Sealed classes - would you want them in D?

[Dukc]

On Tuesday, 15 May 2018 at 06:38:04 UTC, KingJoffrey wrote:
> Can you give me some examples?

Defining a Voldemort type (meaning, one whose name is not public) 
with private members for use by multiple functions:

-------
module two_functions;

private struct MyForwardRange
{   private int function(int[]) cumulator;
     int[] front;
     void popFront()
     {   front ~= cumulator(front);
     }
     enum empty = false;
     auto save()
     {   return this;
     }
}

auto accumulate(int a, int b)
{   import std.algorithm;
     return MyForwardRange(arr => arr.sum, [a, b]);
}

auto extendByIota(int[] startElems)
{   return MyForwardRange(arr => arr.length, startElems);
}
-------

In a simple module like this, it would be needless complexity to 
make cumulator have a package visibility and put the functions in 
a different module. That's what you would have to do if private 
meant private to class, not to module.