On Thursday, 11 December 2014 at 13:55:55 UTC, Marc Schütz wrote:
On Thursday, 11 December 2014 at 12:48:05 UTC, Manu via Digitalmars-d wrote:
On 8 December 2014 at 07:29, Walter Bright via Digitalmars-d
<[email protected]> wrote:
On 12/7/2014 6:12 AM, Dicebot wrote:

But from existing cases it doesn't seem working good enough. For example,
not
being able to represent idiom of `scope ref int foo(scope ref int x) {
return x;
}` seems very limiting.


 scope ref int foo(ref int x);

will do it.

Will it? It looks like foo can't be called with scope data?

This is a point that most people don't seem to understand yet, and which wasn't obvious for me either, at the beginning:

* A `ref` parameter means that it cannot escape the function, _except_ by return. * A `scope ref` parameter means that it cannot escape the function _ever_, not even by return. * A `scope ref` return means that it cannot leave the current statement.

Therefore, a `scope ref` return value can be passed on to the next function as a `ref` argument. If that function again returns a reference (even if not explicitly designated as `scope`), the compiler will treat it as if it were `scope ref`.


OH! I had totally misunderstood that. Cheers for the explanation.

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