On Friday, 18 May 2018 at 12:16:55 UTC, aliak wrote:
You may not need a new word at all. You can also enhance
private to take arguments. Package already does this. You can
give private a symbol list that says which symbols this is
private for. So:
class A {
private int x;
private(A) int y;
}
void main() {
A a = new A();
a.x = 7; // ok, it's private to module
a.y = 3; // error, it's sealed to class
}
That's actually a decent way to go about it. It matches the
package syntax and avoids new keywords. It's also not as onerous
as repurposing an existing keyword (like `module`), nor does it
cause any breakage. Though, I would argue that rather than
allowing any old symbol, it be restricted to `this`:
private(this) int y;
This keeps the implementation simple and the scope focused. If a
DIP were put forward, I think this would be the approach to take.
Though a fairly strong case will still need to be made as to why
this is beneficial (use cases, example code, etc). To bolster the
case, I would look at the reasoning behind the recommendation in
Java that classes use the public API internally rather than
manipulating member variables directly to improve maintainability.
