tupleof seems to break encapsulation

[Jacob Carlborg]

On 2020-09-04 12:16, 60rntogo wrote:
> Consider the following code.
> 
> foo.d
> ---
> module foo;
> 
> struct Foo
> {
>    private int i;
> }
> ---
> 
> main.d
> ---
> void main()
> {
>    import std.stdio;
>    import foo;
> 
>    auto x = Foo();
>    writeln(x);
>    // ++x.i;
>    ++x.tupleof[0];
>    writeln(x);
> }
> ---
> 
> As expected, the commented line does not compile. If I uncomment it, I 
> get the error "no property i for type foo.Foo". However, the rest of the 
> code compiles just fine and outputs:
> ---
> Foo(0)
> Foo(1)
> ---
> 
> This appears to defeat the purpose of declaring i private. What am I 
> missing?

It's useful for serialization and, as you can see in your example, for 
debugging as well. `writeln` will print the values of the fields in a 
struct, even for private fields.

-- 
/Jacob Carlborg