Merge pull request #11304 from AvaloniaUI/fixes/animation-expression-parsing

Fix TokenParser

src/Avalonia.Base/Rendering/Composition/Expressions/TokenParser.cs

@@ -243,7 +243,7 @@ namespace Avalonia.Rendering.Composition.Expressions
                 else if (ch == '-')
                 {
                     if (len != 0)
-                        return false;
+                        break;
                     len = c + 1;
                 }
                 else

tests/Avalonia.Base.UnitTests/Composition/CompositionAnimationParserTests.cs

@@ -0,0 +1,39 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Reflection;
+using Avalonia.Animation.Easings;
+using Avalonia.Base.UnitTests.Rendering;
+using Avalonia.Rendering;
+using Avalonia.Rendering.Composition;
+using Avalonia.Rendering.Composition.Expressions;
+using Avalonia.Rendering.Composition.Server;
+using Avalonia.Threading;
+using Avalonia.UnitTests;
+using Xunit;
+using Xunit.Sdk;
+
+namespace Avalonia.Base.UnitTests.Composition;
+
+public class CompositionAnimationParserTests
+{
+    [Theory,
+     InlineData("Vector3(0.5+(4.0-0.5)* -2, 1, 0).X", -6.5)]
+    public void EvaluatesExpressionCorrectly(string expression, double value)
+    {
+        var expr = ExpressionParser.Parse(expression);
+        var ctx = new ExpressionEvaluationContext
+        {
+            ForeignFunctionInterface = BuiltInExpressionFfi.Instance,
+        };
+        var res = expr.Evaluate(ref ctx);
+        double doubleRes;
+        if (res.Type == VariantType.Scalar)
+            doubleRes = res.Scalar;
+        else if (res.Type == VariantType.Double)
+            doubleRes = res.Double;
+        else
+            throw new Exception("Invalid result type: " + res.Type);
+        Assert.Equal(value, doubleRes);
+    }
+}