struct DVECTOR2
{
	// Controls that the parameter is a valid type
	template Accepts(T) { enum Accepts = is(T == DVECTOR2) || is(T == float) || is(T == D3DXVECTOR2) || is(T == POINT); }
	
	// Whether the parameter is a float or not
 	template isScalar(T) { enum isScalar = is(T == float); }
	
	// The Variables
	float x = 0f;
	float y = 0f;

	// Default Constructor
	this()(float x, float y)
	{
		this.x = x;
		this.y = y;
	}

	// Float Constructor
 	this()(float xy) { this(xy, xy); }

	// Implement D3DXVECTOR2 and POINT support
	this(T)(T arg) if(Accepts!T && !isScalar!T) { this(arg.tupleof); }

	// Inverse the vector
	DVECTOR2 opUnary(string op)() if(op == "-") { return DVECTOR2(-x, -y); }
	
	// Binary Operations
	DVECTOR2 opBinary(string op, T)(T rhs) if(Accepts!T)
	{
		enum rx = isScalar!T ? "" : ".x";
		enum ry = isScalar!T ? "" : ".y";
		
		return DVECTOR2(mixin("x" ~ op ~ "rhs" ~ rx), mixin("y" ~ op ~ "rhs" ~ ry));
	}
	
	// Right Binary Operator
	DVECTOR2 opBinaryRight(string op, T)(T lhs) if(Accepts!T) { return DVECTOR2(lhs).opBinary!op(this); }
	
	// Assign Operator
	ref DVECTOR2 opAssign(T)(T rhs) if(Accepts!T)
	{
		static if(isScalar!T)
			x = y = rhs;
			
		else
		{
			x = rhs.x;
			y = rhs.y;
		}
		
		return this;
	}
	
	// In-Place Assignment Operators
	ref DVECTOR2 opOpAssign(string op, T)(T rhs) if(Accepts!T) { return(this.opAssign(opBinary!op(rhs))); }

	// Cast Operators (to D3DXVECTOR2 and POINT)
	T opCast(T)() if(Accepts!T && !isScalar!T) { return T(x, y); }
}

unittest
{
	// This fails, saying that the expression cannot be
	// evaluated at compile time.
	immutable DVECTOR2 test = DVECTOR2(0f, 1f, 0f);
}