D versus Objective C Comparison

[Michel Fortin]

On 2009-02-03 02:15:16 -0500, "Nick Sabalausky" <a at a.a> said:

> "Nick Sabalausky" <a at a.a> wrote in message
> news:gm8pul$1eei$1 at digitalmars.com...
>> I had been slowly coming around to the idea of having that universal
>> function syntax instead of C#-style explicit extension methods, but maybe
>> this need for dynamic dispatch is a good reason to prefer explicit
>> extension methods:
>> 
>> // As in C#, the "this" means backup() is an extension method
>> void backup(this Node obj, string backupPath)
>> {
>> // base impl
>> }
>> void backup(this File obj, string backupPath)
>> {
>> copy(obj.path, backupPath ~ "/" ~ obj.name);
>> }
>> void backup(this Directory obj, string backupPath)
>> {
>> foreach(child; children)
>> child.backup(backupPath ~ "/" ~ obj.name);
>> }
>> 
>> I'm not exactly sure what C# does in this case, but what I'm proposing
>> here is that this could (somehow) cause dynamic dispatch to be used.
> 
> Out of curiosity, I just did a little test on this in C#. Apperently it
> doesn't do any dynamic dispatch on this, it just calls the extension method
> overload for whatever the static type is.

Great. :-) An area where we could surpass C# by just making things work 
the way they should. Although I'm somewhat doubtful we'll see Walter 
going away from the simple C++-like vtable design needed for 
implementing this.

-- 
Michel Fortin
michel.fortin at michelf.com
http://michelf.com/