Re: [boost] Re: Object Hierarchies using Interface Types with the BIL

From: Andreas Pokorny (andreas.pokorny_at_[hidden])
Date: 2005-01-01 11:22:38

Hi, 
So the boost interface library implements something like the gnu gcc
signatures? You create proxy classes that forward to non-virtual
methods? 

Regards 
Andreas Pokorny

On Fri, Dec 31, 2004 at 11:09:14AM -0500, christopher diggins <cdiggins_at_[hidden]> wrote:
> ----- Original Message ----- 
> From: "Reece Dunn" <msclrhd_at_[hidden]>
> To: <boost_at_[hidden]>
> Sent: Friday, December 31, 2004 4:26 AM
> Subject: [boost] Re: Object Hierarchies using Interface Types with the BIL
> 
> 
> >christopher diggins wrote:
> >>On the subject of GUI object hierarchies, I wanted to bring to everyone's 
> >>attention the Boost Interfaces Library (BIL) currently being developed by 
> >>Jonathan Turkanis which could be an excellent tool for building a 
> >>flexible and efficient GUI library. There is a brief introduction to the 
> >>library on the Boost wiki ( 
> >>http://www.crystalclearsoftware.com/cgi-bin/boost_wiki/wiki.pl?Boost.Interfaces )
> >>
> >>The code for declaring the interfaces would look like this:
> >>
> >>BOOST_IDL_BEGIN(ILabel)
> >> BOOST_IDL_CONST_FN0(GetText, string)
> >> BOOST_IDL_CONST_FN0(GetAlignment, align_T)
> >>BOOST_IDL_END(ILabel)
> >
> >What I am trying to get working is:
> >
> >15: BOOST_IDL_BEGIN(IUIObject)
> >16:    BOOST_IDL_FN4(move, void, g::metric, g::metric, g::metric, 
> >g::metric)
> >17:    BOOST_IDL_FN2(move, void, g::metric, g::metric)
> >18:    inline void move( g::point p )
> >19:    {
> >20:       move( p.x, p.y );
> >21:    }
> >22: BOOST_IDL_END(IUIObject)
> >
> >with the latest CVS of Boost, but with msvc-8.0, I get:
> 
> >Any suggestions? Is there a version of the BIL that works with the CVS 
> >version (or 1.33) of Boost? And is the above valid, since this is the kind 
> >of thing I want?
> 
> The obvious problem with your code is that the BIL interface is not 
> intended to have any function implementation inside of it. It is in this 
> sense more like a Java interface or a pure abstract base class. So if you 
> want a move functions, I suggest moving them out in a separate class (which 
> I call an extension)
> 
> template<typename T>
> struct IUIObjectWrapper : public T {
>  IUIObjectWrapper() : T() { }
>  inline void move(g::point p) {
>    T::move(p.x, p.y);
>  }
> }
> 
> typedef IUIObjectWrapper<IUIObject> IUIObjectExtension;
> 
> This approach actually corrects what I percieve to be a huge flaw with many 
> object libraries, which is the coupling of core functionality and derivable 
> functionality.
> 
> Also note that a new version of the BIL library is due out in a few days.
> 
> Christopher Diggins
> http://www.cdiggins.com
> http://www.heron-language.com 
> 
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