Union Generator

Simplifies the construction of discriminated unions using records. It also includes an analyzer to ensure correct usage.

// Makes `BoxedValue` abstract
[Union]
public partial record BoxedValue
{
    // Each entry becomes `public sealed partial record`
    partial record StringValue(string Value);
    partial record IntValue(int Value);
}

This grants BoxedValue some new powers.

• BoxedValue.[Member].Of: A static function alias for the constructor that returns the base type. Useful for inference.

  // Does not compile
  var value = true ? new BoxedValue.StringValue("One") : new BoxedValue.IntValue(2);
  
  // Compiles
  var value = true ? BoxedValue.StringValue.Of("One") : BoxedValue.IntValue.Of(2);

• BoxedValue.[Member].λ: A Func version of the above, see the [Lambda] generator.
• BoxedValue.Match: A function for exhaustive matching on the union's members, see the [EnumMatch] generator.

  var matched = value.Match(
    StringValue: sv => $"string:{sv.Value}",
    IntValue: iv => $"int:{iv.Value}");