Migrate to PEG parser. Introduce boolean operators and constants.

samples/CommunityToolkit.Maui.Sample/Pages/Converters/MultiMathExpressionConverterPage.xaml

@@ -15,63 +15,86 @@
         </ResourceDictionary>
     </pages:BasePage.Resources>
 
-    <Grid Padding="20"
-          RowSpacing="20"
-          ColumnSpacing="12"
-          ColumnDefinitions="*,*,*,*,*,*,*"
-          RowDefinitions="100, *">
-        <Label Grid.ColumnSpan="7"
-               Grid.Row="0"
-               Text="This sample demonstrates the use of the MultiMathExpressionConverter. It utilizes the converter to perform various math operations of multiple variables."/>
+    <VerticalStackLayout Padding="20" Spacing="40">
 
-        <Entry Grid.Column="0"
-               Grid.Row="1"
-               VerticalTextAlignment="Center"
-               VerticalOptions="Center"
-               Text="{Binding X0}"/>
+        <Grid RowSpacing="20"
+              ColumnSpacing="12"
+              ColumnDefinitions="*,*,*,*,*,*,*"
+              RowDefinitions="100, *">
+            <Label Grid.ColumnSpan="7"
+                   Grid.Row="0"
+                   Text="This sample demonstrates the use of the MultiMathExpressionConverter. It utilizes the converter to perform various math operations of multiple variables."/>
 
-        <Label Grid.Column="1"
-               Grid.Row="1"
-               VerticalTextAlignment="Center"
-               VerticalOptions="Center"
-               Text="+" />
+            <Entry Grid.Column="0"
+                   Grid.Row="1"
+                   VerticalTextAlignment="Center"
+                   VerticalOptions="Center"
+                   Text="{Binding X0}"/>
 
-        <Entry Grid.Column="2"
-               Grid.Row="1"
-               VerticalTextAlignment="Center"
-               VerticalOptions="Center"
-               Text="{Binding X1}"/>
+            <Label Grid.Column="1"
+                   Grid.Row="1"
+                   VerticalTextAlignment="Center"
+                   VerticalOptions="Center"
+                   Text="+" />
 
-        <Label Grid.Column="3"
-               Grid.Row="1"
-               VerticalTextAlignment="Center"
-               VerticalOptions="Center"
-               Text="+" />
+            <Entry Grid.Column="2"
+                   Grid.Row="1"
+                   VerticalTextAlignment="Center"
+                   VerticalOptions="Center"
+                   Text="{Binding X1}"/>
 
-        <Entry Grid.Column="4"
-               Grid.Row="1"
-               VerticalTextAlignment="Center"
-               VerticalOptions="Center"
-               Text="{Binding X2}"/>
+            <Label Grid.Column="3"
+                   Grid.Row="1"
+                   VerticalTextAlignment="Center"
+                   VerticalOptions="Center"
+                   Text="+" />
 
-        <Label Grid.Column="5"
-               Grid.Row="1"
-               VerticalTextAlignment="Center"
-               VerticalOptions="Center"
-               Text="=" />
+            <Entry Grid.Column="4"
+                   Grid.Row="1"
+                   VerticalTextAlignment="Center"
+                   VerticalOptions="Center"
+                   Text="{Binding X2}"/>
 
-        <Label Grid.Column="6"
-               Grid.Row="1"
-               VerticalTextAlignment="Center"
-               VerticalOptions="Center">
-             <Label.Text>
-                <MultiBinding Converter="{StaticResource MultiMathExpressionConverter}"
-                              ConverterParameter="x0 + x1 + x2">
-                    <Binding Path="X0" Mode="OneWay"/>
-                    <Binding Path="X1" Mode="OneWay"/>
-                    <Binding Path="X2" Mode="OneWay"/>
-                </MultiBinding>
-            </Label.Text>           
+            <Label Grid.Column="5"
+                   Grid.Row="1"
+                   VerticalTextAlignment="Center"
+                   VerticalOptions="Center"
+                   Text="=" />
+
+            <Label Grid.Column="6"
+                   Grid.Row="1"
+                   VerticalTextAlignment="Center"
+                   VerticalOptions="Center">
+                 <Label.Text>
+                    <MultiBinding Converter="{StaticResource MultiMathExpressionConverter}"
+                                  ConverterParameter="x0 + x1 + x2">
+                        <Binding Path="X0" Mode="OneWay"/>
+                        <Binding Path="X1" Mode="OneWay"/>
+                        <Binding Path="X2" Mode="OneWay"/>
+                    </MultiBinding>
+                </Label.Text>           
+            </Label>
+        </Grid>
+
+        <Label HorizontalOptions="Center"
+               Text="Valid: Value greater than or equal to 60"
+               TextColor="Green">
+            <Label.Triggers>
+                <DataTrigger TargetType="Label" Value="False">
+                    <DataTrigger.Binding>
+                        <MultiBinding Converter="{StaticResource MultiMathExpressionConverter}"
+                                      ConverterParameter="x0 + x1 + x2 &gt;= 60">
+                            <Binding Path="X0" Mode="OneWay"/>
+                            <Binding Path="X1" Mode="OneWay"/>
+                            <Binding Path="X2" Mode="OneWay"/>
+                       </MultiBinding>
+                    </DataTrigger.Binding>
+                    <Setter Property="Text" Value="Error: Value not greater than or equal to 60"/>
+                    <Setter Property="TextColor" Value="Red"/>
+                </DataTrigger>
+            </Label.Triggers>
         </Label>
-    </Grid>
+
+    </VerticalStackLayout>
+
 </pages:BasePage>

src/CommunityToolkit.Maui.Core/Primitives/MathOperator.shared.cs

@@ -27,17 +27,14 @@ public sealed class MathOperator
 	/// </summary>
 	/// <param name="name">Name</param>
 	/// <param name="numericCount">Number of Numerals</param>
-	/// <param name="precedence">Math Operator Preference</param>
 	/// <param name="calculateFunc">Calculation Function</param>
 	public MathOperator(
 		string name,
 		int numericCount,
-		MathOperatorPrecedence precedence,
-		Func<double[], double> calculateFunc)
+		Func<object?[], object?> calculateFunc)
 	{
 		Name = name;
 		CalculateFunc = calculateFunc;
-		Precedence = precedence;
 		NumericCount = numericCount;
 	}
 
@@ -59,5 +56,5 @@ public MathOperator(
 	/// <summary>
 	/// Calculation Function
 	/// </summary>
-	public Func<double[], double> CalculateFunc { get; }
+	public Func<object?[], object?> CalculateFunc { get; }
 }

src/CommunityToolkit.Maui.UnitTests/Converters/MathExpressionConverterTests.cs

@@ -29,16 +29,41 @@ public void MathExpressionConverter_ReturnsCorrectResult(string expression, doub
 		var convertResult = ((ICommunityToolkitValueConverter)mathExpressionConverter).Convert(x, mathExpressionTargetType, expression, cultureInfo) ?? throw new NullReferenceException();
 		var convertFromResult = mathExpressionConverter.ConvertFrom(x, expression);
 
+		Assert.True(convertFromResult is not null);
 		Assert.True(Math.Abs((double)convertResult - expectedResult) < tolerance);
-		Assert.True(Math.Abs(convertFromResult - expectedResult) < tolerance);
+		Assert.True(Math.Abs((double)convertFromResult - expectedResult) < tolerance);
+	}
+
+	[Theory]
+	[InlineData("3 < x", 2d, false)]
+	[InlineData("x > 3", 2d, false)]
+	[InlineData("3 < x == x > 3", 2d, true)]
+	[InlineData("3 <= x != 3 >= x", 2d, true)]
+	[InlineData("x >= 1", 2d, true)]
+	[InlineData("x <= 3", 2d, true)]
+	[InlineData("x >= 1 && (x <= 3 || x >= 0)", 2d, true)]
+	[InlineData("true", 2d, true)]
+	[InlineData("false", 2d, false)]
+	[InlineData("-x > 2", 3d, false)]
+	[InlineData("!!! (---x > 2)", 3d, true)]
+	public void MathExpressionConverter_WithComparisonOperator_ReturnsCorrectBooleanResult(string expression, double x, bool expectedResult)
+	{
+		var mathExpressionConverter = new MathExpressionConverter();
+
+		var convertResult = ((ICommunityToolkitValueConverter)mathExpressionConverter).Convert(x, mathExpressionTargetType, expression, cultureInfo) ?? throw new NullReferenceException();
+		var convertFromResult = mathExpressionConverter.ConvertFrom(x, expression);
+
+		Assert.True(convertFromResult is not null);
+		Assert.True((bool)convertResult == expectedResult);
+		Assert.True((bool)convertFromResult == expectedResult);
 	}
 
 	[Theory]
 	[InlineData("x + x1 * x1", new object[] { 2d, 1d }, 3d)]
 	[InlineData("(x1 + x) * x1", new object[] { 2d, 3d }, 15d)]
 	[InlineData("3 + x * x1 / (1 - 5)^x1", new object[] { 4d, 2d }, 3.5d)]
 	[InlineData("3 + 4 * 2 + cos(100 + x) / (x1 - 5)^2 + pow(x0, 2)", new object[] { 20d, 1d }, 411.05088631065792d)]
-	public void MathExpressionConverter_WithMultiplyVariable_ReturnsCorrectResult(string expression, object[] variables, double expectedResult)
+	public void MathExpressionConverter_WithMultipleVariable_ReturnsCorrectResult(string expression, object[] variables, double expectedResult)
 	{
 		var mathExpressionConverter = new MultiMathExpressionConverter();
 
@@ -47,16 +72,74 @@ public void MathExpressionConverter_WithMultiplyVariable_ReturnsCorrectResult(st
 		Assert.True(Math.Abs((double)result - expectedResult) < tolerance);
 	}
 
+	[Theory]
+	[InlineData("x == 3 && x1", new object?[] { 3d, 4d }, 4d)]
+	[InlineData("x != 3 || x1", new object?[] { 3d, 4d }, 4d)]
+	[InlineData("x + x1 || true", new object?[] { 3d, 4d }, 7d)]
+	[InlineData("x + x1 && false", new object?[] { 2d, -2d }, 0d)]
+	public void MathExpressionConverter_WithBooleanOperator_ReturnsCorrectNumberResult(string expression, object[] variables, double expectedResult)
+	{
+		var mathExpressionConverter = new MultiMathExpressionConverter();
+
+		object? result = mathExpressionConverter.Convert(variables, mathExpressionTargetType, expression);
+
+		Assert.True(result is not null);
+		Assert.Equal(expectedResult, result);
+	}
+
+	[Theory]
+	[InlineData("x != 3 && x1", new object?[] { 3d, 4d }, false)]
+	[InlineData("x == 3 || x1", new object?[] { 3d, 4d }, true)]
+	public void MathExpressionConverter_WithBooleanOperator_ReturnsCorrectBooleanResult(string expression, object[] variables, bool expectedResult)
+	{
+		var mathExpressionConverter = new MultiMathExpressionConverter();
+
+		object? result = mathExpressionConverter.Convert(variables, mathExpressionTargetType, expression);
+
+		Assert.True(result is not null);
+		Assert.Equal(expectedResult, result);
+	}
+
+	[Theory]
+	[InlineData("x == 3 && x1", new object?[] { 3d, null})]
+	[InlineData("x != 3 || x1", new object?[] { 3d, null })]
+	[InlineData("x == 3 ? x1 : x2", new object?[] { 3d, null, 5d })]
+	[InlineData("x != 3 ? x1 : x2", new object?[] { 3d, 4d, null})]
+	public void MathExpressionConverter_ReturnsCorrectNullResult(string expression, object[] variables)
+	{
+		var mathExpressionConverter = new MultiMathExpressionConverter();
+
+		object? result = mathExpressionConverter.Convert(variables, mathExpressionTargetType, expression);
+
+		Assert.True(result is null);
+	}
+
+	[Theory]
+	[InlineData("x == x1", new object?[] { 2d, 2d }, true)]
+	[InlineData("x == x1", new object?[] { 2d, null }, false)]
+	[InlineData("x == x1", new object?[] { null, 2d}, false)]
+	[InlineData("x == x1", new object?[] { null, null }, true)]
+	[InlineData("(x ? x1 : x2) == null", new object?[] { true, null, 2d }, true)]
+	public void MathExpressionConverter_WithEqualityOperator_ReturnsCorrectBooleanResult(string expression, object[] variables, bool expectedResult)
+	{
+		var mathExpressionConverter = new MultiMathExpressionConverter();
+
+		object? result = mathExpressionConverter.Convert(variables, mathExpressionTargetType, expression);
+
+		Assert.True(result is not null);
+		Assert.Equal(expectedResult, result);
+	}
+
 	[Theory]
 	[InlineData("1 + 3 + 5 + (3 - 2))")]
 	[InlineData("1 + 2) + (9")]
 	[InlineData("100 + pow(2)")]
-	public void MathExpressionConverterThrowsArgumentException(string expression)
+	public void MathExpressionConverter_WithInvalidExpressions_ReturnsNullResult(string expression)
 	{
 		var mathExpressionConverter = new MathExpressionConverter();
 
-		Assert.Throws<ArgumentException>(() => ((ICommunityToolkitValueConverter)mathExpressionConverter).Convert(0d, mathExpressionTargetType, expression, cultureInfo));
-		Assert.Throws<ArgumentException>(() => mathExpressionConverter.ConvertFrom(0d, expression));
+		Assert.Null(((ICommunityToolkitValueConverter)mathExpressionConverter).Convert(0d, mathExpressionTargetType, expression, cultureInfo));
+		Assert.Null(mathExpressionConverter.ConvertFrom(0d, expression));
 	}
 
 	[Theory]
@@ -74,7 +157,7 @@ public void MultiMathExpressionConverterInvalidParameterThrowsArgumentException(
 	public void MultiMathExpressionConverterInvalidValuesReturnsNull()
 	{
 		var mathExpressionConverter = new MultiMathExpressionConverter();
-		var result = mathExpressionConverter.Convert([0d, null], mathExpressionTargetType, "x", cultureInfo);
+		var result = mathExpressionConverter.Convert([0d, null], mathExpressionTargetType, "x + x1", cultureInfo);
 		result.Should().BeNull();
 	}
 
@@ -85,9 +168,9 @@ public void MathExpressionConverterNullInputTest()
 		Assert.Throws<ArgumentNullException>(() => ((ICommunityToolkitValueConverter)new MathExpressionConverter()).Convert(0.0, null, "x", null));
 		Assert.Throws<ArgumentNullException>(() => ((ICommunityToolkitValueConverter)new MathExpressionConverter()).ConvertBack(0.0, null, null, null));
 #pragma warning restore CS8625 // Cannot convert null literal to non-nullable reference type.
-		Assert.Throws<ArgumentNullException>(() => ((ICommunityToolkitValueConverter)new MathExpressionConverter()).Convert(null, typeof(bool), "x", null));
+		Assert.True(((ICommunityToolkitValueConverter)new MathExpressionConverter()).Convert(null, typeof(bool), "x", null) is null);
 		Assert.Throws<ArgumentNullException>(() => ((ICommunityToolkitValueConverter)new MathExpressionConverter()).Convert(null, typeof(bool), null, null));
-		Assert.Throws<ArgumentNullException>(() => ((ICommunityToolkitValueConverter)new MathExpressionConverter()).ConvertBack(null, typeof(bool), null, null));
+		Assert.Throws<NotSupportedException>(() => ((ICommunityToolkitValueConverter)new MathExpressionConverter()).ConvertBack(null, typeof(bool), null, null));
 	}
 
 	[Fact]