On Fri, 03 Jul 2009 21:36:01 -0400, Mike L. <sgtmuff...@myrealbox.com>
wrote:
So currently if you want to overload just one case of an overloaded
function, you have to use an alias for the class to keep the behavior of
the other cases. I talked about it a little in #d, and the only reason
that was given was that it might protect the programmer somehow. But why
should the default behavior cause a sub-classto no longer behave like
the class that it extends? Not to sound like a Java fanboy (I'm not,
it's just the only other language I'm able try it out on right now), but
it doesn't require anything like that, and behaves how I would consider
intuitively. Isn't function overloading just re-using a name? Why is
that reason to treat things differently when they're inherited? Thanks.
It has to do with hijacking.
Read http://www.digitalmars.com/d/2.0/hijack.html
The pertinent part is in the sections entitled "Derived Class Member
Function Hijacking" and "Base Class Member Function Hijacking"
I argued your case, oh like 2 years ago, but Walter believes that
Hijacking is too much of a risk to allow overriding a single overload
without overriding all of them. In addition, the workaround to get the
desired behavior is pretty straightforward (the alias base.function
function syntax).
Note that C++ rules are the same as D's. I think in actuality, Walter
just implemented the C++ rules, and then came up with the hijacking
reasoning afterwards to explain why he did it ;) I have to admit, in
practice it doesn't come up very often unless you have certain designs.
For instance, I used C++ for many years, and never ran into this problem.
-Steve
