🚀 go-pugleaf

Why is it not allowed to delegate the initialisation to another 
constructor, if that constructor is *the only thing* in the 
member initialisation list? 

It seems to me that in many cases, one could avoid some code 
duplication and gain some clarity, at no conceptual or runtime cost.
The increased clarity would come from folding different constructor
cases into one case by calling the most general constructor in
the member initialisation list of the other constructors.
(I know this is not always clearer, but sometimes it is.)

Is it a case of: "Yes, it is basically a good idea, but it is too 
late in the standardisation process. Anyway, we have to draw the
line somewhere."

Or is it more like: "Of course you should not do it that way, look here..."


A small example to illustrate the technical (not the conceptual)
detatils of my question:

#include <iostream.h>

class X
{
public:
    X (int i) : i_(i) {}

    X () : X(34) {}		// Not allowed

    int i() {return i_;}

private:
    int i_;
};



int
main ()
{
    X a(55);
    X b;

    cout << a.i() << ' ' << b.i() << endl;
}
	

---
Jonas Mölsä, jbm@nada.kth.se

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