On 01/04/2017 2:34 PM, Andrei Alexandrescu wrote:
Walter and I discussed the following promising setup:
Use "throw new scope Exception" from @nogc code. That will cause the
exception to be allocated in a special stack-like region.
If the catching code uses "catch (scope Exception obj)", then a
reference to the exception thus created will be passed to catch. At the
end of the catch block there's no outstanding reference to "obj" so it
will be freed. All @nogc code must use this form of catch.
If the catching code uses "catch (Exception obj)", the exception is
cloned on the gc heap and then freed.
Finally, if an exception is thrown with "throw new Exception" it can be
caught with "catch (scope Exception obj)" by copying the exception from
the heap into the special region, and then freeing the exception on the
heap.
Such a scheme preserves backward compatibility and leverages the work
done on "scope".
Andrei
I love it!
Could we also have some way to force scope when throwing?
interface ScoppedThrowable {}
class MyException : Exception, ScoppedThrowable { ... }
throw new MyException;
