const after initialization / pointers, references and values

[Jakob Ovrum via Digitalmars-d]

On Wednesday, 20 August 2014 at 21:26:55 UTC, Philippe Sigaud via 
Digitalmars-d wrote:
> If you want reference semantics but do not want to have 
> pointers in
> your code, yes classes are your best choice.

Certainly the easiest, but I don't think it's always the best. If 
light-weightedness is desired, make the struct contain the 
reference, effectively making the struct a reference type:
---
private struct Data
{
     int a;
     string b;
     double c;
}

/// Lorem ipsum ...
struct UserFacingType
{
     private Data* data;
     // use data.foo
}
---
Of course, this means UserFacingType.init is essentially `null`, 
just like class references. By using std.typecons.RefCounted, the 
user-facing type can also easily be made a reference-counted 
reference.

Structs can do everything classes can with enough boilerplate. 
Leverage templated types like RefCounted to remove the 
boilerplate. Classes are just an in-built convenience feature to 
handle the boilerplate of virtual functions.