Re: Dealing with property function and operator overloads

[Andrej Mitrovic]

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.