If I had my way

[Jonathan M Davis]

On Tuesday, December 13, 2011 05:13:29 F i L wrote:
> On Monday, 12 December 2011 at 21:57:36 UTC, Jonathan M Davis
> 
> wrote:
> > There has been discussion of UFCS (universal function call
> > syntax), which would then expand that beyond arrays to _all_
> > types - int, float, any user-
> > defined type, etc. However, there are a number of issues with
> > that (particularly with user-defined types; e.g. what if a
> > member function and a free function have the same name?), and
> > it has yet to be implemented. It may never be implemented.
> 
> C# easily avoids member confusion with pseudo methods by using
> the 'this' keyword as a parameter attribute in the pseudo method
> (http://msdn.microsoft.com/en-us/library/bb383977.aspx). Any
> function(this a, b) can be invoked as: a.function(b) in C#. I
> understand using the 'this' keyword as a parameter attribute
> already serves a different purpose in D, but I'm sure another
> keyword ('pseudo' perhaps?) or equivalent syntax could be
> reached. At which point, any external pseudo method conflicting
> with an objects internal members could simply result in a
> compiler error (or, member functions could take priority over
> pseudo methods).

There have been a variety of suggestions on how to do it - including one 
similar to what you're suggesting with the this keyword. However, it still 
leaves the problem of disambiguation that I mentioned. What happens when 
there's a free function and a member function with the same name and same 
parameters? Which one gets called? It's issues like that which are more of a 
problem than the exact syntax for declaring it IMHO. And all of those details 
need to be sorted out in a satisfactory manner before we can add UFCS to the 
language in any form.

For arrays, all you need to do is have the first argument be an array, and that 
works great for arrays, but arrays don't have much in the way of functions 
built in, so there's no conflict.

Realistically, at this point, I'd expect that if UFCS gets added any time 
soon, it's going to require that someone other than Walter do it and that they 
have do it very solidly, otherwise it could be a long time before it stands 
any chance of happening, simply because Walter is focused on fixing major bugs 
and stabilizing the compiler and isn't likely to look at adding new features 
anytime soon if there's no dire need (even if they're backwards compatible).

- Jonathan M Davis