Calypso and the future of D

[Andrei Alexandrescu via Digitalmars-d]

On 1/23/15 10:27 AM, Elie Morisse wrote:
> Exception catching is next after the first light of my Ogre3D demo,
> Clang will probably simplify handling of C++ exceptions a lot.

On that front, a coworker gave me a simple idea for integration.

1. All C++ non-polymorphic types thrown cannot be caught in D

2. We (or Calypso) define D class counterparts for polymorphic types 
thrown from C++, notably std::exception and subtypes. N.B. those are D 
classes, not D structs

3. D code can catch std::exception. The only caveat is that the caught 
exception cannot survive the catch statement. Given that calling into 
C++ is not the paramount of safety in the first place, I'd say that's a 
reasonable compromise.

Example:

----
import core.stdcpp.vector;
import core.stdcpp.exception;

core.stdcpp.exception g;

void fun(core.stdcpp.vector!int v)
{
     try
     {
         v.push_back(42);
     }
     catch (core.stdcpp.exception e) // fine, can catch
     {
         g = e; // ouch, will dangle
     }
}
----

Thoughts?


Andrei