Re: The Failure of OOP

From: christopher diggins (cdiggins_at_videotron.ca)
Date: 04/14/04

  • Next message: thoff: "Re: xp and simple design" 
    Date: Wed, 14 Apr 2004 07:21:36 -0400

    "Calum" <calum.bulk@ntlworld.com> wrote in message
    news:c5iu9g$2mm$1@news6.svr.pol.co.uk...
    > christopher diggins wrote:
    > > Hi Calum, thanks for reporting these results! This is encouraging for me
    to
    > > see. This helps to support my claim that there are gains to be had when
    > > modeling with interfaces as opposed to ABC's. I am currently working on
    a
    > > matrix test case. Many people seem to be put-off by the Int and NaiveInt
    > > example because it appears too degenerate. I am hoping that a matrix
    example
    > > will be easier to relate to. Thanks again.
    >
    > It's definitely a good idea to test this further. I think you will get
    > very different results depending on how you slice the cake - and you
    > could definitely rig something that will show interfaces in your favour.
    > But that is obviously not the point.
    >
    > As I understand things the tradeoffs are:
    >
    > ABC Interface
    > Object size larger smaller
    > Pointer size smaller larger

    And the following:

    - objects that implement interfaces perform bettter than comparable objects
    inheriting ABC's when not referenced
    - interface pointer size styas constant with regards to the number of
    intefaces implemented where ABC's cause an expansion for each inherited
    base.

    > The problem comes when you have a pointer to an interface, not an
    > object. In general, you would expect to have more pointers than
    > objects, which means that interfaces could consume more memory. e.g. in
    > a matrix class, you would presumably have a vector of INumeric, 8 bytes
    > each.

    In some scenarios you would have more pointers than objects, but I am not
    sure it is a safe generalization. I have used and written many designs that
    use objects more than pointers. The other important point is that we need to
    compare the number of concrete pointers (which are not impacted in the
    proposal) with the number of base pointers. The goal is to allow specific
    designs to exist that do not exhibit unacceptable runtime penalties and code
    bloat.

    > And where would you "own" the numbers themselves, or would they be in a
    > seperate array?

    This depends entirely on the design of the software. Both approaches are
    valid.

    > Could you have the facility for an interface to delete
    > its object - that is something you could not do with multiple
    > inheritance I think.
    >
    > Calum

    I do not see how this would be a problem, an object could simply to provide
    an interface IDestructible that provides a destructor as an explicit named
    function.

    Thanks for your feedback. 

    -- 
Christopher Diggins
http://www.cdiggins.com
http://www.heron-language.com
  • Next message: thoff: "Re: xp and simple design"

    Relevant Pages

    • Re: Passing Smart Pointers as Parameters
      ... How do you obtain interface pointers on your own object? ... It's not the problem with the interfaces on my object. ... debug output... ... should see the debug output, ...
      (microsoft.public.vc.atl)
    • Re: What I dont like about C# so far, compared to C++ (managed or otherwise)
      ... 1/ no pointers or tracking pointers or handles--this is absurd. ... order to support them. ... In what way aren't interfaces supported? ... inheritance of interface and single inheritance of implementation. ...
      (microsoft.public.dotnet.languages.csharp)
    • Re: The Failure of OOP
      ... > Hi Calum, ... could definitely rig something that will show interfaces in your favour. ... The problem comes when you have a pointer to an interface, ...
      (comp.object)
    • Re: Does IUnknown pointer comparison work across process boundarie
      ... Many thanks Igor, thats the gist of what I am asking. ... These interface pointers would arrive in theObjectComparer.exe process via ... the interfaces passed to SetObject1() and SetObject2 ...
      (microsoft.public.win32.programmer.ole)
    • Re: Problem with multiple video renderer in a graph
      ... querying IVideoWindow from IBaseFilter. ... The first thing you should do is use smart COM pointers for your ... interfaces. ...
      (microsoft.public.win32.programmer.directx.video)
    Loading