beakona / AutoInterface

C# interface-to-member source generator

AutoInterface

C# Source Generator which redirects all interface-calls to one or more backing members. Source code can be generated for a class, record, or struct. It can be generated automatically or by a custom template (scriban, liquid).

Manually written source:

interface IPrintable
{
   void Print();
}

public partial class Person : IPrintable
{
   [BeaKona.AutoInterface]
   private readonly IPrintable aspect1 = new PersonPrinterV1();
}

Auto-generated accompanying source:

partial class Person
{
   void IPrintable.Print() => this.aspect1.Print();
}

Ad-hoc adapter pattern

In this example PersonPrinterV1 does not implement IPrintable but does have all members that are required by that interface.

Manually written source:

interface IPrintable
{
   void Print();
}

class PersonPrinterV1
{
   void Print() { ... }
}

public partial class Person
{
   [BeaKona.AutoInterface(typeof(IPrintable))]
   private readonly PersonPrinterV1 aspect1 = new PersonPrinterV1();
}

Auto-generated accompanying source:

partial class Person : IPrintable
{
   void IPrintable.Print() => this.aspect1.Print();
}

Generate code from a template

Manually written source:

interface IPrintable
{
   void Print();
}

public partial class Person : IPrintable
{
   // add file mytemplate.scriban in your VS project
   // and set it's build action to: 'C# analyzer additional file'
   [BeaKona.AutoInterface(TemplateFileName = "mytemplate.scriban")]
   private readonly IPrintable? aspect1 = null;
}

Auto-generated accompanying source:

partial class Person
{
   ..generated from file..
}

Partial template

Partial template can be defined inline (from string) or from file.

Manually written source:

interface IPrintable
{
   int Length { get; }
   int Count { get; }
   void Print1();
   void Print2();
}

public partial class Person : IPrintable
{
   private void LogDebug(string name) { }

   [BeaKona.AutoInterface]
   [BeaKona.AutoInterfaceTemplate(BeaKona.AutoInterfaceTargets.PropertyGetter,
        Filter = "Length", Language = "scriban", Body = "return 1;")]
   [BeaKona.AutoInterfaceTemplate(BeaKona.AutoInterfaceTargets.Method,
        Filter = "Print(\\d)?", Body="LogDebug(nameof({{interface}}.{{name}})); {{expression}};")]
   private readonly IPrintable? aspect1 = new PrinterV1();
}

Auto-generated accompanying source:

partial class Person
{
   int IPrintable.Length
   {
      return 1;
   }
   
   int IPrintable.Count => this.aspect1!.Count;

   void IPrintable.Print1()
   {
       LogDebug(nameof(IPrintable.Print1));
       this.aspect1!.Print1();
   }

   void IPrintable.Print2()
   {
       LogDebug(nameof(IPrintable.Print2));
       this.aspect1!.Print2();
   }
}

Other examples can be found in wiki.

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