Motivation:
 Time and again project that requires efficient containers, either hand
codes each case or writes a code generating pre-processor.
  All C++ books I could find, use only very simplified container models
and/or sacrifice efficiency by generating non-intrusive containers.
  While there are many programs where non-intrusive containers are
fine, or even advantageous, there are many application where one can not
afford the extra space nor time they take.
  I see no _elegant_ way to use current C++ mechanisms to build, for
example, link lists where parent can own more than one list of
children, and a child can be in different parent lists.

Proposal:
  Enhance templates to allow identifiers as parameters. At least some
identifiers as in the example below.

// slist.c   example of use
class Pin; class Comp; class Net;

template<class Parent, class Child, Child* first, Child* next > class Slist {
 public:
   static inline void add(Parent* par, Child* chi) {chi->next= par->first;
          par->first= chi;  }
   //del(), iterate(), whatever()...procedures for parent/child slists
};

class Comp {
   Pin* iFirst;    // for input  pin list
   Pin* oFirst;    // for output pin list
 public:
   friend class Slist<Comp, Pin, iFirst, nextByComp>;
   friend class Slist<Comp, Pin, oFirst, nextByComp>;
};

class Pin {
   Pin* nextByComp;
   Pin* nextByNet;
 public:
   friend class Slist<Comp, Pin, iFirst, nextByComp>;
   friend class Slist<Comp, Pin, oFirst, nextByComp>;
   friend class Slist<Net,  Pin, first,  nextByNet>;
};

class Net {
   Pin* first;  // for list of pins in this net
 public:
   friend class Slist<Net,  Pin, first,  nextByNet>;
};

main() {

 Slist<Comp, Pin, iFirst, nextByComp> compIPin;
 Slist<Comp, Pin, oFirst, nextByComp> compOPin;
 Slist<Net,  Pin, first,  nextByNet > netPin;

 Comp* comp;
 Net*  net;
 Pin*  pin;
 //...
 compIPin.add(comp,pin);
 netPin.add(net,pin);
}

Notes:
  I assume a good compiler can optimize call to netPin.add(net,pin) as
efficient as pin.addNet(net) or addNetPin(net,pin)

  This approach requires user to type in a bit more details than a
good code generating pre-processor does, but the obvious advantages
are much greater.


--
 victor      holen@netcom.com