Ary Borenszweig wrote:
Ary Borenszweig wrote:
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.
Actuall, just the first part of the example:
void foo(Object o) {
o.duckMethod();
}
Can't do that because even if the real instance of Object has an
opDispatch method, it'll give a compile-time error because Object does
not defines duckMethod.
That's why this is something useful in scripting languages (or ruby,
python, etc.): if the method is not defined at runtime it's an error
unless you define the magic function that catches all. Can't do that in
D because the lookup is done at runtime.
Basically:
Dynanic d = ...;
d.something(1, 2, 3);
is just a shortcut for doing
d.opDispatch!("something")(1, 2, 3);
(and it's actually what the compiler does) but it's a standarized way of
doing that. What's the fun in that?
I take it back!
It would be very cool to have something like ruby's dynamic
attribute-based finders in D:
http://api.rubyonrails.org/classes/ActiveRecord/Base.html
