Consolidation and type improvements

src/AngleSharp.Css/Converters/CounterValueConverter.cs

@@ -9,6 +9,8 @@ namespace AngleSharp.Css.Converters
 
     sealed class CounterValueConverter : IValueConverter
     {
+        private static readonly CounterValue[] NoneValue = new CounterValue[0];
+
         private readonly Int32 _defaultValue;
 
         public CounterValueConverter(Int32 defaultValue)
@@ -18,7 +20,7 @@ namespace AngleSharp.Css.Converters
 
         public ICssValue Convert(StringSource source)
         {
-            var counters = new List<ICssValue>();
+            var counters = new List<CounterValue>();
 
             if (!source.IsIdentifier(CssKeywords.None))
             {
@@ -37,10 +39,10 @@ namespace AngleSharp.Css.Converters
                     counters.Add(new CounterValue(name, value));
                 }
 
-                return new CssCountersValue(counters.ToArray());
+                return new CssTupleValue<CounterValue>(counters.ToArray());
             }
 
-            return new CssCountersValue();
+            return new Constant<CounterValue[]>(CssKeywords.None, NoneValue);
         }
     }
 }

src/AngleSharp.Css/Converters/ValueConverterExtensions.cs

@@ -27,25 +27,17 @@ namespace AngleSharp.Css.Converters
             return varRefs;
         }
 
-        public static IValueConverter Many(this IValueConverter converter, Int32 min = 1, Int32 max = UInt16.MaxValue, String separator = null)
-        {
-            return new OneOrMoreValueConverter(converter, min, max, separator);
-        }
+        public static IValueConverter Many(this IValueConverter converter, Int32 min = 1, Int32 max = UInt16.MaxValue, String separator = null) =>
+            new OneOrMoreValueConverter(converter, min, max, separator);
 
-        public static IValueConverter FromList(this IValueConverter converter)
-        {
-            return new ListValueConverter(converter);
-        }
+        public static IValueConverter FromList(this IValueConverter converter) =>
+            new ListValueConverter(converter);
 
-        public static IValueConverter ToConverter<T>(this Dictionary<String, T> values)
-        {
-            return new DictionaryValueConverter<T>(values);
-        }
+        public static IValueConverter ToConverter<T>(this Dictionary<String, T> values) =>
+            new DictionaryValueConverter<T>(values);
 
-        public static IValueConverter Periodic(this IValueConverter converter)
-        {
-            return new PeriodicValueConverter(converter);
-        }
+        public static IValueConverter Periodic(this IValueConverter converter) =>
+            new PeriodicValueConverter(converter);
 
         public static IValueConverter Exclusive(this IValueConverter converter)
         {
@@ -65,17 +57,14 @@ namespace AngleSharp.Css.Converters
             });
         }
 
-        public static IValueConverter Option(this IValueConverter converter)
-        {
-            return new OptionValueConverter<Object>(converter, null);
-        }
+        public static IValueConverter Option(this IValueConverter converter) =>
+            new OptionValueConverter<Object>(converter, null);
 
-        public static IValueConverter Option<T>(this IValueConverter converter, T defaultValue)
-        {
-            return new OptionValueConverter<T>(converter, defaultValue);
-        }
+        public static IValueConverter Option<T>(this IValueConverter converter, T defaultValue) =>
+            new OptionValueConverter<T>(converter, defaultValue);
 
-        public static String Join(this ICssValue[] values, String separator)
+        public static String Join<T>(this T[] values, String separator)
+            where T : ICssValue
         {
             var buffer = StringBuilderPool.Obtain();
             var previous = false;
@@ -98,29 +87,5 @@ namespace AngleSharp.Css.Converters
 
             return buffer.ToPool();
         }
-
-        public static String Join<T>(this T[] values, String separator)
-        {
-            var buffer = StringBuilderPool.Obtain();
-            var previous = false;
-
-            for (var i = 0; i < values.Length; i++)
-            {
-                var str = values[i].ToString();
-
-                if (!String.IsNullOrEmpty(str))
-                {
-                    if (previous)
-                    {
-                        buffer.Append(separator);
-                    }
-
-                    buffer.Append(str);
-                    previous = true;
-                }
-            }
-
-            return buffer.ToPool();
-        }
     }
 }

src/AngleSharp.Css/Values/Multiples/CssCountersValue.cs

@@ -1,56 +0,0 @@
-namespace AngleSharp.Css.Values
-{
-    using AngleSharp.Css.Converters;
-    using AngleSharp.Css.Dom;
-    using System;
-    using System.Collections;
-    using System.Collections.Generic;
-    using System.Linq;
-
-    /// <summary>
-    /// Represents the CSS counters definition.
-    /// </summary>
-    class CssCountersValue : ICssMultipleValue
-    {
-        #region Fields
-
-        private readonly ICssValue[] _counters;
-
-        #endregion
-
-        #region ctor
-        
-        public CssCountersValue()
-        {
-            _counters = null;
-        }
-        
-        public CssCountersValue(ICssValue[] counters)
-        {
-            _counters = counters;
-        }
-
-        public ICssValue this[Int32 index] => _counters[index];
-
-        #endregion
-
-        #region Properties
-        
-        public ICssValue[] Values => _counters;
-        
-        public String CssText => _counters != null ? _counters.Join(" ") : CssKeywords.None;
-
-        public Int32 Count => _counters.Length;
-
-        #endregion
-
-        #region Methods
-
-        IEnumerator<ICssValue> IEnumerable<ICssValue>.GetEnumerator() =>
-            _counters.AsEnumerable().GetEnumerator();
-
-        IEnumerator IEnumerable.GetEnumerator() => _counters.GetEnumerator();
-
-        #endregion
-    }
-}

src/AngleSharp.Css/Values/Multiples/CssListValue.cs

@@ -10,17 +10,18 @@ namespace AngleSharp.Css.Values
     /// <summary>
     /// Represents a CSS value list.
     /// </summary>
-    class CssListValue : ICssMultipleValue
+    class CssListValue<T> : ICssMultipleValue
+        where T : ICssValue
     {
         #region Fields
 
-        private readonly ICssValue[] _items;
+        private readonly T[] _items;
 
         #endregion
 
         #region ctor
 
-        public CssListValue(ICssValue[] items)
+        public CssListValue(T[] items)
         {
             _items = items;
         }
@@ -31,8 +32,8 @@ namespace AngleSharp.Css.Values
 
         public ICssValue this[Int32 index] => _items[index];
 
-        public ICssValue[] Items => _items;
-        
+        public T[] Items => _items;
+
         public String CssText => _items.Join(", ");
 
         public Int32 Count => _items.Length;
@@ -42,10 +43,25 @@ namespace AngleSharp.Css.Values
         #region Methods
 
         IEnumerator<ICssValue> IEnumerable<ICssValue>.GetEnumerator() =>
-            _items.AsEnumerable().GetEnumerator();
+            _items.OfType<ICssValue>().GetEnumerator();
 
         IEnumerator IEnumerable.GetEnumerator() => _items.GetEnumerator();
 
         #endregion
     }
+
+    /// <summary>
+    /// Represents a CSS value list.
+    /// </summary>
+    class CssListValue : CssListValue<ICssValue>
+    {
+        #region ctor
+
+        public CssListValue(ICssValue[] items)
+            : base(items)
+        {
+        }
+
+        #endregion
+    }
 }

src/AngleSharp.Css/Values/Multiples/CssTupleValue.cs

@@ -10,20 +10,21 @@ namespace AngleSharp.Css.Values
     /// <summary>
     /// Represents a tuple of CSS values.
     /// </summary>
-    class CssTupleValue : ICssMultipleValue
+    class CssTupleValue<T> : ICssMultipleValue
+        where T : ICssValue
     {
         #region Fields
 
-        private readonly ICssValue[] _items;
+        private readonly T[] _items;
         private readonly String _separator;
 
         #endregion
 
         #region ctor
-        
-        public CssTupleValue(ICssValue[] items, String separator = null)
+
+        public CssTupleValue(T[] items = null, String separator = null)
         {
-            _items = items;
+            _items = items ?? new T[0];
             _separator = separator ?? " ";
         }
 
@@ -33,7 +34,7 @@ namespace AngleSharp.Css.Values
 
         public ICssValue this[Int32 index] => _items[index];
 
-        public ICssValue[] Items => _items;
+        public T[] Items => _items;
 
         public String Separator => _separator;
 
@@ -46,10 +47,25 @@ namespace AngleSharp.Css.Values
         #region Methods
 
         IEnumerator<ICssValue> IEnumerable<ICssValue>.GetEnumerator() =>
-            _items.AsEnumerable().GetEnumerator();
+            _items.OfType<ICssValue>().GetEnumerator();
 
         IEnumerator IEnumerable.GetEnumerator() => _items.GetEnumerator();
 
         #endregion
     }
+
+    /// <summary>
+    /// Represents a tuple of CSS values.
+    /// </summary>
+    class CssTupleValue : CssTupleValue<ICssValue>
+    {
+        #region ctor
+        
+        public CssTupleValue(ICssValue[] items = null, String separator = null)
+            : base(items, separator)
+        {
+        }
+
+        #endregion
+    }
 }