From 6f16d57efdf8492d12e034f42cb09a7f74e0c382 Mon Sep 17 00:00:00 2001
From: Emmanuel Hansen <emmausssss@gmail.com>
Date: Wed, 14 Jun 2023 11:31:44 +0000
Subject: [PATCH] andd and and or queries

---
 samples/ControlCatalog/MainView.xaml          |   7 ++
 .../Styling/Activators/AndQueryActivator.cs   |  69 ++++++++++++
 .../Activators/AndQueryActivatorBuilder.cs    |  51 +++++++++
 .../Styling/Activators/OrQueryActivator.cs    |  63 +++++++++++
 .../Activators/OrQueryActivatorBuilder.cs     |  51 +++++++++
 src/Avalonia.Base/Styling/AndQuery.cs         | 100 +++++++++++++++++
 src/Avalonia.Base/Styling/OrQuery.cs          |   7 +-
 src/Avalonia.Base/Styling/Queries.cs          |  20 ++++
 .../AvaloniaXamlIlQueryTransformer.cs         |  94 +++++++++++++++-
 .../Markup/Parsers/MediaQueryGrammar.cs       |  25 ++++-
 .../Markup/Parsers/MediaQueryParser.cs        |  41 +++----
 .../Parsers/QueryGrammarTests.cs              | 104 ++++++++++++++++++
 .../Parsers/QueryParserTests.cs               |  24 ++++
 13 files changed, 620 insertions(+), 36 deletions(-)
 create mode 100644 src/Avalonia.Base/Styling/Activators/AndQueryActivator.cs
 create mode 100644 src/Avalonia.Base/Styling/Activators/AndQueryActivatorBuilder.cs
 create mode 100644 src/Avalonia.Base/Styling/Activators/OrQueryActivator.cs
 create mode 100644 src/Avalonia.Base/Styling/Activators/OrQueryActivatorBuilder.cs
 create mode 100644 src/Avalonia.Base/Styling/AndQuery.cs
 create mode 100644 tests/Avalonia.Markup.UnitTests/Parsers/QueryGrammarTests.cs
 create mode 100644 tests/Avalonia.Markup.UnitTests/Parsers/QueryParserTests.cs

diff --git a/samples/ControlCatalog/MainView.xaml b/samples/ControlCatalog/MainView.xaml
index 9fe0b4d84f..c065fb35f9 100644
--- a/samples/ControlCatalog/MainView.xaml
+++ b/samples/ControlCatalog/MainView.xaml
@@ -14,6 +14,12 @@
                   Value="Red" />
         </Style>
       </Media>
+      <Media Query="width >= 600 and height &lt;= 550 and orientation:portrait">
+        <Style  Selector="TextBlock#Multi">
+          <Setter Property="Foreground"
+                  Value="Red" />
+        </Style>
+      </Media>
       <Media Query="width &lt;= 800">
         <Style  Selector="TextBlock#MaxWidth">
           <Setter Property="Foreground"
@@ -78,6 +84,7 @@
     <StackPanel Spacing="10">
       <TextBlock Name="MinWidth" Classes="h2" Text="width >= 600" />
       <TextBlock Name="MaxWidth" Classes="h2" Text="width &lt;= 800" />
+      <TextBlock Name="Multi" Classes="h2" Text="width >= 600 and height &lt;= 550 and orientation:portrait" />
       <TextBlock Name="MinHeight" Classes="h2" Text="height >= 600" />
       <TextBlock Name="MaxHeight" Classes="h2" Text="height &lt;= 800" />
       <TextBlock Name="Landscape" Classes="h2" Text="orientation:landscape" />
diff --git a/src/Avalonia.Base/Styling/Activators/AndQueryActivator.cs b/src/Avalonia.Base/Styling/Activators/AndQueryActivator.cs
new file mode 100644
index 0000000000..a5f821bf35
--- /dev/null
+++ b/src/Avalonia.Base/Styling/Activators/AndQueryActivator.cs
@@ -0,0 +1,69 @@
+using System.Collections.Generic;
+
+namespace Avalonia.Styling.Activators
+{
+    /// <summary>
+    /// An aggregate <see cref="IStyleActivator"/> which is active when all of its inputs are
+    /// active.
+    /// </summary>
+    internal class AndQueryActivator : MediaQueryActivatorBase, IStyleActivatorSink
+    {
+        private List<IStyleActivator>? _sources;
+
+        public AndQueryActivator(Visual visual) : base(visual)
+        {
+        }
+
+        public int Count => _sources?.Count ?? 0;
+
+        public void Add(IStyleActivator activator)
+        {
+            if (IsSubscribed)
+                throw new AvaloniaInternalException("AndActivator is already subscribed.");
+            _sources ??= new List<IStyleActivator>();
+            _sources.Add(activator);
+        }
+
+        void IStyleActivatorSink.OnNext(bool value) => ReevaluateIsActive();
+
+        protected override bool EvaluateIsActive()
+        {
+            if (_sources is null || _sources.Count == 0)
+                return true;
+
+            var count = _sources.Count;
+            var mask = (1ul << count) - 1;
+            var flags = 0UL;
+
+            for (var i = 0; i < count; ++i)
+            {
+                if (_sources[i].GetIsActive())
+                    flags |= 1ul << i;
+            }
+
+            return flags == mask;
+        }
+
+        protected override void Initialize()
+        {
+            if (_sources is object)
+            {
+                foreach (var source in _sources)
+                {
+                    source.Subscribe(this);
+                }
+            }
+        }
+
+        protected override void Deinitialize()
+        {
+            if (_sources is object)
+            {
+                foreach (var source in _sources)
+                {
+                    source.Unsubscribe(this);
+                }
+            }
+        }
+    }
+}
diff --git a/src/Avalonia.Base/Styling/Activators/AndQueryActivatorBuilder.cs b/src/Avalonia.Base/Styling/Activators/AndQueryActivatorBuilder.cs
new file mode 100644
index 0000000000..dfa8684d93
--- /dev/null
+++ b/src/Avalonia.Base/Styling/Activators/AndQueryActivatorBuilder.cs
@@ -0,0 +1,51 @@
+#nullable enable
+
+namespace Avalonia.Styling.Activators
+{
+    /// <summary>
+    /// Builds an <see cref="AndActivator"/>.
+    /// </summary>
+    /// <remarks>
+    /// When ANDing style activators, if there is more than one input then creates an instance of
+    /// <see cref="AndActivator"/>. If there is only one input, returns the input directly.
+    /// </remarks>
+    internal struct AndQueryActivatorBuilder
+    {
+        private readonly Visual _visual;
+        private IStyleActivator? _single;
+        private AndQueryActivator? _multiple;
+
+        public AndQueryActivatorBuilder(Visual visual) : this()
+        {
+            _visual = visual;
+        }
+
+        public int Count => _multiple?.Count ?? (_single is object ? 1 : 0);
+
+        public void Add(IStyleActivator? activator)
+        {
+            if (activator == null)
+            {
+                return;
+            }
+
+            if (_single is null && _multiple is null)
+            {
+                _single = activator;
+            }
+            else
+            {
+                if (_multiple is null)
+                {
+                    _multiple = new AndQueryActivator(_visual);
+                    _multiple.Add(_single!);
+                    _single = null;
+                }
+
+                _multiple.Add(activator);
+            }
+        }
+
+        public IStyleActivator Get() => _single ?? _multiple!;
+    }
+}
diff --git a/src/Avalonia.Base/Styling/Activators/OrQueryActivator.cs b/src/Avalonia.Base/Styling/Activators/OrQueryActivator.cs
new file mode 100644
index 0000000000..d2dfeee58e
--- /dev/null
+++ b/src/Avalonia.Base/Styling/Activators/OrQueryActivator.cs
@@ -0,0 +1,63 @@
+using System.Collections.Generic;
+
+namespace Avalonia.Styling.Activators
+{
+    /// <summary>
+    /// An aggregate <see cref="IStyleActivator"/> which is active when any of its inputs are
+    /// active.
+    /// </summary>
+    internal class OrQueryActivator : MediaQueryActivatorBase, IStyleActivatorSink
+    {
+        private List<IStyleActivator>? _sources;
+
+        public OrQueryActivator(Visual visual) : base(visual)
+        {
+        }
+
+        public int Count => _sources?.Count ?? 0;
+
+        public void Add(IStyleActivator activator)
+        {
+            _sources ??= new List<IStyleActivator>();
+            _sources.Add(activator);
+        }
+
+        void IStyleActivatorSink.OnNext(bool value) => ReevaluateIsActive();
+
+        protected override bool EvaluateIsActive()
+        {
+            if (_sources is null || _sources.Count == 0)
+                return true;
+
+            foreach (var source in _sources)
+            {
+                if (source.GetIsActive())
+                    return true;
+            }
+
+            return false;
+        }
+
+        protected override void Initialize()
+        {
+            if (_sources is object)
+            {
+                foreach (var source in _sources)
+                {
+                    source.Subscribe(this);
+                }
+            }
+        }
+
+        protected override void Deinitialize()
+        {
+            if (_sources is object)
+            {
+                foreach (var source in _sources)
+                {
+                    source.Unsubscribe(this);
+                }
+            }
+        }
+    }
+}
diff --git a/src/Avalonia.Base/Styling/Activators/OrQueryActivatorBuilder.cs b/src/Avalonia.Base/Styling/Activators/OrQueryActivatorBuilder.cs
new file mode 100644
index 0000000000..0571f0d3c1
--- /dev/null
+++ b/src/Avalonia.Base/Styling/Activators/OrQueryActivatorBuilder.cs
@@ -0,0 +1,51 @@
+#nullable enable
+
+namespace Avalonia.Styling.Activators
+{
+    /// <summary>
+    /// Builds an <see cref="OrActivator"/>.
+    /// </summary>
+    /// <remarks>
+    /// When ORing style activators, if there is more than one input then creates an instance of
+    /// <see cref="OrActivator"/>. If there is only one input, returns the input directly.
+    /// </remarks>
+    internal struct OrQueryActivatorBuilder
+    {
+        private IStyleActivator? _single;
+        private OrQueryActivator? _multiple;
+        private Visual _visual;
+
+        public OrQueryActivatorBuilder(Visual visual) : this()
+        {
+            _visual = visual;
+        }
+
+        public int Count => _multiple?.Count ?? (_single is object ? 1 : 0);
+
+        public void Add(IStyleActivator? activator)
+        {
+            if (activator == null)
+            {
+                return;
+            }
+
+            if (_single is null && _multiple is null)
+            {
+                _single = activator;
+            }
+            else
+            {
+                if (_multiple is null)
+                {
+                    _multiple = new OrQueryActivator(_visual);
+                    _multiple.Add(_single!);
+                    _single = null;
+                }
+
+                _multiple.Add(activator);
+            }
+        }
+
+        public IStyleActivator Get() => _single ?? _multiple!;
+    }
+}
diff --git a/src/Avalonia.Base/Styling/AndQuery.cs b/src/Avalonia.Base/Styling/AndQuery.cs
new file mode 100644
index 0000000000..d57df74c45
--- /dev/null
+++ b/src/Avalonia.Base/Styling/AndQuery.cs
@@ -0,0 +1,100 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using Avalonia.Styling.Activators;
+
+#nullable enable
+
+namespace Avalonia.Styling
+{
+    /// <summary>
+    /// The OR style query.
+    /// </summary>
+    internal sealed class AndQuery : Query
+    {
+        private readonly IReadOnlyList<Query> _queries;
+        private string? _queryString;
+        private Type? _targetType;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="AndQuery"/> class.
+        /// </summary>
+        /// <param name="queries">The queries to AND.</param>
+        public AndQuery(IReadOnlyList<Query> queries)
+        {
+            if (queries is null)
+            {
+                throw new ArgumentNullException(nameof(queries));
+            }
+
+            if (queries.Count <= 1)
+            {
+                throw new ArgumentException("Need more than one query to AND.");
+            }
+
+            _queries = queries;
+        }
+
+        /// <inheritdoc/>
+        internal override bool IsCombinator => false;
+
+        /// <inheritdoc/>
+        public override string ToString(Media? owner)
+        {
+            if (_queryString == null)
+            {
+                _queryString = string.Join(" and ", _queries.Select(x => x.ToString(owner)));
+            }
+
+            return _queryString;
+        }
+
+        internal override SelectorMatch Evaluate(StyledElement control, IStyle? parent, bool subscribe)
+        {
+            if (!(control is Visual visual))
+            {
+                return SelectorMatch.NeverThisType;
+            }
+
+            var activators = new AndQueryActivatorBuilder(visual);
+            var alwaysThisInstance = false;
+
+            var count = _queries.Count;
+
+            for (var i = 0; i < count; i++)
+            {
+                var match = _queries[i].Match(control, parent, subscribe);
+
+                switch (match.Result)
+                {
+                    case SelectorMatchResult.AlwaysThisInstance:
+                        alwaysThisInstance = true;
+                        break;
+                    case SelectorMatchResult.NeverThisInstance:
+                    case SelectorMatchResult.NeverThisType:
+                        return match;
+                    case SelectorMatchResult.Sometimes:
+                        activators.Add(match.Activator!);
+                        break;
+                }
+            }
+
+            if (activators.Count > 0)
+            {
+                return new SelectorMatch(activators.Get());
+            }
+            else if (alwaysThisInstance)
+            {
+                return SelectorMatch.AlwaysThisInstance;
+            }
+            else
+            {
+                return SelectorMatch.AlwaysThisType;
+            }
+        }
+
+        private protected override Query? MovePrevious() => null;
+        private protected override Query? MovePreviousOrParent() => null;
+    }
+}
+
diff --git a/src/Avalonia.Base/Styling/OrQuery.cs b/src/Avalonia.Base/Styling/OrQuery.cs
index 2c1bd65d5c..4f12275831 100644
--- a/src/Avalonia.Base/Styling/OrQuery.cs
+++ b/src/Avalonia.Base/Styling/OrQuery.cs
@@ -51,7 +51,12 @@ namespace Avalonia.Styling
 
         internal override SelectorMatch Evaluate(StyledElement control, IStyle? parent, bool subscribe)
         {
-            var activators = new OrActivatorBuilder();
+            if (!(control is Visual visual))
+            {
+                return SelectorMatch.NeverThisType;
+            }
+
+            var activators = new OrQueryActivatorBuilder(visual);
             var neverThisInstance = false;
 
             var count = _queries.Count;
diff --git a/src/Avalonia.Base/Styling/Queries.cs b/src/Avalonia.Base/Styling/Queries.cs
index 54fada9eed..2e5ae4b522 100644
--- a/src/Avalonia.Base/Styling/Queries.cs
+++ b/src/Avalonia.Base/Styling/Queries.cs
@@ -44,5 +44,25 @@ namespace Avalonia.Styling
         {
             return new OrQuery(query);
         }
+
+        /// <summary>
+        /// Returns a query which ANDs queries.
+        /// </summary>
+        /// <param name="queries">The queries to be AND'd.</param>
+        /// <returns>The query.</returns>
+        public static Query And(params Query[] queries)
+        {
+            return new AndQuery(queries);
+        }
+
+        /// <summary>
+        /// Returns a query which ANDs queries.
+        /// </summary>
+        /// <param name="query">The queries to be AND'd.</param>
+        /// <returns>The query.</returns>
+        public static Query And(IReadOnlyList<Query> query)
+        {
+            return new AndQuery(query);
+        }
     }
 }
diff --git a/src/Markup/Avalonia.Markup.Xaml.Loader/CompilerExtensions/Transformers/AvaloniaXamlIlQueryTransformer.cs b/src/Markup/Avalonia.Markup.Xaml.Loader/CompilerExtensions/Transformers/AvaloniaXamlIlQueryTransformer.cs
index 7b4d2c996a..7f206e894a 100644
--- a/src/Markup/Avalonia.Markup.Xaml.Loader/CompilerExtensions/Transformers/AvaloniaXamlIlQueryTransformer.cs
+++ b/src/Markup/Avalonia.Markup.Xaml.Loader/CompilerExtensions/Transformers/AvaloniaXamlIlQueryTransformer.cs
@@ -44,6 +44,7 @@ namespace Avalonia.Markup.Xaml.XamlIl.CompilerExtensions.Transformers
             {
                 XamlIlQueryNode result = initialNode;
                 XamlIlOrQueryNode results = null;
+                XamlIlAndQueryNode andNode = null;
                 foreach (var i in syntax)
                 {
                     switch (i)
@@ -58,17 +59,31 @@ namespace Avalonia.Markup.Xaml.XamlIl.CompilerExtensions.Transformers
                             result = new XamlIlWidthQuery(result, width);
                             break;
                         case MediaQueryGrammar.HeightSyntax height:
-                            result = new XamlIHeightQuery(result, height);
+                            result = new XamlIlHeightQuery(result, height);
                             break;
-                        case MediaQueryGrammar.CommaSyntax comma:
-                            if (results == null) 
+                        case MediaQueryGrammar.OrSyntax or:
+                            if (results == null)
                                 results = new XamlIlOrQueryNode(node, queryType);
-                            results.Add(result);
+                            if (andNode != null && result == initialNode)
+                                throw new XamlParseException($"Previously opened And node is not closed.", node);
+                            results.Add(andNode ?? result);
+                            result = initialNode;
+                            andNode = null;
+                            break;
+                        case MediaQueryGrammar.AndSyntax and:
+                            if (andNode == null)
+                                andNode = new XamlIlAndQueryNode(node, queryType);
+                            andNode.Add(result);
                             result = initialNode;
                             break;
                         default:
                             throw new XamlParseException($"Unsupported query grammar '{i.GetType()}'.", node);
                     }
+
+                    if (andNode != null && result != initialNode)
+                    {
+                        andNode.Add(result);
+                    }
                 }
 
                 if (results != null && result != null)
@@ -254,11 +269,11 @@ namespace Avalonia.Markup.Xaml.XamlIl.CompilerExtensions.Transformers
         }
     }
     
-    class XamlIHeightQuery : XamlIlQueryNode
+    class XamlIlHeightQuery : XamlIlQueryNode
     {
         private MediaQueryGrammar.HeightSyntax _argument;
         
-        public XamlIHeightQuery(XamlIlQueryNode previous, MediaQueryGrammar.HeightSyntax argument) : base(previous)
+        public XamlIlHeightQuery(XamlIlQueryNode previous, MediaQueryGrammar.HeightSyntax argument) : base(previous)
         {
             _argument = argument;
         }
@@ -359,4 +374,71 @@ namespace Avalonia.Markup.Xaml.XamlIl.CompilerExtensions.Transformers
                 m => m.Name == "Or" && m.Parameters.Count == 1 && m.Parameters[0].Name.StartsWith("IReadOnlyList"));
         }
     }
+
+    class XamlIlAndQueryNode : XamlIlQueryNode
+    {
+        List<XamlIlQueryNode> _queries = new List<XamlIlQueryNode>();
+        public XamlIlAndQueryNode(IXamlLineInfo info, IXamlType queryType) : base(null, info, queryType)
+        {
+        }
+
+        public void Add(XamlIlQueryNode node)
+        {
+            _queries.Add(node);
+        }
+
+        public override IXamlType TargetType
+        {
+            get
+            {
+                IXamlType result = null;
+
+                foreach (var query in _queries)
+                {
+                    if (query.TargetType == null)
+                    {
+                        return null;
+                    }
+                    else if (result == null)
+                    {
+                        result = query.TargetType;
+                    }
+                    else
+                    {
+                        while (!result.IsAssignableFrom(query.TargetType))
+                        {
+                            result = result.BaseType;
+                        }
+                    }
+                }
+
+                return result;
+            }
+        }
+
+        protected override void DoEmit(XamlEmitContext<IXamlILEmitter, XamlILNodeEmitResult> context, IXamlILEmitter codeGen)
+        {
+            if (_queries.Count == 0)
+                throw new XamlLoadException("Invalid query count", this);
+            if (_queries.Count == 1)
+            {
+                _queries[0].Emit(context, codeGen);
+                return;
+            }
+            var listType = context.Configuration.TypeSystem.FindType("System.Collections.Generic.List`1")
+                .MakeGenericType(base.Type.GetClrType());
+            var add = listType.FindMethod("Add", context.Configuration.WellKnownTypes.Void, false, Type.GetClrType());
+            codeGen
+                .Newobj(listType.FindConstructor());
+            foreach (var s in _queries)
+            {
+                codeGen.Dup();
+                context.Emit(s, codeGen, Type.GetClrType());
+                codeGen.EmitCall(add, true);
+            }
+
+            EmitCall(context, codeGen,
+                m => m.Name == "And" && m.Parameters.Count == 1 && m.Parameters[0].Name.StartsWith("IReadOnlyList"));
+        }
+    }
 }
diff --git a/src/Markup/Avalonia.Markup/Markup/Parsers/MediaQueryGrammar.cs b/src/Markup/Avalonia.Markup/Markup/Parsers/MediaQueryGrammar.cs
index 799fcb4d9f..0d7e9881b3 100644
--- a/src/Markup/Avalonia.Markup/Markup/Parsers/MediaQueryGrammar.cs
+++ b/src/Markup/Avalonia.Markup/Markup/Parsers/MediaQueryGrammar.cs
@@ -217,14 +217,25 @@ namespace Avalonia.Markup.Parsers
 
         private static (State, ISyntax?) ParseMiddle(ref CharacterReader r, char? end)
         {
+            r.SkipWhitespace();
+
             if (r.TakeIf(','))
             {
-                return (State.Start, new CommaSyntax());
+                return (State.Start, new OrSyntax());
             }
             else if (end.HasValue && !r.End && r.Peek == end.Value)
             {
                 return (State.End, null);
             }
+            else
+            {
+                var identifier = r.TakeWhile(c => !char.IsWhiteSpace(c));
+
+                if (identifier.SequenceEqual("and".AsSpan()))
+                {
+                    return (State.Start, new AndSyntax());
+                }
+            }
             throw new InvalidOperationException("Invalid syntax found");
         }
         
@@ -284,11 +295,19 @@ namespace Avalonia.Markup.Parsers
             }
         }
 
-        public class CommaSyntax : ISyntax
+        public class OrSyntax : ISyntax
+        {
+            public override bool Equals(object? obj)
+            {
+                return obj is OrSyntax;
+            }
+        }
+
+        public class AndSyntax : ISyntax
         {
             public override bool Equals(object? obj)
             {
-                return obj is CommaSyntax;
+                return obj is AndSyntax;
             }
         }
 
diff --git a/src/Markup/Avalonia.Markup/Markup/Parsers/MediaQueryParser.cs b/src/Markup/Avalonia.Markup/Markup/Parsers/MediaQueryParser.cs
index 9059fbb6a5..131136d771 100644
--- a/src/Markup/Avalonia.Markup/Markup/Parsers/MediaQueryParser.cs
+++ b/src/Markup/Avalonia.Markup/Markup/Parsers/MediaQueryParser.cs
@@ -13,19 +13,11 @@ namespace Avalonia.Markup.Parsers
     /// </summary>
     internal class MediaQueryParser
     {
-        private readonly Func<string, string, Type> _typeResolver;
-
         /// <summary>
         /// Initializes a new instance of the <see cref="MediaQueryParser"/> class.
         /// </summary>
-        /// <param name="typeResolver">
-        /// The type resolver to use. The type resolver is a function which accepts two strings:
-        /// a type name and a XML namespace prefix and a type name, and should return the resolved
-        /// type or throw an exception.
-        /// </param>
-        public MediaQueryParser(Func<string, string, Type> typeResolver)
+        public MediaQueryParser()
         {
-            _typeResolver = typeResolver;
         }
 
         /// <summary>
@@ -51,16 +43,26 @@ namespace Avalonia.Markup.Parsers
                 switch (i)
                 {
                     case MediaQueryGrammar.OrientationSyntax orientation:
-                        result = Queries.Orientation(result, orientation.Argument);
+                        result = result.Orientation(orientation.Argument);
                         break;
                     case MediaQueryGrammar.WidthSyntax width:
-                        result = Queries.Width(result, width.LeftOperator, width.Left, width.RightOperator, width.Right);
+                        result = result.Width(width.LeftOperator, width.Left, width.RightOperator, width.Right);
                         break;
                     case MediaQueryGrammar.HeightSyntax height:
-                        result = Queries.Height(result, height.LeftOperator, height.Left, height.RightOperator, height.Right);
+                        result = result.Height(height.LeftOperator, height.Left, height.RightOperator, height.Right);
                         break;
                     case MediaQueryGrammar.PlatformSyntax platform:
-                        result = Queries.Platform(result, platform.Argument);
+                        result = result.Platform(platform.Argument);
+                        break;
+                    case MediaQueryGrammar.OrSyntax or:
+                    case MediaQueryGrammar.AndSyntax and:
+                        if (results == null)
+                        {
+                            results = new List<Query>();
+                        }
+
+                        results.Add(result ?? throw new NotSupportedException("Invalid query!"));
+                        result = null;
                         break;
                     default:
                         throw new NotSupportedException($"Unsupported selector grammar '{i.GetType()}'.");
@@ -79,18 +81,5 @@ namespace Avalonia.Markup.Parsers
 
             return result;
         }
-
-        private Type Resolve(string xmlns, string typeName)
-        {
-            var result = _typeResolver(xmlns, typeName);
-
-            if (result == null)
-            {
-                var type = string.IsNullOrWhiteSpace(xmlns) ? typeName : xmlns + ':' + typeName;
-                throw new InvalidOperationException($"Could not resolve type '{type}'");
-            }
-
-            return result;
-        }
     }
 }
diff --git a/tests/Avalonia.Markup.UnitTests/Parsers/QueryGrammarTests.cs b/tests/Avalonia.Markup.UnitTests/Parsers/QueryGrammarTests.cs
new file mode 100644
index 0000000000..be804824e0
--- /dev/null
+++ b/tests/Avalonia.Markup.UnitTests/Parsers/QueryGrammarTests.cs
@@ -0,0 +1,104 @@
+using System.Linq;
+using Avalonia.Data.Core;
+using Avalonia.Markup.Parsers;
+using Xunit;
+
+namespace Avalonia.Markup.UnitTests.Parsers
+{
+    public class QueryGrammarTests
+    {
+        [Fact]
+        public void Width()
+        {
+            var result = MediaQueryGrammar.Parse("width >= 100");
+
+            Assert.Equal(
+                new[] { new MediaQueryGrammar.WidthSyntax()
+                {
+                    Right = 100,
+                    RightOperator = Styling.QueryComparisonOperator.GreaterThanOrEquals
+                }, },
+                result);
+
+            result = MediaQueryGrammar.Parse("100 <= width");
+
+            Assert.Equal(
+                new[] { new MediaQueryGrammar.WidthSyntax()
+                {
+                    Left = 100,
+                    LeftOperator = Styling.QueryComparisonOperator.GreaterThanOrEquals
+                }, },
+                result);
+
+            result = MediaQueryGrammar.Parse("100 <= width < 200");
+
+            Assert.Equal(
+                new[] { new MediaQueryGrammar.WidthSyntax()
+                {
+                    Left = 100,
+                    LeftOperator = Styling.QueryComparisonOperator.GreaterThanOrEquals,
+                    Right = 200,
+                    RightOperator = Styling.QueryComparisonOperator.LessThan
+                }, },
+                result);
+        }
+
+        [Fact]
+        public void Height()
+        {
+            var result = MediaQueryGrammar.Parse("height >= 100");
+
+            Assert.Equal(
+                new[] { new MediaQueryGrammar.HeightSyntax()
+                {
+                    Right = 100,
+                    RightOperator = Styling.QueryComparisonOperator.GreaterThanOrEquals
+                }, },
+                result);
+
+            result = MediaQueryGrammar.Parse("100 <= height");
+
+            Assert.Equal(
+                new[] { new MediaQueryGrammar.HeightSyntax()
+                {
+                    Left = 100,
+                    LeftOperator = Styling.QueryComparisonOperator.GreaterThanOrEquals
+                }, },
+                result);
+
+            result = MediaQueryGrammar.Parse("100 <= height < 200");
+
+            Assert.Equal(
+                new[] { new MediaQueryGrammar.HeightSyntax()
+                {
+                    Left = 100,
+                    LeftOperator = Styling.QueryComparisonOperator.GreaterThanOrEquals,
+                    Right = 200,
+                    RightOperator = Styling.QueryComparisonOperator.LessThan
+                }, },
+                result);
+        }
+
+        [Fact]
+        public void Orientation()
+        {
+            var result = MediaQueryGrammar.Parse("orientation:portrait");
+
+            Assert.Equal(
+                new[] { new MediaQueryGrammar.OrientationSyntax()
+                {
+                    Argument = Styling.MediaOrientation.Portrait
+                }, },
+                result);
+
+            result = MediaQueryGrammar.Parse("orientation:landscape");
+
+            Assert.Equal(
+                new[] { new MediaQueryGrammar.OrientationSyntax()
+                {
+                    Argument = Styling.MediaOrientation.Landscape
+                }, },
+                result);
+        }
+    }
+}
diff --git a/tests/Avalonia.Markup.UnitTests/Parsers/QueryParserTests.cs b/tests/Avalonia.Markup.UnitTests/Parsers/QueryParserTests.cs
new file mode 100644
index 0000000000..f0dcdef097
--- /dev/null
+++ b/tests/Avalonia.Markup.UnitTests/Parsers/QueryParserTests.cs
@@ -0,0 +1,24 @@
+using System;
+using Avalonia.Controls;
+using Avalonia.Markup.Parsers;
+using Xunit;
+
+namespace Avalonia.Markup.UnitTests.Parsers
+{
+    public class QueryParserTests
+    {
+        [Fact]
+        public void Parses_Or_Queries()
+        {
+            var target = new MediaQueryParser();
+            var result = target.Parse("orientation:portrait , width > 0");
+        }
+
+        [Fact]
+        public void Parses_And_Queries()
+        {
+            var target = new MediaQueryParser();
+            var result = target.Parse("orientation:portrait and width > 0");
+        }
+    }
+}