Old problem with performance

[naryl]

Weed Wrote:

> Weed �����:
> > Bill Baxter �����:
> >> On Sun, Feb 22, 2009 at 1:02 AM, Weed <resume755 at mail.ru> wrote:
> >>> Bill Baxter �����:
> >>>> 2009/2/21 Weed <resume755 at mail.ru>:
> >>>>> Weed �����:
> >>>>>> Bill Baxter �����:
> >>>>>>
> >>>>>>> Why don't you just show us the class in the way you would like to
> >>>>>>> write it in C++, and we'll show you how to write it in D, or finally
> >>>>>>> agree with you that it's not possible.   But as long as you continue
> >>>>>>> to be hand-wavy about "common base classes" we're at a bit of an
> >>>>>>> impasse.  So far everyone thinks D can do what you want it to do based
> >>>>>>> on your vague descriptions.
> >>>>> As I said, you can write everything using "goto" and "if".
> >>>>>
> >>>>> ...But why you do not like the original example of this thread?
> >>>> Please post again.  I don't seem to recall any detailed example.
> >>>>
> >>>> --bb
> >>> http://www.digitalmars.com/pnews/read.php?server=news.digitalmars.com&group=digitalmars.D&artnum=83506
> >> You should use a struct there!   Your code does not show you doing
> >> anything that would even remotely suggest using a class is worthwhile.
> >>  You're doing value operations on value types.  That's what structs
> >> are for.
> >  	
> > Why?
> > 
> > What if I have not substantiated the fact that c1 is a class I should
> > use there a structure?
> > 
> > Used in D a model of placement classes only in heap have a rule "if you
> > made the class and trying to pass it by value is somewhere in your code,
> > there is a design error?
> 
> Explains why the question is given in this form:
> 
> I am received or wrote a classes. Is it right to overload the operator
> opAdd and use them? I think yes.
> 
> But why not allow this operation at the same speed that allows C++?

If you pass it by value you'll lose polymorphism. That must mean that you inherit that class only to avoid duplicating code. And that is easily done with template mixins.