Denis Koroskin wrote:
On Fri, 17 Apr 2009 18:24:04 +0400, Steven Schveighoffer <schvei...@yahoo.com> 
wrote:

On Fri, 17 Apr 2009 09:44:09 -0400, Leandro Lucarella <llu...@gmail.com> wrote:

I don't fully understand the example though. In writefln((v.qq = 5).i),
how is that B.i is assigned to 5 if the opDotExp("qq", 5) don't propagate
the 5 to the new B()?
I think it translates to

opDotExp("qq") = 5

Without knowing the signature of qq, how is the compiler supposed to infer that it is a property? In fact, I think this might be a limitation of this syntax, you can't define dynamic properties.

I for one, can't really see a huge benefit, but then again, I don't normally work with dynamic-type langauges. It looks to me like a huge hole that the compiler will ignore bugs that would have been caught if the methods were strongly typed:

class c
{
   void opDotExp(char[] methodname,...)
   {
      if(methodname == "mymethod")
         callMyMethod();
      else
         throw new Exception("bad method name: " ~ methodname);
   }
}

void foo(c myc, bool rarelySetToTrue)
{
   if(rarelySetToTrue)
     myc.mymethud(); // compiles, will throw runtime exception
}

Also, how do you overload the return value? Using this proposal, you can't have different dynamic methods that return different types.

-Steve

Here is how it could be done:

class C
{
    auto opDot(string methodName, T... args)(T args) // opDotExp renamed to 
opDot
    {
        static if (methodName == "length") {
            return _length; // return type is size_t
        } else static if (methodName == "resize") {
            _resize(args); // return type is void
        }
    }
}

This is a great use-case for compile-time "static switch". Can we haz one, 
please?

I think the more urgent need is for static loops. At least we have a simple workaround for static switch.

Andrei

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