RE: Time to rewrite dpkg

[Brent Fulgham <bfulgham@xpsystems.com>]

> * Ossama Othman said:
> 
> >  > Why? Tell me how I pass a C++ object to C, Fortran or Pascal. 
> > 
> > The same way you pass fortran to C: use wrappers, for 
> example.  Here is
> > one way of passing a static C++ method to a C function (e.g. signal
> > system call) in C++ code:
> > 
> > extern "C" void
> > Base_cleanup (void *object, void *)
> > {
> >   Base::cleanup (object, 0);
> > }
> > 
> > Simple. :-)
> Perhaps, but not clean. And doesn't make sense in this 
> particular case...
> Remember the rule of the Ockham's Razor???? I think it should 
> be obeyed
> here...
> 

I think the real problem is in trying to export a language-specific
construct to another language which does not support it.  C does not support
objects.  Yes, yes.  I realize that a "good C programmer can bliff and
blaff, etc., to achieve an object-oriented design that will be worthy of a
Nobel prize and the Pulitzer prize simultaneously, etc. etc.".

However, the fact is that C is designed primarily for procedural style
programming, and does not have features in place to handle
C++/Java/Python/etc. objects.

A better question is how a revised C++-ish library might interoperate with
an object-oriented language designed to make use of polymorphism,
abstraction, etc.  Say, how Python might work as a front end, or how you
might use Java, etc.

Asking how to pass a C++ object to C is like asking how to cast a float to a
byte field in assembly.  

Ideally, a library would (in addition to it's C++ functionality) have a C
interface that doesn't really deal with the issue of objects.  Say,
something that would accept some standard C types and structs, and return
same.

-Brent