Jesse Phillips Wrote:
> foobar Wrote:
>
>
> > > > - 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).
> > >
> >
> > I don't follow as to how this is important to have a generic interface. Can
> > I specify parameters for conversion with to! as in my examples?
> > I'd appreciate an example
>
> Oops, sorry, though I don't see why it can't be specified in to!.
>
how would the to! usage look like with these additions? I suspect at that stage
the benefits of to! genericity will be lost.
to!(int)("1010101", 2); / base 2 ?
to!(int)(3.14, ..); // how do you specify a floor strategy here, enum?
this quickly gets messy, ugly and redundant.
int a = floor(3.14); // KISS - much better
> > > > 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.
> >
> > This should not even compile. a run-time exception is better than current D
> > but is still very weak.
>
> See my bug report, http://d.puremagic.com/issues/show_bug.cgi?id=5307
>
> After making it a runtime error, I made it just not compile. (Error message
> sucks though.)
good :)
>
> > > > 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...
> >
> > a down cast should _only_ perform dynamic down casts in the OO sense. so:
> > Base foo = new Derived;
> > Derived bar = downCast(foo); // compiles. performed at run-time
> >
> > [const] double -> int is not a down cast, it is a conversion.
>
> I was referring to the need for const_cast
Sorry, I lost you here. what are you talking about here?
>
> > > 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.
> >
> > besides the overflow issue you have mentioned, I also don't want special
> > cases. No implicit conversions should be applied equally everywhere.
>
> Then be explicit in all of _your_ code. That won't stop others from using
> implicit conversion, but you can just assume they are of the same type and be
> fine.
>
since the entire point is to prevent bugs by having compiler checks, I don't
see how the above conclusion helps me at all. I want the compiler to prevent me
from getting the kinds of bugs previously shown.
