Re: [Boost-users] [Boost.Parameter] How to Use Named Parameters in a Class Hierarchy?

From: Gottlob Frege (gottlobfrege_at_[hidden])
Date: 2006-10-27 19:32:29

On 10/26/06, Wu Yinghui, Freddie <yhwu_at_[hidden]> wrote:
>
>
> My situation is like this:
>
> I have a class hierarchy briefly shown as below (assuming virtual member
> function template is allowed, just to demonstrate the idea):
> ===== CODE =====
> class Base
> {
>    //...
>
>    // This is the function that makes use of Boost.Parameter
>    template <typename ArgumentPack>
>    virtual void Configure(ArgumentPack const &arguments) = 0;
> };
>
> // This class resides in Derived1.dll
> class Derived1 : public Base
> {
>    template <typename ArgumentPack>
>    void Configure(ArgumentPack const &arguments)
>    {
>       //...
>    }
> };
>
> // This class resides in Derived2.dll
> class Derived2 : public Base
> {
>    template <typename ArgumentPack>
>    void Configure(ArgumentPack const &arguments)
>    {
>       //...
>    }
> };
> ===== CODE =====
>
> To use the class hierarchy, my program loads the DLL requested by user
> using LoadLibrary() (We're using Windows, but it should be similar to
> Linux, I suppose), and makes use of the Derived1/Derived2 classes via a
> pointer to the Base class.
>
> Since I have no information about the derived classes when building my
> main executable (only Base class is known then), I cannot make direct
> use of Derived1/Derived2 types in my main program. -- Yet, I need a way
> to provide some arbitrary set of arguments to the derived classes.
>
> Hope my explanation clears your doubts. Do you have any suggestion or
> alternative design in mind?

Pass your params packaged in a adobe::dictionary_t (opensource.adobe.com) or
something like that - not sure what the boost equivalent is.

Cheers,
>
> Freddie

Tony