On 10/03/2015 17:38, Steven Watanabe wrote:
AMDG
On 03/10/2015 07:33 AM, Mathias Gaunard wrote:
On 08/03/2015 05:27, Steven Watanabe wrote:
The calls to register_binding are necessary for this to work, unfortunately. I don't think it's possible to implement dynamic_any_cast without some kind of registration, but at least it only needs to be called once for each concept/type combination. If anyone has any better ideas about how to handle this, I'd love to hear it.
If you're doing this, you might as well implement full dynamic duck typing. If the expression is valid, you call it, otherwise you raise an exception.
Oh, I agree. However, the cost of such a call is significantly greater then a normal virtual call. Thus, I don't want the library to do this without being told explicitly that it's the desired behavior. With what I have already, the implementation of such a feature is trivial. The real issue is defining the interface for it.
How about something like this: any a; duck_visit(f, a); with 'f' a polymorphic function object constrained with SFINAE. if f(a) is callable for the dynamic type of a, then call it, otherwise raise an exception.