Dynamic polymorphism - explanation

[macky]

You're right! Serialization is just one of the benefit comming from this. But I'm planing to do something even more interesting. I'm trying to port my DAL (data access layer) into d and share it with d community. I was planning to bind it to ddbi. From my experiances this is the most convinient way of handling data in a bussiness application (transaction pattern). Unfortunately I'm having a hard time accessing fields dynamicaly. I also miss some meta parameters (c# is really handy), but this is not as much of an issue. Anyway if I embeded tupleof in a class itself (similar to your suggestion) it does not return it's own fields. *doh*. I'm a bit of stuck here. In order to do what I have planned I to access fields somehow.

cheers, martin


Jarrett Billingsley Wrote:

> "macky" <martin.butina at gmail.com> wrote in message 
> news:evnbo3$30r2$1 at digitalmars.com...
> >
> > ah. sorry. Classes are empty due to my lazyness ;). Actualy there are some 
> > virtual methods defined in a base class but some members are are defined 
> > just in a derived class. My idea was that I would get this members with 
> > tuppleof function (I guess I'm trying to fake the reflection). These 
> > members do not exist in a base class ofcourse but my question is if this 
> > is possible the way I wanted to perform this task... Since my 
> > DoSomething() function is expecting the base class and in implementation I 
> > have provided the derived class I would expect that it is handled as a 
> > derived class. But I realize that this derived class is cast in a base 
> > class and therefor no member is returned. I would like to avoid this but I 
> > don't know how. I thought that I'm not using input parameters correctly?
> >
> > regards, Martin
> 
> Ah, I see now.  Depending on what you're trying to do, tupleof might be 
> unnecessary.  You could design it the other way around, like so:
> 
> class BaseClass()
> {
>     ...implementation of interface...
> 
>     // To be overridden
>     void processMe(Process p);
> }
> 
> class Customer() : BaseClass
> {
>    ...some members and overriden baseclass functions...
>     void processMe(Process p)
>     {
>         // do the processing
>     }
> }
> 
> class Process()
> {
>     void DoSomething(BaseClass object)
>     {
>         // this will call the appropriate process method based
>         // on the derived class type
>         object.process(this);
>     }
> }
> 
> But that you want to access data fields of classes and not just the methods 
> makes me think you want to do something more complex, like .. serializing 
> the members of a class to a file?  I'm wondering why you want to access to 
> the data fields of the class. 
> 
>