Prepare for more color functions

Author: FlorianRappl

CHANGELOG.md

@@ -14,6 +14,7 @@ Released on tbd.
 - Added support for 8-digit hex color codes (#132)
 - Added more CSSOM possibilities and helpers (#6)
 - Added parts of recent color spec update such as `rgb` with spaces (#131)
+- Added now Color L4 parsing with `hsl`, `hwb`, `lab`, `lch`, `oklab`, and `oklch`
 
 # 0.17.0
 

src/AngleSharp.Css/Constants/FunctionNames.cs

@@ -262,6 +262,26 @@ public static class FunctionNames
         /// </summary>
         public static readonly String Hwba = "hwba";
 
+        /// <summary>
+        /// The LAB (Lightness, A-axis, B-axis) function.
+        /// </summary>
+        public static readonly String Lab = "lab";
+
+        /// <summary>
+        /// The LCH (Lightness, Chroma, Hue) function.
+        /// </summary>
+        public static readonly String Lch = "lch";
+
+        /// <summary>
+        /// The Oklab (Lightness, A-axis, B-axis) function.
+        /// </summary>
+        public static readonly String Oklab = "oklab";
+
+        /// <summary>
+        /// The Oklch (Lightness, Chroma, Hue) function.
+        /// </summary>
+        public static readonly String Oklch = "oklch";
+
         /// <summary>
         /// The content function.
         /// </summary>

src/AngleSharp.Css/Parser/Micro/ColorParser.cs

@@ -21,6 +21,10 @@ static class ColorParser
             { FunctionNames.Gray, ParseGray },
             { FunctionNames.Hwb, ParseHwba },
             { FunctionNames.Hwba, ParseHwba },
+            { FunctionNames.Lab, ParseLab },
+            { FunctionNames.Lch, ParseLch },
+            { FunctionNames.Oklab, ParseOklab},
+            { FunctionNames.Oklch, ParseOklch },
         };
 
         /// <summary>
@@ -221,6 +225,35 @@ static class ColorParser
             return null;
         }
 
+        private static Color? ParseLab(StringSource source)
+        {
+            // lab(50% 40 59.5)
+            // lab(50 % 40 59.5 / 0.5)
+            return null;
+        }
+
+        private static Color? ParseLch(StringSource source)
+        {
+            // lch(52.2% 72.2 50)
+            // lch(52.2 % 72.2 50 / 0.5)
+            return null;
+        }
+
+
+        private static Color? ParseOklab(StringSource source)
+        {
+            // oklab(59% 0.1 0.1)
+            // oklab(59 % 0.1 0.1 / 0.5)
+            return null;
+        }
+
+        private static Color? ParseOklch(StringSource source)
+        {
+            // oklch(60% 0.15 50)
+            // oklch(60 % 0.15 50 / 0.5)
+            return null;
+        }
+
         private static Color? ParseHwba(StringSource source)
         {
             var h = ParseAngle(source);