Jonathan M Davis Wrote: > On Wednesday, December 01, 2010 14:32:12 bearophile wrote: > > foobar: > > > 1. static_cast: > > > a. Remove ALL implicit coercions inherited from c such as double -> > > > int, b. I don't see the need for an operator for conversions since > > > they can have different parameters, e.g.: - converting to string can > > > have formatting specified > > > - converting string to numeric types with optional base parameter > > > - converting integer to floating point specifies > > > round/floor/ceiling/etc.. > > > > > > 2. const_cast: should be a _separate_ operator in order to prevent > > > removing const by mistake. > > > > > > const Base obj1 = new Derived(); > > > auto obj2 = cast(Derived)(obj1); // oops: meant to only down cast > > > > > > 3. dynamic_cast: the language should provide a down cast operator for OO. > > > 4. reinterpret_cast: unsafe and should be restricted as much as possible > > > (Not available in @safe code) maybe not provide it at all since it's > > > implementable via union. A restricted library solution for when you > > > really want to play with bits and bytes? > > > > There are some ideas here, like the separation from const_cast, dynamic > > cast, and other casts. In past I too have asked for something similar, but > > I think Walter was not interested. > > > > I guess the idea of having a single cast is to keep the language simple. > > But those _are_ different kinds of casts, they have different semantics. > > Lumping different semantics into the same syntax is not a good way to > > simplify a language, in my opinion. It just creates obscurity and maybe > > some other troubles too. > > And how many programmers do you know who actually, really know the > differences > between the 4 C++ cast types. _I_'m not sure that _I_ know, and I've studied > it. > And honestly, in most cases - if not in _all_ cases - as far as I can tell, > the > compiler should be able to determine the correct cast type. So, forcing that > on > the programmer is just stupid. If you actually _need_ separate cast types, > then > we should have them, but if we can avoid that, we definitely should. I think > that > the fact that C++ has so many types of casts is horrible. I try and use them > correctly, but I don't think that there are very many programmers (percentage- > wise at least) who do. I know plenty of programmers who just use C-style > casts > everywhere. > > - Jonathan M Davis
My suggestion is much simpler than c++. the _language_ needs only to provide two operators: down cast operator and const cast operator. interpret cast is a corner case that can also be implemented as a library utility. conversions can and should be done with regular D code (functions). which is not far from current D idioms (to!).
