Re: Dealing with property function and operator overloads

[Jacob Carlborg]

On 2011-10-03 20:57, Andrej Mitrovic wrote:

Looks like I can use some D tricks for this:

import std.stdio;

struct Point
{
     int x, y;

     void opOpAssign(string op)(int rhs)
     {
         mixin ("x = x " ~ op ~ " rhs;");
         mixin ("y = y " ~ op ~ " rhs;");
     }
}

struct Wrapped(T)
{
     T payload;
     alias payload this;
     void delegate() dg;

     @property void changed(void delegate() dg)
     {
         this.dg = dg;
     }

     void opOpAssign(string op)(int rhs)
     {
         payload.opOpAssign!op(rhs);
         dg();
     }
}

struct Wrapper
{
     this(int x)
     {
         point.changed =&notifyChanged;
     }

     void notifyChanged()
     {
         writeln("changed!");
     }

     public Wrapped!Point point;
}


void main()
{
     auto wrap = Wrapper(1);
     wrap.point = Point(1, 1);
     assert(wrap.point == Point(1, 1));

     wrap.point += 1;
     assert(wrap.point == Point(2, 2));
}

Pretty cool. I might even be able to write a Wrapped() template that
searches for all operator overloads of a type and creates forwarding
functions.

No "alias this" in the wrapper?

--
/Jacob Carlborg