dynamic classes and duck typing

[Ary Borenszweig]

retard wrote:
> Tue, 01 Dec 2009 03:16:47 -0800, Walter Bright wrote:
> 
>> Ary Borenszweig wrote:
>>> Can you show examples of points 2, 3 and 4?
>> Have opDispatch look up the string in an associative array that returns
>> an associated delegate, then call the delegate.
>>
>> The dynamic part will be loading up the associative array at run time.
> 
> This is not exactly what everyone of us expected. I'd like to have 
> something like
> 
> void foo(Object o) {
>   o.duckMethod();
> }
> 
> foo(new Object() { void duckMethod() {} });
> 
> The feature isn't very dynamic since the dispatch rules are defined 
> statically. The only thing you can do is rewire the associative array 
> when forwarding statically precalculated dispatching.

Exactly! That's the kind of example I was looking for, thanks. Also:

class Foo {
   ... opDispatch ...
}

class Bar : Foo {
   // Let's make Bar understand more things...
   ... opDispatch ...
}

Foo foo = new Bar();
foo.something();

will not work as expected because something() will be bound to Foo's 
opDispatch and it isn't a virtual method. Of course you can make 
opDispatch invoke a virtual function and override that function in Bar, 
but since there isn't a standard name or method for doing this everyone 
will start doing it their way (I don't like it when there's no 
standarization for well-known operations) and it looks like a hack.