Why can't structs be derived from?

[Jonathan M Davis]

On Tuesday, March 15, 2011 14:15:48 Max Samukha wrote:
> On 03/15/2011 10:46 PM, Jens wrote:
> > Daniel Gibson wrote:
> >> Am 15.03.2011 21:29, schrieb Jens:
> >>> Daniel Gibson wrote:
> >>>> Am 15.03.2011 21:07, schrieb Jens:
> >>>>> How is it different in D where all polymorphic objects are
> >>>>> reference types? Take have the design space away, make everything
> >>>>> a glorified pointer and things are better?
> >>>> 
> >>>> They obviously are. Successful languages like Java and C# do it.
> >>>> It's less error-prone and you don't have to worry about
> >>>> dereferencing stuff all the time (sometimes even multiple
> >>>> dereferences at once, like in my example).
> >>> 
> >>> More toward Java-class-language then than C++-level language.
> >>> Sacrificing stack objects was like throwing out sharp knives from
> >>> the kitchen. I understand.
> >> 
> >> If you want value types use structs. Maybe with alias this or mixins
> >> to "extend" them.
> >> Or use emplace (see
> >> http://www.digitalmars.com/d/2.0/phobos/std_conv.html ) with classes
> >> if you wanna play with sharp tools.
> >> It's not like you can't (risk to) cut yourself with D, it's just
> >> easier not to.
> > 
> > While the above was off-topic, I was alluding to class objects on the
> > stack. So not to turn the thread into a critique of the entire language,
> > I'll leave it at that.
> 
> Class objects are possible on stack in D.

Yes, but only with the help of the standard library: std.typecons.scoped. scoped 
classes are going to be removed from the language. It really shouldn't normally 
be the case that a class object is put on the case.

- Jonathan M Davis