Very simple null reference escape

[Paul Backus]

On Sunday, 2 June 2019 at 07:55:27 UTC, Amex wrote:
> A.B
>
> If A is null, crash.
>
> A?.B : writeln("HAHA");
>
> No crash, ignored, equivalent to
>
> if (A is null) writeln("HAHA"); else A.B;

The "optional" package on dub [1] has a .dispatch method that 
does this:

     auto d = some(A());

     // Dispatch to one of its methods

     d.dispatch.f(); // calls a.f, returns some(4)
     d.dispatch.inner.g(); // calls a.inner.g, returns some(7)

     // Use on a pointer or reference type as well
     A* e = null;

     // If there's no value in the reference type, dispatching
     // works, and produces an optional
     assert(e.dispatch.f() == none);
     assert(e.dispatch.inner.g() == none);


Full example: https://run.dlang.io/is/SmsGQu

[1] https://code.dlang.org/packages/optional