C# at least supports the notion of partial classes that can have their definition spread over multiple files: https://learn.microsoft.com/en-us/dotnet/csharp/pr

C# at least supports the notion of partial classes that can have their definition spread over multiple files: https://learn.microsoft.com/en-us/dotnet/csharp/programming-guide/classes-and-structs/partial-classes-and-methods https://learn.microsoft.com/en-us/dotnet/csharp/programming-... Ruby has mixins and Python supports multiple inheritance. Go encourages composition over deep nested hierarchies. Many main stream languages support this kind of functionality.