruvboxGray.fg, underline = vim.g.gruvbox_underline },
   markdownIdDeclaration = "markdownLinkText",
 }
 
@@ -143,27 +143,31 @@ local html = {
   htmlArg = base.GruvboxOrange,
   htmlTagN = base.GruvboxFg1,
   htmlSpecialTagName = base.GruvboxBlue,
-  htmlLink = { fg = colors.fg4, gui = styles.underline },
+  htmlLink = { fg = colors.fg4, underline = vim.g.gruvbox_underline },
   htmlSpecialChar = "GruvboxRed",
-  htmlBold = { fg = colors.fg0, bg = colors.bg0, gui = styles.bold },
+  htmlBold = { fg = colors.fg0, bg = colors.bg0, bold = vim.g.gruvbox_bold },
   htmlBoldUnderline = {
     fg = colors.fg0,
     bg = colors.bg0,
-    gui = table.concat({ styles.bold, styles.underline }, ","),
+    bold = vim.g.gruvbox_bold,
+    underline = vim.g.gruvbox_underline,
   },
-  htmlBoldItalic = { fg = colors.fg0, bg = colors.bg0, gui = table.concat({ styles.bold, styles.italic }, ",") },
+  htmlBoldItalic = { fg = colors.fg0, bg = colors.bg0, bold = vim.g.gruvbox_bold, italic = vim.g.gruvbox_italic },
   htmlBoldUnderlineItalic = {
     fg = colors.fg0,
     bg = colors.bg0,
-    gui = table.concat({ styles.bold, styles.underline, styles.italic }, ","),
+    bold = vim.g.gruvbox_bold,
+    italic = vim.g.gruvbox_italic,
+    underline = vim.g.gruvbox_underline,
   },
-  htmlUnderline = { fg = colors.fg0, bg = colors.bg0, gui = styles.underline },
+  htmlUnderline = { fg = colors.fg0, bg = colors.bg0, underline = vim.g.gruvbox_underline },
   htmlUnderlineItalic = {
     fg = colors.fg0,
     bg = colors.bg0,
-    gui = table.concat({ styles.underline, styles.italic }, ","),
+    italic = vim.g.gruvbox_italic,
+    underline = vim.g.gruvbox_underline,
   },
-  htmlItalic = { fg = colors.fg0, bg = colors.bg0, gui = styles.italic },
+  htmlItalic = { fg = colors.fg0, bg = colors.bg0, bold = vim.g.gruvbox_italic },
 }
 
 local langs = utils.merge({
diff --git a/lua/gruvbox/plugins/lightline.lua b/lua/gruvbox/lightline.lua
index 3e3991e..3e3991e 100644
--- a/lua/gruvbox/plugins/lightline.lua
+++ b/lua/gruvbox/lightline.lua
diff --git a/lua/gruvbox/plugins/highlights.lua b/lua/gruvbox/plugins.lua
index f90c1be..cd95cb8 100644
--- a/lua/gruvbox/plugins/highlights.lua
+++ b/lua/gruvbox/plugins.lua
@@ -1,6 +1,5 @@
 -- 3rd party plugins highlights
 local base = require("gruvbox.base")
-local styles = require("gruvbox.settings").styles
 local colors = require("gruvbox.colors")
 
 local plugins = {
@@ -60,9 +59,9 @@ local plugins = {
   TSInclude = base.Include,
   TSVariableBuiltin = base.Special,
   TSText = "TSNone",
-  TSStrong = { gui = styles.bold },
-  TSEmphasis = { gui = styles.italic_strings },
-  TSUnderline = { gui = styles.underline },
+  TSStrong = { bold = vim.g.gruvbox_bold },
+  TSEmphasis = { italic = vim.g.gruvbox_italicize_strings },
+  TSUnderline = { underline = vim.g.gruvbox_underline },
   TSComment = base.Comment,
   TSStructure = base.GruvboxOrange,
   TSTag = base.GruvboxOrange,
@@ -106,13 +105,13 @@ local plugins = {
   LspSagaCodeActionTruncateLine = base.NormalNC,
   LspSagaCodeActionContent = base.Normal,
   LspSagaRenamePromptPrefix = base.GruvboxFg2,
-  LspSagaRenameBorder = { gui = styles.bold },
-  LspSagaHoverBorder = { gui = styles.bold },
-  LspSagaSignatureHelpBorder = { gui = styles.bold },
-  LspSagaCodeActionBorder = { gui = styles.bold },
+  LspSagaRenameBorder = { bold = vim.g.gruvbox_bold },
+  LspSagaHoverBorder = { bold = vim.g.gruvbox_bold },
+  LspSagaSignatureHelpBorder = { bold = vim.g.gruvbox_bold },
+  LspSagaCodeActionBorder = { bold = vim.g.gruvbox_bold },
   LspSagaAutoPreview = {},
-  LspSagaDefPreviewBorder = { gui = styles.bold },
-  LspLinesDiagBorder = { gui = styles.bold },
+  LspSagaDefPreviewBorder = { bold = vim.g.gruvbox_bold },
+  LspLinesDiagBorder = { bold = vim.g.gruvbox_bold },
   -- vim-startify
   StartifyBracket = base.GruvboxFg3,
   StartifyFile = base.GruvboxFg1,
@@ -220,7 +219,7 @@ local plugins = {
   CmpItemAbbr = base.GruvboxFg0,
   CmpItemAbbrDeprecated = base.GruvboxFg0,
   CmpItemAbbrMatch = base.GruvboxBlue,
-  CmpItemAbbrMatchFuzzy = { gui = styles.underline, fg = base.GruvboxAqua.fg },
+  CmpItemAbbrMatchFuzzy = { underline = vim.g.gruvbox_underline, fg = base.GruvboxAqua.fg },
   CmpItemKind = base.GruvboxOrange,
   CmpItemKindClass = base.GruvboxGreen,
   CmpItemKindConstructor = base.GruvboxGreen,
@@ -238,9 +237,9 @@ local plugins = {
   CmpItemMenu = base.GruvboxGray,
   -- LSP
   LspCodeLens = base.GruvboxGray,
-  LspReferenceRead = { bg = base.GruvboxBg2.fg, gui = styles.underline },
-  LspReferenceText = { bg = base.GruvboxBg2.fg, gui = styles.underline },
-  LspReferenceWrite = { bg = base.GruvboxBg2.fg, gui = styles.underline },
+  LspReferenceRead = { bg = base.GruvboxBg2.fg, underline = vim.g.gruvbox_underline },
+  LspReferenceText = { bg = base.GruvboxBg2.fg, underline = vim.g.gruvbox_underline },
+  LspReferenceWrite = { bg = base.GruvboxBg2.fg, underline = vim.g.gruvbox_underline },
   -- Diagnostic
   DiagnosticError = base.GruvboxRed,
   DiagnosticSignError = base.GruvboxRedSign,
diff --git a/lua/gruvbox/settings.lua b/lua/gruvbox/settings.lua
index 3cd1078..c72b8c6 100644
--- a/lua/gruvbox/settings.lua
+++ b/lua/gruvbox/settings.lua
@@ -1,6 +1,4 @@
 -- gruvbox settings handler
-local utils = require("gruvbox.utils")
-
 local settings = {
   contrast_dark = "medium",
   contrast_light = "medium",
@@ -19,19 +17,6 @@ local settings = {
   invert_intend_guides = false,
 }
 
-local styles = {
-  italic = "italic",
-  bold = "bold",
-  underline = "underline",
-  inverse = "inverse",
-  undercurl = "undercurl",
-  invert_signs = "",
-  invert_selection = "inverse",
-  invert_tabline = "",
-  italic_comments = "italic",
-  italic_strings = "NONE",
-}
-
 -- setting default values
 for k, val in pairs(settings) do
   local key = "gruvbox_" .. k
@@ -40,45 +25,4 @@ for k, val in pairs(settings) do
   end
 end
 
--- styles check
-if not utils.tobool(vim.g.gruvbox_bold) then
-  styles.bold = "NONE"
-end
-
-if not utils.tobool(vim.g.gruvbox_underline) then
-  styles.underline = "NONE"
-end
-
-if not utils.tobool(vim.g.gruvbox_italic) then
-  styles.italic = "NONE"
-end
-
-if not utils.tobool(vim.g.gruvbox_inverse) then
-  styles.inverse = "NONE"
-end
-
-if not utils.tobool(vim.g.gruvbox_undercurl) then
-  styles.undercurl = "NONE"
-end
-
-if utils.tobool(vim.g.gruvbox_invert_signs) then
-  styles.invert_signs = "inverse"
-end
-
-if not utils.tobool(vim.g.gruvbox_invert_selection) then
-  styles.invert_selection = "NONE"
-end
-
-if utils.tobool(vim.g.gruvbox_invert_tabline) then
-  styles.invert_tabline = "inverse"
-end
-
-if not utils.tobool(vim.g.gruvbox_italicize_comments) then
-  styles.italic_comments = "NONE"
-end
-
-if utils.tobool(vim.g.gruvbox_italicize_strings) then
-  styles.italic_strings = "italic"
-end
-
-return { settings = settings, styles = styles }
+return settings
diff --git a/lua/gruvbox/utils.lua b/lua/gruvbox/utils.lua
index f9b5ccf..8138899 100644
--- a/lua/gruvbox/utils.lua
+++ b/lua/gruvbox/utils.lua
@@ -1,12 +1,7 @@
 -- util functions
 local M = {}
-
-M.tobool = function(val)
-  if val == 0 or not val then
-    return false
-  end
-  return true
-end
+local hl = vim.api.nvim_set_hl
+local link = vim.highlight.link
 
 -- check if vim.g.gruvbox_* color exists in current palette, return default color
 -- otherwise
@@ -34,31 +29,12 @@ M.merge = function(tbls)
   return source
 end
 
-M.highlights = function(hls)
+M.add_highlights = function(hls)
   for k, v in pairs(hls) do
     if type(v) == "table" then
-      -- no blank strings allowed for guifg, guibg, guisp and gui
-      local opt = {}
-      for kk, vv in pairs(v) do
-        if vv == "" then
-          vv = nil
-        end
-
-        opt[kk] = vv
-      end
-
-      vim.cmd(
-        string.format(
-          "hi %s guifg=%s guibg=%s guisp=%s gui=%s",
-          k,
-          opt.fg or "NONE",
-          opt.bg or "NONE",
-          opt.sp or "NONE",
-          opt.gui or "NONE"
-        )
-      )
+      hl(0, k, v)
     else
-      vim.cmd(string.format("hi! link %s %s", k, v))
+      link(k, v, true)
     end
   end
 end