Merge pull request #2 from br1anchen/master

Add support for 0xAARRGGBB and vritualtext mode fix

3 files changed, 626 insertions, 479 deletions

diff --git a/.stylua.toml b/.stylua.toml
new file mode 100644
index 0000000..e9bf648
--- /dev/null
+++ b/.stylua.toml
@@ -0,0 +1,6 @@
+column_width = 120
+line_endings = "Unix"
+indent_type = "Spaces"
+indent_width = 3
+quote_style = "AutoPreferDouble"
+no_call_parentheses = true
diff --git a/README.md b/README.md
index 1ec45f5..6fda6a2 100644
--- a/README.md
+++ b/README.md
@@ -41,7 +41,7 @@ written with performance in mind and leveraging the excellent LuaJIT and a
 handwritten parser, updates can be done in real time. There are plugins such as
 [hexokinase](https://github.com/RRethy/vim-hexokinase) which have good
 performance, but it has some difficulty with becoming out of sync. The downside
-is that *this only works for Neovim*, and that will never change.
+is that _this only works for Neovim_, and that will never change.
 
 Additionally, having a Lua API that's available means users can use this as a
 library to do custom highlighting themselves.
@@ -64,8 +64,10 @@ library to do custom highlighting themselves.
 ```
 
 MODES:
+
 - `foreground`: sets the foreground text color.
 - `background`: sets the background text color.
+- `virtualtext`: indicate the color behind the virtualtext.
 
 For basic setup, you can use a command like the following.
 
@@ -109,7 +111,6 @@ require 'colorizer'.setup {
 }
 ```
 
-
 For lower level interface, see the [LuaDocs for API details](https://norcalli.github.io/luadoc/nvim-colorizer.lua/modules/colorizer.html) or use `:h colorizer.lua` once installed.
 
 ## Commands
@@ -139,7 +140,6 @@ buffer.
 Toggle highlighting of the current buffer.
 ```
 
-
 ## Caveats
 
 If the file you are editing has no filetype, the plugin won't be attached, as
diff --git a/lua/colorizer.lua b/lua/colorizer.lua
index e726c6c..9183f9e 100644
--- a/lua/colorizer.lua
+++ b/lua/colorizer.lua
@@ -1,9 +1,9 @@
 --- Highlights terminal CSI ANSI color codes.
 -- @module colorizer
-local nvim = require 'colorizer/nvim'
-local Trie = require 'colorizer/trie'
-local bit = require 'bit'
-local ffi = require 'ffi'
+local nvim = require "colorizer/nvim"
+local Trie = require "colorizer/trie"
+local bit = require "bit"
+local ffi = require "ffi"
 
 local nvim_buf_add_highlight = vim.api.nvim_buf_add_highlight
 local nvim_buf_clear_namespace = vim.api.nvim_buf_clear_namespace
@@ -18,55 +18,56 @@ local COLOR_MAP
 local COLOR_TRIE
 local COLOR_NAME_MINLEN, COLOR_NAME_MAXLEN
 local COLOR_NAME_SETTINGS = {
-	lowercase = true;
-	strip_digits = false;
+   lowercase = true,
+   strip_digits = false,
 }
 
 --- Setup the COLOR_MAP and COLOR_TRIE
 local function initialize_trie()
-	if not COLOR_TRIE then
-		COLOR_MAP = {}
-		COLOR_TRIE = Trie()
-		for k, v in pairs(nvim.get_color_map()) do
-			if not (COLOR_NAME_SETTINGS.strip_digits and k:match("%d+$")) then
-				COLOR_NAME_MINLEN = COLOR_NAME_MINLEN and min(#k, COLOR_NAME_MINLEN) or #k
-				COLOR_NAME_MAXLEN = COLOR_NAME_MAXLEN and max(#k, COLOR_NAME_MAXLEN) or #k
-				local rgb_hex = tohex(v, 6)
-				COLOR_MAP[k] = rgb_hex
-				COLOR_TRIE:insert(k)
-				if COLOR_NAME_SETTINGS.lowercase then
-					local lowercase = k:lower()
-					COLOR_MAP[lowercase] = rgb_hex
-					COLOR_TRIE:insert(lowercase)
-				end
-			end
-		end
-	end
+   if not COLOR_TRIE then
+      COLOR_MAP = {}
+      COLOR_TRIE = Trie()
+      for k, v in pairs(nvim.get_color_map()) do
+         if not (COLOR_NAME_SETTINGS.strip_digits and k:match "%d+$") then
+            COLOR_NAME_MINLEN = COLOR_NAME_MINLEN and min(#k, COLOR_NAME_MINLEN) or #k
+            COLOR_NAME_MAXLEN = COLOR_NAME_MAXLEN and max(#k, COLOR_NAME_MAXLEN) or #k
+            local rgb_hex = tohex(v, 6)
+            COLOR_MAP[k] = rgb_hex
+            COLOR_TRIE:insert(k)
+            if COLOR_NAME_SETTINGS.lowercase then
+               local lowercase = k:lower()
+               COLOR_MAP[lowercase] = rgb_hex
+               COLOR_TRIE:insert(lowercase)
+            end
+         end
+      end
+   end
 end
 
 local function merge(...)
-	local res = {}
-	for i = 1,select("#", ...) do
-		local o = select(i, ...)
-		for k,v in pairs(o) do
-			res[k] = v
-		end
-	end
-	return res
+   local res = {}
+   for i = 1, select("#", ...) do
+      local o = select(i, ...)
+      for k, v in pairs(o) do
+         res[k] = v
+      end
+   end
+   return res
 end
 
 local DEFAULT_OPTIONS = {
-	RGB			 = true;				 -- #RGB hex codes
-	RRGGBB	 = true;				 -- #RRGGBB hex codes
-	names		 = true;				 -- "Name" codes like Blue or blue
-	RRGGBBAA = false;				 -- #RRGGBBAA hex codes
-	rgb_fn	 = false;				 -- CSS rgb() and rgba() functions
-	hsl_fn	 = false;				 -- CSS hsl() and hsla() functions
-	css			 = false;				 -- Enable all CSS features: rgb_fn, hsl_fn, names, RGB, RRGGBB
-	css_fn	 = false;				 -- Enable all CSS *functions*: rgb_fn, hsl_fn
-	-- Available modes: foreground, background, sign, virtualtext
-	mode		 = 'background'; -- Set the display mode.
-	virtualtext = '■';
+   RGB = true, -- #RGB hex codes
+   RRGGBB = true, -- #RRGGBB hex codes
+   names = true, -- "Name" codes like Blue or blue
+   RRGGBBAA = false, -- #RRGGBBAA hex codes
+   AARRGGBB = false, -- 0xAARRGGBB hex codes
+   rgb_fn = false, -- CSS rgb() and rgba() functions
+   hsl_fn = false, -- CSS hsl() and hsla() functions
+   css = false, -- Enable all CSS features: rgb_fn, hsl_fn, names, RGB, RRGGBB
+   css_fn = false, -- Enable all CSS *functions*: rgb_fn, hsl_fn
+   -- Available modes: foreground, background, sign, virtualtext
+   mode = "background", -- Set the display mode.
+   virtualtext = "■",
 }
 
 -- -- TODO use rgb as the return value from the matcher functions
@@ -80,150 +81,213 @@ local DEFAULT_OPTIONS = {
 
 -- Create a lookup table where the bottom 4 bits are used to indicate the
 -- category and the top 4 bits are the hex value of the ASCII byte.
-local BYTE_CATEGORY = ffi.new 'uint8_t[256]'
-local CATEGORY_DIGIT		= lshift(1, 0);
-local CATEGORY_ALPHA		= lshift(1, 1);
-local CATEGORY_HEX			= lshift(1, 2);
+local BYTE_CATEGORY = ffi.new "uint8_t[256]"
+local CATEGORY_DIGIT = lshift(1, 0)
+local CATEGORY_ALPHA = lshift(1, 1)
+local CATEGORY_HEX = lshift(1, 2)
 local CATEGORY_ALPHANUM = bor(CATEGORY_ALPHA, CATEGORY_DIGIT)
 do
-	local b = string.byte
-	for i = 0, 255 do
-		local v = 0
-		-- Digit is bit 1
-		if i >= b'0' and i <= b'9' then
-			v = bor(v, lshift(1, 0))
-			v = bor(v, lshift(1, 2))
-			v = bor(v, lshift(i - b'0', 4))
-		end
-		local lowercase = bor(i, 0x20)
-		-- Alpha is bit 2
-		if lowercase >= b'a' and lowercase <= b'z' then
-			v = bor(v, lshift(1, 1))
-			if lowercase <= b'f' then
-				v = bor(v, lshift(1, 2))
-				v = bor(v, lshift(lowercase - b'a'+10, 4))
-			end
-		end
-		BYTE_CATEGORY[i] = v
-	end
+   local b = string.byte
+   for i = 0, 255 do
+      local v = 0
+      -- Digit is bit 1
+      if i >= b "0" and i <= b "9" then
+         v = bor(v, lshift(1, 0))
+         v = bor(v, lshift(1, 2))
+         v = bor(v, lshift(i - b "0", 4))
+      end
+      local lowercase = bor(i, 0x20)
+      -- Alpha is bit 2
+      if lowercase >= b "a" and lowercase <= b "z" then
+         v = bor(v, lshift(1, 1))
+         if lowercase <= b "f" then
+            v = bor(v, lshift(1, 2))
+            v = bor(v, lshift(lowercase - b "a" + 10, 4))
+         end
+      end
+      BYTE_CATEGORY[i] = v
+   end
 end
 
 local function byte_is_hex(byte)
-	return band(BYTE_CATEGORY[byte], CATEGORY_HEX) ~= 0
+   return band(BYTE_CATEGORY[byte], CATEGORY_HEX) ~= 0
 end
 
 local function byte_is_alphanumeric(byte)
-	local category = BYTE_CATEGORY[byte]
-	return band(category, CATEGORY_ALPHANUM) ~= 0
+   local category = BYTE_CATEGORY[byte]
+   return band(category, CATEGORY_ALPHANUM) ~= 0
 end
 
 local function parse_hex(b)
-	return rshift(BYTE_CATEGORY[b], 4)
+   return rshift(BYTE_CATEGORY[b], 4)
 end
 
 local function percent_or_hex(v)
-	if v:sub(-1,-1) == "%" then
-		return tonumber(v:sub(1,-2))/100*255
-	end
-	local x = tonumber(v)
-	if x > 255 then return end
-	return x
+   if v:sub(-1, -1) == "%" then
+      return tonumber(v:sub(1, -2)) / 100 * 255
+   end
+   local x = tonumber(v)
+   if x > 255 then
+      return
+   end
+   return x
 end
 
 --- Determine whether to use black or white text
 -- Ref: https://stackoverflow.com/a/1855903/837964
 -- https://stackoverflow.com/questions/596216/formula-to-determine-brightness-of-rgb-color
 local function color_is_bright(r, g, b)
-	-- Counting the perceptive luminance - human eye favors green color
-	local luminance = (0.299*r + 0.587*g + 0.114*b)/255
-	if luminance > 0.5 then
-		return true -- Bright colors, black font
-	else
-		return false -- Dark colors, white font
-	end
+   -- Counting the perceptive luminance - human eye favors green color
+   local luminance = (0.299 * r + 0.587 * g + 0.114 * b) / 255
+   if luminance > 0.5 then
+      return true -- Bright colors, black font
+   else
+      return false -- Dark colors, white font
+   end
 end
 
 -- https://gist.github.com/mjackson/5311256
 local function hue_to_rgb(p, q, t)
-	if t < 0 then t = t + 1 end
-	if t > 1 then t = t - 1 end
-	if t < 1/6 then return p + (q - p) * 6 * t end
-	if t < 1/2 then return q end
-	if t < 2/3 then return p + (q - p) * (2/3 - t) * 6 end
-	return p
+   if t < 0 then
+      t = t + 1
+   end
+   if t > 1 then
+      t = t - 1
+   end
+   if t < 1 / 6 then
+      return p + (q - p) * 6 * t
+   end
+   if t < 1 / 2 then
+      return q
+   end
+   if t < 2 / 3 then
+      return p + (q - p) * (2 / 3 - t) * 6
+   end
+   return p
 end
 
 local function hsl_to_rgb(h, s, l)
-	if h > 1 or s > 1 or l > 1 then return end
-	if s == 0 then
-		local r = l * 255
-		return r, r, r
-	end
-	local q
-	if l < 0.5 then
-		q = l * (1 + s)
-	else
-		q = l + s - l * s
-	end
-	local p = 2 * l - q
-	return 255*hue_to_rgb(p, q, h + 1/3), 255*hue_to_rgb(p, q, h), 255*hue_to_rgb(p, q, h - 1/3)
+   if h > 1 or s > 1 or l > 1 then
+      return
+   end
+   if s == 0 then
+      local r = l * 255
+      return r, r, r
+   end
+   local q
+   if l < 0.5 then
+      q = l * (1 + s)
+   else
+      q = l + s - l * s
+   end
+   local p = 2 * l - q
+   return 255 * hue_to_rgb(p, q, h + 1 / 3), 255 * hue_to_rgb(p, q, h), 255 * hue_to_rgb(p, q, h - 1 / 3)
 end
 
 local function color_name_parser(line, i)
-	if i > 1 and byte_is_alphanumeric(line:byte(i-1)) then
-		return
-	end
-	if #line < i + COLOR_NAME_MINLEN - 1 then return end
-	local prefix = COLOR_TRIE:longest_prefix(line, i)
-	if prefix then
-		-- Check if there is a letter here so as to disallow matching here.
-		-- Take the Blue out of Blueberry
-		-- Line end or non-letter.
-		local next_byte_index = i + #prefix
-		if #line >= next_byte_index and byte_is_alphanumeric(line:byte(next_byte_index)) then
-			return
-		end
-		return #prefix, COLOR_MAP[prefix]
-	end
+   if i > 1 and byte_is_alphanumeric(line:byte(i - 1)) then
+      return
+   end
+   if #line < i + COLOR_NAME_MINLEN - 1 then
+      return
+   end
+   local prefix = COLOR_TRIE:longest_prefix(line, i)
+   if prefix then
+      -- Check if there is a letter here so as to disallow matching here.
+      -- Take the Blue out of Blueberry
+      -- Line end or non-letter.
+      local next_byte_index = i + #prefix
+      if #line >= next_byte_index and byte_is_alphanumeric(line:byte(next_byte_index)) then
+         return
+      end
+      return #prefix, COLOR_MAP[prefix]
+   end
 end
 
 local b_hash = ("#"):byte()
 local function rgb_hex_parser(line, i, minlen, maxlen)
-	if i > 1 and byte_is_alphanumeric(line:byte(i-1)) then
-		return
-	end
-	if line:byte(i) ~= b_hash then
-		return
-	end
-	local j = i + 1
-	if #line < j + minlen - 1 then return end
-	local n = j + maxlen
-	local alpha
-	local v = 0
-	while j <= min(n, #line) do
-		local b = line:byte(j)
-		if not byte_is_hex(b) then break end
-		if j - i >= 7 then
-			alpha = parse_hex(b) + lshift(alpha or 0, 4)
-		else
-			v = parse_hex(b) + lshift(v, 4)
-		end
-		j = j + 1
-	end
-	if #line >= j and byte_is_alphanumeric(line:byte(j)) then
-		return
-	end
-	local length = j - i
-	if length ~= 4 and length ~= 7 and length ~= 9 then return end
-	if alpha then
-		alpha = tonumber(alpha)/255
-		local r = floor(band(rshift(v, 16), 0xFF)*alpha)
-		local g = floor(band(rshift(v, 8), 0xFF)*alpha)
-		local b = floor(band(v, 0xFF)*alpha)
-		v = bor(lshift(r, 16), lshift(g, 8), b)
-		return 9, tohex(v, 6)
-	end
-	return length, line:sub(i+1, i+length-1)
+   if i > 1 and byte_is_alphanumeric(line:byte(i - 1)) then
+      return
+   end
+   if line:byte(i) ~= b_hash then
+      return
+   end
+   local j = i + 1
+   if #line < j + minlen - 1 then
+      return
+   end
+   local n = j + maxlen
+   local alpha
+   local v = 0
+   while j <= min(n, #line) do
+      local b = line:byte(j)
+      if not byte_is_hex(b) then
+         break
+      end
+      if j - i >= 7 then
+         alpha = parse_hex(b) + lshift(alpha or 0, 4)
+      else
+         v = parse_hex(b) + lshift(v, 4)
+      end
+      j = j + 1
+   end
+   if #line >= j and byte_is_alphanumeric(line:byte(j)) then
+      return
+   end
+   local length = j - i
+   if length ~= 4 and length ~= 7 and length ~= 9 then
+      return
+   end
+   if alpha then
+      alpha = tonumber(alpha) / 255
+      local r = floor(band(rshift(v, 16), 0xFF) * alpha)
+      local g = floor(band(rshift(v, 8), 0xFF) * alpha)
+      local b = floor(band(v, 0xFF) * alpha)
+      v = bor(lshift(r, 16), lshift(g, 8), b)
+      return 9, tohex(v, 6)
+   end
+   return length, line:sub(i + 1, i + length - 1)
+end
+
+local RGB_FUNCTION_TRIE = Trie { "0x" }
+local function rgb_0x_parser(line, i)
+   local prefix = RGB_FUNCTION_TRIE:longest_prefix(line:sub(i))
+   if not prefix then
+      return
+   end
+
+   local j = i + 2
+   if #line < 10 then
+      return
+   end
+   local n = j + 8
+   local alpha
+   local v = 0
+   while j <= min(n, #line) do
+      local b = line:byte(j)
+      if not byte_is_hex(b) then
+         break
+      end
+      if j - i <= 3 then
+         alpha = parse_hex(b) + lshift(alpha or 0, 4)
+      else
+         v = parse_hex(b) + lshift(v, 4)
+      end
+      j = j + 1
+   end
+   if #line >= j and byte_is_alphanumeric(line:byte(j)) then
+      return
+   end
+   local length = j - i
+   if length ~= 10 then
+      return
+   end
+   alpha = tonumber(alpha) / 255
+   local r = floor(band(rshift(v, 16), 0xFF) * alpha)
+   local g = floor(band(rshift(v, 8), 0xFF) * alpha)
+   local b = floor(band(v, 0xFF) * alpha)
+   v = bor(lshift(r, 16), lshift(g, 8), b)
+   return length, tohex(v, 6)
 end
 
 -- TODO consider removing the regexes here
@@ -231,94 +295,162 @@ end
 -- Things like pumblend might be useful here.
 local css_fn = {}
 do
-	local CSS_RGB_FN_MINIMUM_LENGTH = #'rgb(0,0,0)' - 1
-	local CSS_RGBA_FN_MINIMUM_LENGTH = #'rgba(0,0,0,0)' - 1
-	local CSS_HSL_FN_MINIMUM_LENGTH = #'hsl(0,0%,0%)' - 1
-	local CSS_HSLA_FN_MINIMUM_LENGTH = #'hsla(0,0%,0%,0)' - 1
-	function css_fn.rgb(line, i)
-		if #line < i + CSS_RGB_FN_MINIMUM_LENGTH then return end
-		local r, g, b, match_end = line:sub(i):match("^rgb%(%s*(%d+%%?)%s*,%s*(%d+%%?)%s*,%s*(%d+%%?)%s*%)()")
-		if not match_end then return end
-		r = percent_or_hex(r) if not r then return end
-		g = percent_or_hex(g) if not g then return end
-		b = percent_or_hex(b) if not b then return end
-		local rgb_hex = tohex(bor(lshift(r, 16), lshift(g, 8), b), 6)
-		return match_end - 1, rgb_hex
-	end
-	function css_fn.hsl(line, i)
-		if #line < i + CSS_HSL_FN_MINIMUM_LENGTH then return end
-		local h, s, l, match_end = line:sub(i):match("^hsl%(%s*(%d+)%s*,%s*(%d+)%%%s*,%s*(%d+)%%%s*%)()")
-		if not match_end then return end
-		h = tonumber(h) if h > 360 then return end
-		s = tonumber(s) if s > 100 then return end
-		l = tonumber(l) if l > 100 then return end
-		local r, g, b = hsl_to_rgb(h/360, s/100, l/100)
-		if r == nil or g == nil or b == nil then return end
-		local rgb_hex = tohex(bor(lshift(floor(r), 16), lshift(floor(g), 8), floor(b)), 6)
-		return match_end - 1, rgb_hex
-	end
-	function css_fn.rgba(line, i)
-		if #line < i + CSS_RGBA_FN_MINIMUM_LENGTH then return end
-		local r, g, b, a, match_end = line:sub(i):match("^rgba%(%s*(%d+%%?)%s*,%s*(%d+%%?)%s*,%s*(%d+%%?)%s*,%s*([.%d]+)%s*%)()")
-		if not match_end then return end
-		a = tonumber(a) if not a or a > 1 then return end
-		r = percent_or_hex(r) if not r then return end
-		g = percent_or_hex(g) if not g then return end
-		b = percent_or_hex(b) if not b then return end
-		local rgb_hex = tohex(bor(lshift(floor(r*a), 16), lshift(floor(g*a), 8), floor(b*a)), 6)
-		return match_end - 1, rgb_hex
-	end
-	function css_fn.hsla(line, i)
-		if #line < i + CSS_HSLA_FN_MINIMUM_LENGTH then return end
-		local h, s, l, a, match_end = line:sub(i):match("^hsla%(%s*(%d+)%s*,%s*(%d+)%%%s*,%s*(%d+)%%%s*,%s*([.%d]+)%s*%)()")
-		if not match_end then return end
-		a = tonumber(a) if not a or a > 1 then return end
-		h = tonumber(h) if h > 360 then return end
-		s = tonumber(s) if s > 100 then return end
-		l = tonumber(l) if l > 100 then return end
-		local r, g, b = hsl_to_rgb(h/360, s/100, l/100)
-		if r == nil or g == nil or b == nil then return end
-		local rgb_hex = tohex(bor(lshift(floor(r*a), 16), lshift(floor(g*a), 8), floor(b*a)), 6)
-		return match_end - 1, rgb_hex
-	end
+   local CSS_RGB_FN_MINIMUM_LENGTH = #"rgb(0,0,0)" - 1
+   local CSS_RGBA_FN_MINIMUM_LENGTH = #"rgba(0,0,0,0)" - 1
+   local CSS_HSL_FN_MINIMUM_LENGTH = #"hsl(0,0%,0%)" - 1
+   local CSS_HSLA_FN_MINIMUM_LENGTH = #"hsla(0,0%,0%,0)" - 1
+   function css_fn.rgb(line, i)
+      if #line < i + CSS_RGB_FN_MINIMUM_LENGTH then
+         return
+      end
+      local r, g, b, match_end = line:sub(i):match "^rgb%(%s*(%d+%%?)%s*,%s*(%d+%%?)%s*,%s*(%d+%%?)%s*%)()"
+      if not match_end then
+         return
+      end
+      r = percent_or_hex(r)
+      if not r then
+         return
+      end
+      g = percent_or_hex(g)
+      if not g then
+         return
+      end
+      b = percent_or_hex(b)
+      if not b then
+         return
+      end
+      local rgb_hex = tohex(bor(lshift(r, 16), lshift(g, 8), b), 6)
+      return match_end - 1, rgb_hex
+   end
+   function css_fn.hsl(line, i)
+      if #line < i + CSS_HSL_FN_MINIMUM_LENGTH then
+         return
+      end
+      local h, s, l, match_end = line:sub(i):match "^hsl%(%s*(%d+)%s*,%s*(%d+)%%%s*,%s*(%d+)%%%s*%)()"
+      if not match_end then
+         return
+      end
+      h = tonumber(h)
+      if h > 360 then
+         return
+      end
+      s = tonumber(s)
+      if s > 100 then
+         return
+      end
+      l = tonumber(l)
+      if l > 100 then
+         return
+      end
+      local r, g, b = hsl_to_rgb(h / 360, s / 100, l / 100)
+      if r == nil or g == nil or b == nil then
+         return
+      end
+      local rgb_hex = tohex(bor(lshift(floor(r), 16), lshift(floor(g), 8), floor(b)), 6)
+      return match_end - 1, rgb_hex
+   end
+   function css_fn.rgba(line, i)
+      if #line < i + CSS_RGBA_FN_MINIMUM_LENGTH then
+         return
+      end
+      local r, g, b, a, match_end = line
+         :sub(i)
+         :match "^rgba%(%s*(%d+%%?)%s*,%s*(%d+%%?)%s*,%s*(%d+%%?)%s*,%s*([.%d]+)%s*%)()"
+      if not match_end then
+         return
+      end
+      a = tonumber(a)
+      if not a or a > 1 then
+         return
+      end
+      r = percent_or_hex(r)
+      if not r then
+         return
+      end
+      g = percent_or_hex(g)
+      if not g then
+         return
+      end
+      b = percent_or_hex(b)
+      if not b then
+         return
+      end
+      local rgb_hex = tohex(bor(lshift(floor(r * a), 16), lshift(floor(g * a), 8), floor(b * a)), 6)
+      return match_end - 1, rgb_hex
+   end
+   function css_fn.hsla(line, i)
+      if #line < i + CSS_HSLA_FN_MINIMUM_LENGTH then
+         return
+      end
+      local h, s, l, a, match_end = line
+         :sub(i)
+         :match "^hsla%(%s*(%d+)%s*,%s*(%d+)%%%s*,%s*(%d+)%%%s*,%s*([.%d]+)%s*%)()"
+      if not match_end then
+         return
+      end
+      a = tonumber(a)
+      if not a or a > 1 then
+         return
+      end
+      h = tonumber(h)
+      if h > 360 then
+         return
+      end
+      s = tonumber(s)
+      if s > 100 then
+         return
+      end
+      l = tonumber(l)
+      if l > 100 then
+         return
+      end
+      local r, g, b = hsl_to_rgb(h / 360, s / 100, l / 100)
+      if r == nil or g == nil or b == nil then
+         return
+      end
+      local rgb_hex = tohex(bor(lshift(floor(r * a), 16), lshift(floor(g * a), 8), floor(b * a)), 6)
+      return match_end - 1, rgb_hex
+   end
 end
 local css_function_parser, rgb_function_parser, hsl_function_parser
 do
-	local CSS_FUNCTION_TRIE = Trie {'rgb', 'rgba', 'hsl', 'hsla'}
-	local RGB_FUNCTION_TRIE = Trie {'rgb', 'rgba'}
-	local HSL_FUNCTION_TRIE = Trie {'hsl', 'hsla'}
-	css_function_parser = function(line, i)
-		local prefix = CSS_FUNCTION_TRIE:longest_prefix(line:sub(i))
-		if prefix then
-			return css_fn[prefix](line, i)
-		end
-	end
-	rgb_function_parser = function(line, i)
-		local prefix = RGB_FUNCTION_TRIE:longest_prefix(line:sub(i))
-		if prefix then
-			return css_fn[prefix](line, i)
-		end
-	end
-	hsl_function_parser = function(line, i)
-		local prefix = HSL_FUNCTION_TRIE:longest_prefix(line:sub(i))
-		if prefix then
-			return css_fn[prefix](line, i)
-		end
-	end
+   local CSS_FUNCTION_TRIE = Trie { "rgb", "rgba", "hsl", "hsla" }
+   local RGB_FUNCTION_TRIE = Trie { "rgb", "rgba" }
+   local HSL_FUNCTION_TRIE = Trie { "hsl", "hsla" }
+   css_function_parser = function(line, i)
+      local prefix = CSS_FUNCTION_TRIE:longest_prefix(line:sub(i))
+      if prefix then
+         return css_fn[prefix](line, i)
+      end
+   end
+   rgb_function_parser = function(line, i)
+      local prefix = RGB_FUNCTION_TRIE:longest_prefix(line:sub(i))
+      if prefix then
+         return css_fn[prefix](line, i)
+      end
+   end
+   hsl_function_parser = function(line, i)
+      local prefix = HSL_FUNCTION_TRIE:longest_prefix(line:sub(i))
+      if prefix then
+         return css_fn[prefix](line, i)
+      end
+   end
 end
 
 local function compile_matcher(matchers)
-	local parse_fn = matchers[1]
-	for j = 2, #matchers do
-		local old_parse_fn = parse_fn
-		local new_parse_fn = matchers[j]
-		parse_fn = function(line, i)
-			local length, rgb_hex = new_parse_fn(line, i)
-			if length then return length, rgb_hex end
-			return old_parse_fn(line, i)
-		end
-	end
-	return parse_fn
+   local parse_fn = matchers[1]
+   for j = 2, #matchers do
+      local old_parse_fn = parse_fn
+      local new_parse_fn = matchers[j]
+      parse_fn = function(line, i)
+         local length, rgb_hex = new_parse_fn(line, i)
+         if length then
+            return length, rgb_hex
+         end
+         return old_parse_fn(line, i)
+      end
+   end
+   return parse_fn
 end
 
 --- Default namespace used in `highlight_buffer` and `attach_to_buffer`.
@@ -328,123 +460,131 @@ end
 local DEFAULT_NAMESPACE = nvim.create_namespace "colorizer"
 local HIGHLIGHT_NAME_PREFIX = "colorizer"
 local HIGHLIGHT_MODE_NAMES = {
-	background = "mb";
-	foreground = "mf";
+   background = "mb",
+   foreground = "mf",
+   virtualtext = "mv",
 }
 local HIGHLIGHT_CACHE = {}
 
 --- Make a deterministic name for a highlight given these attributes
 local function make_highlight_name(rgb, mode)
-	return table.concat({HIGHLIGHT_NAME_PREFIX, HIGHLIGHT_MODE_NAMES[mode], rgb}, '_')
+   return table.concat({ HIGHLIGHT_NAME_PREFIX, HIGHLIGHT_MODE_NAMES[mode], rgb }, "_")
 end
 
 local function create_highlight(rgb_hex, options)
-	local mode = options.mode or 'background'
-	-- TODO validate rgb format?
-	rgb_hex = rgb_hex:lower()
-	local cache_key = table.concat({HIGHLIGHT_MODE_NAMES[mode], rgb_hex}, "_")
-	local highlight_name = HIGHLIGHT_CACHE[cache_key]
-	-- Look up in our cache.
-	if not highlight_name then
-		if #rgb_hex == 3 then
-			rgb_hex = table.concat {
-				rgb_hex:sub(1,1):rep(2);
-				rgb_hex:sub(2,2):rep(2);
-				rgb_hex:sub(3,3):rep(2);
-			}
-		end
-		-- Create the highlight
-		highlight_name = make_highlight_name(rgb_hex, mode)
-		if mode == 'foreground' then
-			nvim.ex.highlight(highlight_name, "guifg=#"..rgb_hex)
-		else
-			local r, g, b = rgb_hex:sub(1,2), rgb_hex:sub(3,4), rgb_hex:sub(5,6)
-			r, g, b = tonumber(r,16), tonumber(g,16), tonumber(b,16)
-			local fg_color
-			if color_is_bright(r,g,b) then
-				fg_color = "Black"
-			else
-				fg_color = "White"
-			end
-			nvim.ex.highlight(highlight_name, "guifg="..fg_color, "guibg=#"..rgb_hex)
-		end
-		HIGHLIGHT_CACHE[cache_key] = highlight_name
-	end
-	return highlight_name
+   local mode = options.mode or "background"
+   -- TODO validate rgb format?
+   rgb_hex = rgb_hex:lower()
+   local cache_key = table.concat({ HIGHLIGHT_MODE_NAMES[mode], rgb_hex }, "_")
+   local highlight_name = HIGHLIGHT_CACHE[cache_key]
+   -- Look up in our cache.
+   if not highlight_name then
+      if #rgb_hex == 3 then
+         rgb_hex = table.concat {
+            rgb_hex:sub(1, 1):rep(2),
+            rgb_hex:sub(2, 2):rep(2),
+            rgb_hex:sub(3, 3):rep(2),
+         }
+      end
+      -- Create the highlight
+      highlight_name = make_highlight_name(rgb_hex, mode)
+      if mode == "foreground" then
+         nvim.ex.highlight(highlight_name, "guifg=#" .. rgb_hex)
+      else
+         local r, g, b = rgb_hex:sub(1, 2), rgb_hex:sub(3, 4), rgb_hex:sub(5, 6)
+         r, g, b = tonumber(r, 16), tonumber(g, 16), tonumber(b, 16)
+         local fg_color
+         if color_is_bright(r, g, b) then
+            fg_color = "Black"
+         else
+            fg_color = "White"
+         end
+         nvim.ex.highlight(highlight_name, "guifg=" .. fg_color, "guibg=#" .. rgb_hex)
+      end
+      HIGHLIGHT_CACHE[cache_key] = highlight_name
+   end
+   return highlight_name
 end
 
 local MATCHER_CACHE = {}
 local function make_matcher(options)
-	local enable_names		= options.css or options.names
-	local enable_RGB			= options.css or options.RGB
-	local enable_RRGGBB		= options.css or options.RRGGBB
-	local enable_RRGGBBAA = options.css or options.RRGGBBAA
-	local enable_rgb			= options.css or options.css_fns or options.rgb_fn
-	local enable_hsl			= options.css or options.css_fns or options.hsl_fn
-
-	local matcher_key = bor(
-		lshift(enable_names		 and 1 or 0, 0),
-		lshift(enable_RGB			 and 1 or 0, 1),
-		lshift(enable_RRGGBB	 and 1 or 0, 2),
-		lshift(enable_RRGGBBAA and 1 or 0, 3),
-		lshift(enable_rgb			 and 1 or 0, 4),
-		lshift(enable_hsl			 and 1 or 0, 5))
-
-	if matcher_key == 0 then return end
-
-	local loop_parse_fn = MATCHER_CACHE[matcher_key]
-	if loop_parse_fn then
-		return loop_parse_fn
-	end
-
-	local loop_matchers = {}
-	if enable_names then
-		table.insert(loop_matchers, color_name_parser)
-	end
-	do
-		local valid_lengths = {[3] = enable_RGB, [6] = enable_RRGGBB, [8] = enable_RRGGBBAA}
-		local minlen, maxlen
-		for k, v in pairs(valid_lengths) do
-			if v then
-				minlen = minlen and min(k, minlen) or k
-				maxlen = maxlen and max(k, maxlen) or k
-			end
-		end
-		if minlen then
-			table.insert(loop_matchers, function(line, i)
-				local length, rgb_hex = rgb_hex_parser(line, i, minlen, maxlen)
-				if length and valid_lengths[length-1] then
-					return length, rgb_hex
-				end
-			end)
-		end
-	end
-	if enable_rgb and enable_hsl then
-		table.insert(loop_matchers, css_function_parser)
-	elseif enable_rgb then
-		table.insert(loop_matchers, rgb_function_parser)
-	elseif enable_hsl then
-		table.insert(loop_matchers, hsl_function_parser)
-	end
-	loop_parse_fn = compile_matcher(loop_matchers)
-	MATCHER_CACHE[matcher_key] = loop_parse_fn
-	return loop_parse_fn
+   local enable_names = options.css or options.names
+   local enable_RGB = options.css or options.RGB
+   local enable_RRGGBB = options.css or options.RRGGBB
+   local enable_RRGGBBAA = options.css or options.RRGGBBAA
+   local enable_AARRGGBB = options.AARRGGBB
+   local enable_rgb = options.css or options.css_fns or options.rgb_fn
+   local enable_hsl = options.css or options.css_fns or options.hsl_fn
+
+   local matcher_key = bor(
+      lshift(enable_names and 1 or 0, 0),
+      lshift(enable_RGB and 1 or 0, 1),
+      lshift(enable_RRGGBB and 1 or 0, 2),
+      lshift(enable_RRGGBBAA and 1 or 0, 3),
+      lshift(enable_rgb and 1 or 0, 4),
+      lshift(enable_hsl and 1 or 0, 5)
+   )
+
+   if matcher_key == 0 then
+      return
+   end
+
+   local loop_parse_fn = MATCHER_CACHE[matcher_key]
+   if loop_parse_fn then
+      return loop_parse_fn
+   end
+
+   local loop_matchers = {}
+   if enable_names then
+      table.insert(loop_matchers, color_name_parser)
+   end
+   if enable_AARRGGBB then
+      table.insert(loop_matchers, rgb_0x_parser)
+   end
+   do
+      local valid_lengths = { [3] = enable_RGB, [6] = enable_RRGGBB, [8] = enable_RRGGBBAA }
+      local minlen, maxlen
+      for k, v in pairs(valid_lengths) do
+         if v then
+            minlen = minlen and min(k, minlen) or k
+            maxlen = maxlen and max(k, maxlen) or k
+         end
+      end
+      if minlen then
+         table.insert(loop_matchers, function(line, i)
+            local length, rgb_hex = rgb_hex_parser(line, i, minlen, maxlen)
+            if length and valid_lengths[length - 1] then
+               return length, rgb_hex
+            end
+         end)
+      end
+   end
+   if enable_rgb and enable_hsl then
+      table.insert(loop_matchers, css_function_parser)
+   elseif enable_rgb then
+      table.insert(loop_matchers, rgb_function_parser)
+   elseif enable_hsl then
+      table.insert(loop_matchers, hsl_function_parser)
+   end
+   loop_parse_fn = compile_matcher(loop_matchers)
+   MATCHER_CACHE[matcher_key] = loop_parse_fn
+   return loop_parse_fn
 end
 
 local function add_highlight(options, buf, ns, data)
-	for linenr, hls in pairs(data) do
-		if vim.tbl_contains({'foreground', 'background'}, options.mode) then
-			for _, hl in ipairs(hls) do
-				nvim_buf_add_highlight(buf, ns, hl.name, linenr, hl.range[1], hl.range[2])
-			end
-		elseif options.mode == 'virtualtext' then
-			local chunks = {}
-			for _, hl in ipairs(hls) do
-				table.insert(chunks, {options.virtualtext, hl.name})
-			end
-			nvim_buf_set_virtual_text(buf, ns, linenr, chunks, {})
-		end
-	end
+   for linenr, hls in pairs(data) do
+      if vim.tbl_contains({ "foreground", "background" }, options.mode) then
+         for _, hl in ipairs(hls) do
+            nvim_buf_add_highlight(buf, ns, hl.name, linenr, hl.range[1], hl.range[2])
+         end
+      elseif options.mode == "virtualtext" then
+         local chunks = {}
+         for _, hl in ipairs(hls) do
+            table.insert(chunks, { options.virtualtext, hl.name })
+         end
+         nvim_buf_set_virtual_text(buf, ns, linenr, chunks, {})
+      end
+   end
 end
 
 --[[-- Highlight the buffer region.
@@ -459,30 +599,30 @@ buffer `buf` and attach it to the namespace `ns`.
 @see setup
 ]]
 local function highlight_buffer(buf, ns, lines, line_start, options)
-	-- TODO do I have to put this here?
-	initialize_trie()
-	ns = ns or DEFAULT_NAMESPACE
-	local loop_parse_fn = make_matcher(options)
-	local data = {}
-	local mode = options.mode == 'background' and {mode='background'} or {mode='foreground'}
-	for current_linenum, line in ipairs(lines) do
-		current_linenum = current_linenum - 1 + line_start
-		-- Upvalues are options and current_linenum
-		local i = 1
-		while i < #line do
-			local length, rgb_hex = loop_parse_fn(line, i)
-			if length then
-				local name = create_highlight(rgb_hex, mode)
-				local d = data[current_linenum] or {}
-				table.insert(d, {name=name, range={i-1, i+length-1}})
-				data[current_linenum] = d
-				i = i + length
-			else
-				i = i + 1
-			end
-		end
-	end
-	add_highlight(options, buf, ns, data)
+   -- TODO do I have to put this here?
+   initialize_trie()
+   ns = ns or DEFAULT_NAMESPACE
+   local loop_parse_fn = make_matcher(options)
+   local data = {}
+   local mode = options.mode == "background" and { mode = "background" } or { mode = "foreground" }
+   for current_linenum, line in ipairs(lines) do
+      current_linenum = current_linenum - 1 + line_start
+      -- Upvalues are options and current_linenum
+      local i = 1
+      while i < #line do
+         local length, rgb_hex = loop_parse_fn(line, i)
+         if length then
+            local name = create_highlight(rgb_hex, mode)
+            local d = data[current_linenum] or {}
+            table.insert(d, { name = name, range = { i - 1, i + length - 1 } })
+            data[current_linenum] = d
+            i = i + length
+         else
+            i = i + 1
+         end
+      end
+   end
+   add_highlight(options, buf, ns, data)
 end
 
 ---
@@ -490,36 +630,36 @@ end
 ---
 
 local SETUP_SETTINGS = {
-	exclusions = {};
-	default_options = DEFAULT_OPTIONS;
+   exclusions = {},
+   default_options = DEFAULT_OPTIONS,
 }
 local BUFFER_OPTIONS = {}
 local FILETYPE_OPTIONS = {}
 
 local function rehighlight_buffer(buf, options)
-	local ns = DEFAULT_NAMESPACE
-	if buf == 0 or buf == nil then
-		buf = nvim_get_current_buf()
-	end
-	assert(options)
-	nvim_buf_clear_namespace(buf, ns, 0, -1)
-	local lines = nvim_buf_get_lines(buf, 0, -1, true)
-	highlight_buffer(buf, ns, lines, 0, options)
+   local ns = DEFAULT_NAMESPACE
+   if buf == 0 or buf == nil then
+      buf = nvim_get_current_buf()
+   end
+   assert(options)
+   nvim_buf_clear_namespace(buf, ns, 0, -1)
+   local lines = nvim_buf_get_lines(buf, 0, -1, true)
+   highlight_buffer(buf, ns, lines, 0, options)
 end
 
 local function new_buffer_options(buf)
-	local filetype = nvim.buf_get_option(buf, 'filetype')
-	return FILETYPE_OPTIONS[filetype] or SETUP_SETTINGS.default_options
+   local filetype = nvim.buf_get_option(buf, "filetype")
+   return FILETYPE_OPTIONS[filetype] or SETUP_SETTINGS.default_options
 end
 
 --- Check if attached to a buffer.
 -- @tparam[opt=0|nil] integer buf A value of 0 implies the current buffer.
 -- @return true if attached to the buffer, false otherwise.
 local function is_buffer_attached(buf)
-	if buf == 0 or buf == nil then
-		buf = nvim_get_current_buf()
-	end
-	return BUFFER_OPTIONS[buf] ~= nil
+   if buf == 0 or buf == nil then
+      buf = nvim_get_current_buf()
+   end
+   return BUFFER_OPTIONS[buf] ~= nil
 end
 
 --- Attach to a buffer and continuously highlight changes.
@@ -527,48 +667,47 @@ end
 -- @param[opt] options Configuration options as described in `setup`
 -- @see setup
 local function attach_to_buffer(buf, options)
-	if buf == 0 or buf == nil then
-		buf = nvim_get_current_buf()
-	end
-	local already_attached = BUFFER_OPTIONS[buf] ~= nil
-	local ns = DEFAULT_NAMESPACE
-	if not options then
-		options = new_buffer_options(buf)
-	end
-	BUFFER_OPTIONS[buf] = options
-	rehighlight_buffer(buf, options)
-	if already_attached then
-		return
-	end
-	-- send_buffer: true doesn't actually do anything in Lua (yet)
-	nvim.buf_attach(buf, false, {
-		on_lines = function(event_type, buf, changed_tick, firstline, lastline, new_lastline)
-			-- This is used to signal stopping the handler highlights
-			if not BUFFER_OPTIONS[buf] then
-				return true
-			end
-			nvim_buf_clear_namespace(buf, ns, firstline, new_lastline)
-			local lines = nvim_buf_get_lines(buf, firstline, new_lastline, false)
-			highlight_buffer(buf, ns, lines, firstline, BUFFER_OPTIONS[buf])
-		end;
-		on_detach = function()
-			BUFFER_OPTIONS[buf] = nil
-		end;
-	})
+   if buf == 0 or buf == nil then
+      buf = nvim_get_current_buf()
+   end
+   local already_attached = BUFFER_OPTIONS[buf] ~= nil
+   local ns = DEFAULT_NAMESPACE
+   if not options then
+      options = new_buffer_options(buf)
+   end
+   BUFFER_OPTIONS[buf] = options
+   rehighlight_buffer(buf, options)
+   if already_attached then
+      return
+   end
+   -- send_buffer: true doesn't actually do anything in Lua (yet)
+   nvim.buf_attach(buf, false, {
+      on_lines = function(event_type, buf, changed_tick, firstline, lastline, new_lastline)
+         -- This is used to signal stopping the handler highlights
+         if not BUFFER_OPTIONS[buf] then
+            return true
+         end
+         nvim_buf_clear_namespace(buf, ns, firstline, new_lastline)
+         local lines = nvim_buf_get_lines(buf, firstline, new_lastline, false)
+         highlight_buffer(buf, ns, lines, firstline, BUFFER_OPTIONS[buf])
+      end,
+      on_detach = function()
+         BUFFER_OPTIONS[buf] = nil
+      end,
+   })
 end
 
 --- Stop highlighting the current buffer.
 -- @tparam[opt=0|nil] integer buf A value of 0 or nil implies the current buffer.
 -- @tparam[opt=DEFAULT_NAMESPACE] integer ns the namespace id.
 local function detach_from_buffer(buf, ns)
-	if buf == 0 or buf == nil then
-		buf = nvim_get_current_buf()
-	end
-	nvim_buf_clear_namespace(buf, ns or DEFAULT_NAMESPACE, 0, -1)
-	BUFFER_OPTIONS[buf] = nil
+   if buf == 0 or buf == nil then
+      buf = nvim_get_current_buf()
+   end
+   nvim_buf_clear_namespace(buf, ns or DEFAULT_NAMESPACE, 0, -1)
+   BUFFER_OPTIONS[buf] = nil
 end
 
-
 --- Easy to use function if you want the full setup without fine grained control.
 -- Setup an autocmd which enables colorizing for the filetypes and options specified.
 --
@@ -589,82 +728,84 @@ end
 -- @tparam[opt] {[string]=string} default_options Default options to apply for the filetypes enable.
 -- @usage require'colorizer'.setup()
 local function setup(filetypes, user_default_options)
-	if not nvim.o.termguicolors then
-		nvim.err_writeln("&termguicolors must be set")
-		return
-	end
-	FILETYPE_OPTIONS = {}
-	SETUP_SETTINGS = {
-		exclusions = {};
-		default_options = merge(DEFAULT_OPTIONS, user_default_options or {});
-	}
-	-- Initialize this AFTER setting COLOR_NAME_SETTINGS
-	initialize_trie()
-	function COLORIZER_SETUP_HOOK()
-		local filetype = nvim.bo.filetype
-		if SETUP_SETTINGS.exclusions[filetype] then
-			return
-		end
-		local options = FILETYPE_OPTIONS[filetype] or SETUP_SETTINGS.default_options
-		attach_to_buffer(nvim_get_current_buf(), options)
-	end
-	nvim.ex.augroup("ColorizerSetup")
-	nvim.ex.autocmd_()
-	if not filetypes then
-		nvim.ex.autocmd("FileType * lua COLORIZER_SETUP_HOOK()")
-	else
-		for k, v in pairs(filetypes) do
-			local filetype
-			local options = SETUP_SETTINGS.default_options
-			if type(k) == 'string' then
-				filetype = k
-				if type(v) ~= 'table' then
-					nvim.err_writeln("colorizer: Invalid option type for filetype "..filetype)
-				else
-					options = merge(SETUP_SETTINGS.default_options, v)
-					assert(HIGHLIGHT_MODE_NAMES[options.mode or 'background'], "colorizer: Invalid mode: "..tostring(options.mode))
-				end
-			else
-				filetype = v
-			end
-			-- Exclude
-			if filetype:sub(1,1) == '!' then
-				SETUP_SETTINGS.exclusions[filetype:sub(2)] = true
-			else
-				FILETYPE_OPTIONS[filetype] = options
-				-- TODO What's the right mode for this? BufEnter?
-				nvim.ex.autocmd("FileType", filetype, "lua COLORIZER_SETUP_HOOK()")
-			end
-		end
-	end
-	nvim.ex.augroup("END")
+   if not nvim.o.termguicolors then
+      nvim.err_writeln "&termguicolors must be set"
+      return
+   end
+   FILETYPE_OPTIONS = {}
+   SETUP_SETTINGS = {
+      exclusions = {},
+      default_options = merge(DEFAULT_OPTIONS, user_default_options or {}),
+   }
+   -- Initialize this AFTER setting COLOR_NAME_SETTINGS
+   initialize_trie()
+   function COLORIZER_SETUP_HOOK()
+      local filetype = nvim.bo.filetype
+      if SETUP_SETTINGS.exclusions[filetype] then
+         return
+      end
+      local options = FILETYPE_OPTIONS[filetype] or SETUP_SETTINGS.default_options
+      attach_to_buffer(nvim_get_current_buf(), options)
+   end
+   nvim.ex.augroup "ColorizerSetup"
+   nvim.ex.autocmd_()
+   if not filetypes then
+      nvim.ex.autocmd "FileType * lua COLORIZER_SETUP_HOOK()"
+   else
+      for k, v in pairs(filetypes) do
+         local filetype
+         local options = SETUP_SETTINGS.default_options
+         if type(k) == "string" then
+            filetype = k
+            if type(v) ~= "table" then
+               nvim.err_writeln("colorizer: Invalid option type for filetype " .. filetype)
+            else
+               options = merge(SETUP_SETTINGS.default_options, v)
+               assert(
+                  HIGHLIGHT_MODE_NAMES[options.mode or "background"],
+                  "colorizer: Invalid mode: " .. tostring(options.mode)
+               )
+            end
+         else
+            filetype = v
+         end
+         -- Exclude
+         if filetype:sub(1, 1) == "!" then
+            SETUP_SETTINGS.exclusions[filetype:sub(2)] = true
+         else
+            FILETYPE_OPTIONS[filetype] = options
+            -- TODO What's the right mode for this? BufEnter?
+            nvim.ex.autocmd("FileType", filetype, "lua COLORIZER_SETUP_HOOK()")
+         end
+      end
+   end
+   nvim.ex.augroup "END"
 end
 
 --- Reload all of the currently active highlighted buffers.
 local function reload_all_buffers()
-	for buf, buffer_options in pairs(BUFFER_OPTIONS) do
-		attach_to_buffer(buf)
-	end
+   for buf, buffer_options in pairs(BUFFER_OPTIONS) do
+      attach_to_buffer(buf)
+   end
 end
 
 --- Return the currently active buffer options.
 -- @tparam[opt=0|nil] integer buf A value of 0 or nil implies the current buffer.
 local function get_buffer_options(buf)
-	if buf == 0 or buf == nil then
-		buf = nvim_get_current_buf()
-	end
-	return merge({}, BUFFER_OPTIONS[buf])
+   if buf == 0 or buf == nil then
+      buf = nvim_get_current_buf()
+   end
+   return merge({}, BUFFER_OPTIONS[buf])
 end
 
 --- @export
 return {
-	DEFAULT_NAMESPACE = DEFAULT_NAMESPACE;
-	setup = setup;
-	is_buffer_attached = is_buffer_attached;
-	attach_to_buffer = attach_to_buffer;
-	detach_from_buffer = detach_from_buffer;
-	highlight_buffer = highlight_buffer;
-	reload_all_buffers = reload_all_buffers;
-	get_buffer_options = get_buffer_options;
+   DEFAULT_NAMESPACE = DEFAULT_NAMESPACE,
+   setup = setup,
+   is_buffer_attached = is_buffer_attached,
+   attach_to_buffer = attach_to_buffer,
+   detach_from_buffer = detach_from_buffer,
+   highlight_buffer = highlight_buffer,
+   reload_all_buffers = reload_all_buffers,
+   get_buffer_options = get_buffer_options,
 }
-