foobar Wrote: > IMHO, coercions in D should be redesigned. They are a tiny bit better than C > but C is a weekly (and poorly) typed language. I personally prefer the > properly strongly typed ML family of languages. > > My preference is as follows: > 1. static_cast: > a. Remove ALL implicit coercions inherited from c such as double -> int,
Done > 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.. This was kind of my point, to! already specifies how to generically (an important part) to other types. And opCast overrides everything (which I don't wish to claim is incorrect, just asking). > 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 I think to! should be changed such that this would be a ConvException. > 3. dynamic_cast: the language should provide a down cast operator for OO. Then the example above is invalid, though still valid when casting const double to int... > 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? > > the above means that: > double pi = 3.14; > int p = pi; // compile-time error Currently is an error. > int p = floor(pi); // ok Maybe std.math.floor should return an int, since they are implicitly converted to real... > and also: > int x = ??; // some number > double y = x; //compile-time error > double z = double(x); // explicit Other than overflow, which isn't fixed if made explicit, I don't see an issue with it being implicit. > double r = 5 / 2; // compile error Well this might be one, if 5 and 2 are variables. > choose either: > a. double r1 = double(5/2); // 2.0 > b. double r2 = double (5) / 2; // 2.5 Assuming variables here, wouldn't that need to be: double r2 = cast(double) 5 / cast(double) 2; // not implicit casting remember.
