EnumHasFlagGenerator.md

Enum HasFlag Generator

Adds the extension method HasFlagNonAlloc to user-defined enums. This custom method provides improved performance compared to System.Enum.HasFlag by avoiding boxing allocations.

Usage

To generate the extension code for enums:

• Declare the PandorityTarget attribute on every assembly that should be visible to the generator
• Apply the System.Flags attribute to the desired enum types

Example

[assembly: PandorityTarget]

[System.Flags]
public enum Element
{
    Fire = 1,
    Water = 2,
    Earth = 4,
    Air = 8,
}

public class GettingStarted
{
    public GettingStarted()
    {
        Element element = Element.Fire | Element.Earth;
        bool hasFire = element.HasFlagNonAlloc(Element.Fire);
        bool hasWater = element.HasFlagNonAlloc(Element.Water);
        bool hasEarth = element.HasFlagNonAlloc(Element.Earth);
        bool hasAir = element.HasFlagNonAlloc(Element.Air);
    }
}

Alternatively, to specify multiple assemblies in one place, create a file named Config.Pandority.additionalfile in the Unity Assets folder and list the assembly names, one per line.

MyAssemblyName
Unity.2D.Common.Runtime
UnityEngine.UI

Limitations

The generated extension method is named HasFlagNonAlloc instead of HasFlag to avoid being hidden by the builtin System.Enum.HasFlag instance method. In C#, instance methods take precedence over extension methods. However, consider that the new name is also clearer about the fact that it is a performance optimization.