https://github.com/Spinnernicholas/EnumFastToStringDotNet

This is a Visual Studio C# source generator for automatically generating enum extension methods that implement a switch expression based ToString method. Why? The default enum ToString method implements a binary search which is great for large lists but becomes time and memory inefficient for a just a few items when compared to a switch expression.
https://github.com/Spinnernicholas/EnumFastToStringDotNet

csharp csharp-sourcegenerator dotnet roslyn

Last synced: about 2 months ago
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This is a Visual Studio C# source generator for automatically generating enum extension methods that implement a switch expression based ToString method. Why? The default enum ToString method implements a binary search which is great for large lists but becomes time and memory inefficient for a just a few items when compared to a switch expression.

• Host: GitHub
• URL: https://github.com/Spinnernicholas/EnumFastToStringDotNet
• Owner: Spinnernicholas
• Created: 2021-08-26T18:14:35.000Z (about 3 years ago)
• Default Branch: main
• Last Pushed: 2022-03-28T19:58:00.000Z (over 2 years ago)
• Last Synced: 2024-05-12T12:39:45.854Z (4 months ago)
• Topics: csharp, csharp-sourcegenerator, dotnet, roslyn
• Language: C#
• Homepage:
• Size: 28.3 KB
• Stars: 31
• Watchers: 3
• Forks: 2
• Open Issues: 1
• Metadata Files:
  • Readme: README.md

Awesome Lists containing this project

• RSCG_Examples - EnumFastToStringDotNet
• csharp-source-generators - EnumFastToStringDotNet -   - Automatically generates enum extension methods that implement a switch expression based ToString method. (Source Generators / Enums)

README

        
# EnumFastToStringDotNet

This is a Visual Studio C# source generator for automatically generating enum extension methods that implement a switch expression based ToString method. Why? The default enum ToString method implements a binary search which is great for large lists but becomes time and memory inefficient for a just a few items when compared to a switch expression. Binary search has an O(log n) while a switch expression in this case has a O(1).

You can thank [Nick Chapsas](https://github.com/Elfocrash) on YouTube for making me aware of this. Check out his awesome video here: [C#'s Enum performance trap your code is suffering from](https://www.youtube.com/watch?v=BoE5Y6Xkm6w)

## Benchmark

Benchmark done with [BenchmarkDotNet](https://benchmarkdotnet.org/). You can run it for yourself by opening the solution in Visual Studio and running the samples/Benchmark project.

```

|                         Method |      Mean |     Error |    StdDev |  Gen 0 | Allocated |

|------------------------------- |----------:|----------:|----------:|-------:|----------:|

|                 NativeToString | 25.871 ns | 0.5217 ns | 0.4625 ns | 0.0057 |      24 B |

|        SwitchStatementToString |  1.265 ns | 0.0512 ns | 0.0479 ns |      - |         - |

|       SwitchExpressionToString |  1.399 ns | 0.0565 ns | 0.0529 ns |      - |         - |

| EnumFastToStringDotNetToString |  1.510 ns | 0.0224 ns | 0.0175 ns |      - |         - |

```

## Quick Start

1. Add source generator reference to your project

```xml

  

    

  

```

2. Add using statement

```c#

using EnumFastToStringGenerated;

```

3. Add [FastToString] attribute to your enum

```c#

[FastToString]

public enum HumanStates

{

    Idle,

    Working,

    Sleeping,

    Eating,

    Dead

}

```

4. Call FastToString method

```c#

Console.Out.WriteLine(HumanStates.Dead.FastToString());

```

5. The Automatically Generated Code

```c#

using System;

namespace EnumFastToStringGenerated

{

    public static class EnumExtensions

    {

        public static string FastToString(this Namespace.HumanStates states)

        {

            return states switch

            {

                Namespace.HumanStates.Idle => nameof(Namespace.HumanStates.Idle),

                Namespace.HumanStates.Working => nameof(Namespace.HumanStates.Working),

                Namespace.HumanStates.Sleeping => nameof(Namespace.HumanStates.Sleeping),

                Namespace.HumanStates.Eating => nameof(Namespace.HumanStates.Eating),

                Namespace.HumanStates.Dead => nameof(Namespace.HumanStates.Dead),

                _ => throw new ArgumentOutOfRangeException(nameof(states), states, null)

            };

        }

    }

}

```

## Custom Method Name

If you would like to use a different method name, you can do so with the attribute argument "MethodName".

```c#

[FastToString(MethodName = "CustomMethodName")]

public enum HumanStates

{

    Idle,

    Working,

    Sleeping,

    Eating,

    Dead

}

```

Then you can call the method like this:

```c#

Console.Out.WriteLine(HumanStates.Dead.CustomMethodName());

```

## Customizing Source Generator

You can customize the source generator by changing the const values in the EnumSwitchSourceGenerator.cs file.

```c#

//The namespace that the attribute and extension method classes are defined in

private const string NAMESPACE = "EnumFastToStringGenerated";

//The name of the attribute

private const string ATTRIBUTE_NAME = "FastToString";

//The name of the extension method

private const string EXTENSION_METHOD_NAME = "FastToString";

```