Old problem with performance

[Weed]

Weed пишет:
> Bill Baxter пишет:
>> On Sun, Feb 22, 2009 at 1:02 AM, Weed <resume755 at mail.ru> wrote:
>>> Bill Baxter пишет:
>>>> 2009/2/21 Weed <resume755 at mail.ru>:
>>>>> Weed пишет:
>>>>>> Bill Baxter пишет:
>>>>>>
>>>>>>> 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++?