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ADD: Conditional interpolated string handlers
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‎CHANGELOG.md‎

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@@ -9,6 +9,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
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### New features
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- Structs `Louis.Text.TrueConditionInterpolatedStringHandler` and `Louis.Text.FalseConditionInterpolatedStringHandler` are interpolated string handlers that only perform formatting if a given condition is true or false, respectively.
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They can help implement, for example, conditional logging methods that take a condition and an interpolated string as a parameter, ensuring that string interpolation will only be performed if the result is actually used.
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### Changes to existing features
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### Bugs fixed in this release

‎src/Louis/PublicAPI/net6.0/PublicAPI.Unshipped.txt‎

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#nullable enable
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Louis.Text.FalseConditionInterpolatedStringHandler
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Louis.Text.FalseConditionInterpolatedStringHandler.AppendFormatted(object? value, int alignment = 0, string? format = null) -> void
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Louis.Text.FalseConditionInterpolatedStringHandler.AppendFormatted(string? value) -> void
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Louis.Text.FalseConditionInterpolatedStringHandler.AppendFormatted(string? value, int alignment = 0, string? format = null) -> void
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Louis.Text.FalseConditionInterpolatedStringHandler.AppendFormatted(System.ReadOnlySpan<char> value) -> void
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Louis.Text.FalseConditionInterpolatedStringHandler.AppendFormatted(System.ReadOnlySpan<char> value, int alignment = 0, string? format = null) -> void
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Louis.Text.FalseConditionInterpolatedStringHandler.AppendFormatted<T>(T value) -> void
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Louis.Text.FalseConditionInterpolatedStringHandler.AppendFormatted<T>(T value, int alignment) -> void
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Louis.Text.FalseConditionInterpolatedStringHandler.AppendFormatted<T>(T value, int alignment, string? format) -> void
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Louis.Text.FalseConditionInterpolatedStringHandler.AppendFormatted<T>(T value, string? format) -> void
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Louis.Text.FalseConditionInterpolatedStringHandler.AppendLiteral(string! value) -> void
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Louis.Text.FalseConditionInterpolatedStringHandler.FalseConditionInterpolatedStringHandler() -> void
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Louis.Text.FalseConditionInterpolatedStringHandler.FalseConditionInterpolatedStringHandler(int literalLength, int formattedCount, bool condition, out bool shouldAppend) -> void
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Louis.Text.FalseConditionInterpolatedStringHandler.ToStringAndClear() -> string!
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Louis.Text.TrueConditionInterpolatedStringHandler
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Louis.Text.TrueConditionInterpolatedStringHandler.AppendFormatted(object? value, int alignment = 0, string? format = null) -> void
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Louis.Text.TrueConditionInterpolatedStringHandler.AppendFormatted(string? value) -> void
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Louis.Text.TrueConditionInterpolatedStringHandler.AppendFormatted(string? value, int alignment = 0, string? format = null) -> void
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Louis.Text.TrueConditionInterpolatedStringHandler.AppendFormatted(System.ReadOnlySpan<char> value) -> void
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Louis.Text.TrueConditionInterpolatedStringHandler.AppendFormatted(System.ReadOnlySpan<char> value, int alignment = 0, string? format = null) -> void
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Louis.Text.TrueConditionInterpolatedStringHandler.AppendFormatted<T>(T value) -> void
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Louis.Text.TrueConditionInterpolatedStringHandler.AppendFormatted<T>(T value, int alignment) -> void
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Louis.Text.TrueConditionInterpolatedStringHandler.AppendFormatted<T>(T value, int alignment, string? format) -> void
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Louis.Text.TrueConditionInterpolatedStringHandler.AppendFormatted<T>(T value, string? format) -> void
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Louis.Text.TrueConditionInterpolatedStringHandler.AppendLiteral(string! value) -> void
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Louis.Text.TrueConditionInterpolatedStringHandler.ToStringAndClear() -> string!
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Louis.Text.TrueConditionInterpolatedStringHandler.TrueConditionInterpolatedStringHandler() -> void
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Louis.Text.TrueConditionInterpolatedStringHandler.TrueConditionInterpolatedStringHandler(int literalLength, int formattedCount, bool condition, out bool shouldAppend) -> void

‎src/Louis/PublicAPI/net7.0/PublicAPI.Unshipped.txt‎

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#nullable enable
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Louis.Text.FalseConditionInterpolatedStringHandler
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Louis.Text.FalseConditionInterpolatedStringHandler.AppendFormatted(object? value, int alignment = 0, string? format = null) -> void
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Louis.Text.FalseConditionInterpolatedStringHandler.AppendFormatted(string? value) -> void
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Louis.Text.FalseConditionInterpolatedStringHandler.AppendFormatted(string? value, int alignment = 0, string? format = null) -> void
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Louis.Text.FalseConditionInterpolatedStringHandler.AppendFormatted(System.ReadOnlySpan<char> value) -> void
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Louis.Text.FalseConditionInterpolatedStringHandler.AppendFormatted(System.ReadOnlySpan<char> value, int alignment = 0, string? format = null) -> void
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Louis.Text.FalseConditionInterpolatedStringHandler.AppendFormatted<T>(T value) -> void
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Louis.Text.FalseConditionInterpolatedStringHandler.AppendFormatted<T>(T value, int alignment) -> void
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Louis.Text.FalseConditionInterpolatedStringHandler.AppendFormatted<T>(T value, int alignment, string? format) -> void
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Louis.Text.FalseConditionInterpolatedStringHandler.AppendFormatted<T>(T value, string? format) -> void
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Louis.Text.FalseConditionInterpolatedStringHandler.AppendLiteral(string! value) -> void
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Louis.Text.FalseConditionInterpolatedStringHandler.FalseConditionInterpolatedStringHandler() -> void
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Louis.Text.FalseConditionInterpolatedStringHandler.FalseConditionInterpolatedStringHandler(int literalLength, int formattedCount, bool condition, out bool shouldAppend) -> void
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Louis.Text.FalseConditionInterpolatedStringHandler.ToStringAndClear() -> string!
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Louis.Text.TrueConditionInterpolatedStringHandler
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Louis.Text.TrueConditionInterpolatedStringHandler.AppendFormatted(object? value, int alignment = 0, string? format = null) -> void
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Louis.Text.TrueConditionInterpolatedStringHandler.AppendFormatted(string? value) -> void
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Louis.Text.TrueConditionInterpolatedStringHandler.AppendFormatted(string? value, int alignment = 0, string? format = null) -> void
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Louis.Text.TrueConditionInterpolatedStringHandler.AppendFormatted(System.ReadOnlySpan<char> value) -> void
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Louis.Text.TrueConditionInterpolatedStringHandler.AppendFormatted(System.ReadOnlySpan<char> value, int alignment = 0, string? format = null) -> void
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Louis.Text.TrueConditionInterpolatedStringHandler.AppendFormatted<T>(T value) -> void
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Louis.Text.TrueConditionInterpolatedStringHandler.AppendFormatted<T>(T value, int alignment) -> void
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Louis.Text.TrueConditionInterpolatedStringHandler.AppendFormatted<T>(T value, int alignment, string? format) -> void
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Louis.Text.TrueConditionInterpolatedStringHandler.AppendFormatted<T>(T value, string? format) -> void
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Louis.Text.TrueConditionInterpolatedStringHandler.AppendLiteral(string! value) -> void
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Louis.Text.TrueConditionInterpolatedStringHandler.ToStringAndClear() -> string!
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Louis.Text.TrueConditionInterpolatedStringHandler.TrueConditionInterpolatedStringHandler() -> void
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Louis.Text.TrueConditionInterpolatedStringHandler.TrueConditionInterpolatedStringHandler(int literalLength, int formattedCount, bool condition, out bool shouldAppend) -> void

‎src/Louis/PublicAPI/net8.0/PublicAPI.Unshipped.txt‎

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#nullable enable
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Louis.Text.FalseConditionInterpolatedStringHandler
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Louis.Text.FalseConditionInterpolatedStringHandler.AppendFormatted(object? value, int alignment = 0, string? format = null) -> void
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Louis.Text.FalseConditionInterpolatedStringHandler.AppendFormatted(string? value) -> void
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Louis.Text.FalseConditionInterpolatedStringHandler.AppendFormatted(string? value, int alignment = 0, string? format = null) -> void
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Louis.Text.FalseConditionInterpolatedStringHandler.AppendFormatted(System.ReadOnlySpan<char> value) -> void
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Louis.Text.FalseConditionInterpolatedStringHandler.AppendFormatted(System.ReadOnlySpan<char> value, int alignment = 0, string? format = null) -> void
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Louis.Text.FalseConditionInterpolatedStringHandler.AppendFormatted<T>(T value) -> void
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Louis.Text.FalseConditionInterpolatedStringHandler.AppendFormatted<T>(T value, int alignment) -> void
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Louis.Text.FalseConditionInterpolatedStringHandler.AppendFormatted<T>(T value, int alignment, string? format) -> void
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Louis.Text.FalseConditionInterpolatedStringHandler.AppendFormatted<T>(T value, string? format) -> void
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Louis.Text.FalseConditionInterpolatedStringHandler.AppendLiteral(string! value) -> void
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Louis.Text.FalseConditionInterpolatedStringHandler.FalseConditionInterpolatedStringHandler() -> void
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Louis.Text.FalseConditionInterpolatedStringHandler.FalseConditionInterpolatedStringHandler(int literalLength, int formattedCount, bool condition, out bool shouldAppend) -> void
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Louis.Text.FalseConditionInterpolatedStringHandler.ToStringAndClear() -> string!
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Louis.Text.TrueConditionInterpolatedStringHandler
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Louis.Text.TrueConditionInterpolatedStringHandler.AppendFormatted(object? value, int alignment = 0, string? format = null) -> void
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Louis.Text.TrueConditionInterpolatedStringHandler.AppendFormatted(string? value) -> void
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Louis.Text.TrueConditionInterpolatedStringHandler.AppendFormatted(string? value, int alignment = 0, string? format = null) -> void
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Louis.Text.TrueConditionInterpolatedStringHandler.AppendFormatted(System.ReadOnlySpan<char> value) -> void
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Louis.Text.TrueConditionInterpolatedStringHandler.AppendFormatted(System.ReadOnlySpan<char> value, int alignment = 0, string? format = null) -> void
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Louis.Text.TrueConditionInterpolatedStringHandler.AppendFormatted<T>(T value) -> void
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Louis.Text.TrueConditionInterpolatedStringHandler.AppendFormatted<T>(T value, int alignment) -> void
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Louis.Text.TrueConditionInterpolatedStringHandler.AppendFormatted<T>(T value, int alignment, string? format) -> void
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Louis.Text.TrueConditionInterpolatedStringHandler.AppendFormatted<T>(T value, string? format) -> void
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Louis.Text.TrueConditionInterpolatedStringHandler.AppendLiteral(string! value) -> void
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Louis.Text.TrueConditionInterpolatedStringHandler.ToStringAndClear() -> string!
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Louis.Text.TrueConditionInterpolatedStringHandler.TrueConditionInterpolatedStringHandler() -> void
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Louis.Text.TrueConditionInterpolatedStringHandler.TrueConditionInterpolatedStringHandler(int literalLength, int formattedCount, bool condition, out bool shouldAppend) -> void

‎src/Louis/Text/FalseConditionInterpolatedStringHandler.cs‎

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// Copyright (c) Tenacom and contributors. Licensed under the MIT license.
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// See the LICENSE file in the project root for full license information.
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#if NET6_0_OR_GREATER
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using System;
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using System.Runtime.CompilerServices;
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using System.Text;
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namespace Louis.Text;
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#pragma warning disable CA1815 // Override equals and operator equals on value types - They would never be used anyway
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#pragma warning disable RS0027 // API with optional parameter(s) should have the most parameters amongst its public overloads - Just mimicking StringBuilder.AppendInterpolatedStringHandler's APIs here.
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/// <summary>
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/// <para>Provides an interpolated string handler that only performs formatting if a given condition is <see langword="false"/>.</para>
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/// <para>This type is only available on .NET 6.0 and greater.</para>
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/// <para>This type is only meant to be used by compiler-generated code. As such, it performs no parameter validation whatsoever.</para>
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/// <example>
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/// <para>The following code shows how this type can be used as an interpolated string handler:</para>
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/// <code>
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/// using System;
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/// using System.Runtime.CompilerServices;
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///
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/// public static class ConsoleUtility
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/// {
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/// // Write a message to the console only if condition is false.
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/// // Usage example: ConsoleUtility.WriteLineUnless(myVar > 0, $"{nameof(myVar)} is {myVar} but should be greater than zero.");
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/// // String interpolation will only take place if necessary.
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/// public static void WriteLineUnless(bool condition, [InterpolatedStringHandlerArgument(nameof(condition))] ref FalseConditionInterpolatedStringHandler message)
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/// {
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/// if (!condition)
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/// {
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/// Console.WriteLine(message.ToStringAndClear());
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/// }
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/// }
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/// }
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/// </code>
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/// </example>
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/// </summary>
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[InterpolatedStringHandler]
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public struct FalseConditionInterpolatedStringHandler
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{
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private StringBuilder? _builder;
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private StringBuilder.AppendInterpolatedStringHandler _handler;
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/// <summary>
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/// Initializes a new instance of the <see cref="FalseConditionInterpolatedStringHandler"/> struct.
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/// </summary>
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/// <param name="literalLength">The number of constant characters outside of interpolation expressions in the interpolated string.</param>
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/// <param name="formattedCount">The number of interpolation expressions in the interpolated string.</param>
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/// <param name="condition">The condition that determines whether formatting will actually take place.</param>
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/// <param name="shouldAppend">A value indicating whether formatting should proceed.</param>
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/// <remarks>
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/// <para>This constructor is only intended to be called by compiler-generated code.
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/// As such, it doesn't perform argument validation.</para>
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/// </remarks>
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public FalseConditionInterpolatedStringHandler(int literalLength, int formattedCount, bool condition, out bool shouldAppend)
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{
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shouldAppend = !condition;
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if (shouldAppend)
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{
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var builder = new StringBuilder();
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_handler = new(literalLength, formattedCount, builder);
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_builder = builder;
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}
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}
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/// <summary>
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/// Extracts the built string and frees any allocated memory.
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/// </summary>
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/// <returns>The built string.</returns>
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public string ToStringAndClear()
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{
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if (_builder is null)
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{
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return string.Empty;
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}
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var message = _builder.ToString();
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this = default;
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return message;
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}
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/// <inheritdoc cref="StringBuilder.AppendInterpolatedStringHandler.AppendLiteral(string)"/>
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public void AppendLiteral(string value) => _handler.AppendLiteral(value);
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/// <inheritdoc cref="StringBuilder.AppendInterpolatedStringHandler.AppendFormatted{T}(T)"/>
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public void AppendFormatted<T>(T value) => _handler.AppendFormatted(value);
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/// <inheritdoc cref="StringBuilder.AppendInterpolatedStringHandler.AppendFormatted{T}(T, string?)"/>
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public void AppendFormatted<T>(T value, string? format) => _handler.AppendFormatted(value, format);
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/// <inheritdoc cref="StringBuilder.AppendInterpolatedStringHandler.AppendFormatted{T}(T, int)"/>
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public void AppendFormatted<T>(T value, int alignment) => _handler.AppendFormatted(value, alignment);
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/// <inheritdoc cref="StringBuilder.AppendInterpolatedStringHandler.AppendFormatted{T}(T, int, string?)"/>
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public void AppendFormatted<T>(T value, int alignment, string? format) => _handler.AppendFormatted(value, alignment, format);
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/// <inheritdoc cref="StringBuilder.AppendInterpolatedStringHandler.AppendFormatted(ReadOnlySpan{char})"/>
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public void AppendFormatted(ReadOnlySpan<char> value) => _handler.AppendFormatted(value);
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/// <inheritdoc cref="StringBuilder.AppendInterpolatedStringHandler.AppendFormatted(ReadOnlySpan{char}, int, string?)"/>
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public void AppendFormatted(ReadOnlySpan<char> value, int alignment = 0, string? format = null) => _handler.AppendFormatted(value, alignment, format);
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/// <inheritdoc cref="StringBuilder.AppendInterpolatedStringHandler.AppendFormatted(string?)"/>
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public void AppendFormatted(string? value) => _handler.AppendFormatted(value);
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/// <inheritdoc cref="StringBuilder.AppendInterpolatedStringHandler.AppendFormatted(string?, int, string?)"/>
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public void AppendFormatted(string? value, int alignment = 0, string? format = null) => _handler.AppendFormatted(value, alignment, format);
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/// <inheritdoc cref="StringBuilder.AppendInterpolatedStringHandler.AppendFormatted(object?, int, string?)"/>
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public void AppendFormatted(object? value, int alignment = 0, string? format = null) => _handler.AppendFormatted(value, alignment, format);
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}
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#endif

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