Re: [BLACKBOX] foreign COM-objects part 2: inherit multiple interfaces

From: [at]} <Wojtek>
Date: Sat, 18 Dec 2010 22:31:55 -0500

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I heard that multiple inheritance is one of the main reasons that C++ has
severe performance problems in numerical applications. Even if you do not
use multiple inheritance in your code, it is still there biting the
performance.

The performance problems lead to new language constructs, which lead to
new problems, etc. The final outcome was that all problems were eventually
solved, as described in an article published in Computers in
Physics, Volume 11 Issue 3, May/June 1997. The article was titled
"Disambiguated glommable expression templates". After reading that article
I swore I would never touch C++, because I could not understand a single
paragraph. Unfortunately, the article does not seem available online.

I searched the web. As it turns out, the "Disambiguated glommable
expression templates" did not end in 1997. A more recent version is
available:
http://adtmag.com/articles/2000/04/25/disambiguated-glommable-expression-templates-reintroduced.aspx

The first page reads very well, because it cites Stroustrup himself (for
those who do it know what "Stroustrup" means, here is a disambiguated
definintion: Stroustrup == Wirth++). Here is the quote:

"It would be nice if every kind of numeric software could be written in
C++ without loss of efficiency, but unless something can be found that
achieves this without compromising the C++ type system it may be
preferable to rely on Fortran, assembler, or architecture-specific
extensions."

It is nice to hear from Stroustrup that assembler is preferred to C++. I
have never heard such a succicint judgement about C++ qualities.

In any case, I think the article may be worth reading.

I hope these remarks were helpful.

Wojtek


On Sun, 19 Dec 2010, Chris Burrows wrote:

>> -----Original Message-----
>> From: BlackBox [mailto:BLACKBOX{([at]})nowhere.xy
>> gunnar bernhardt (VDI)
>> Sent: Friday, 17 December 2010 7:06 PM
>> To: BLACKBOX{([at]})nowhere.xy
>> Subject: [BLACKBOX] foreign COM-objects part 2: inherit
>> multiple interfaces
>>
>> Am I correct that the reason is that Component Pascal as it is
>> defined in the Language Report (by Oberon) does not allow to
>> inherit from multiple interfaces so there is not easy way to
>> circumvent this?
>>
>
> Way over my head - but I had a look in Clemens Szyperski's (one of the
> co-founders of Oberon microsystems) book "Component Software - Beyond
> Object-Oriented Programming"
>
> http://research.microsoft.com/~cszypers/Books/component-software.htm
>
> In a section on multiple inheritance he states "Microsoft COM does not
> support multiple interface inheritance, but allows a component to support
> multiple interfaces simultaneously, to much the same effect".
>
> His book is worth investigating if you are likely to have a number of
> questions of this sort - many of the examples are in Component Pascal as
> well.
>
> Regards,
> Chris
>
> Chris Burrows
> CFB Software
> http://www.cfbsoftware.com
>
>
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Received on Sun Dec 19 2010 - 04:31:55 UTC