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====== It seems like many implementations are using Abstract Syntax Tree rewriting to enable DCI. How does it work? ======
[[http://en.wikipedia.org/wiki/Abstract_syntax_tree|AST]] rewriting can emulate the [[http://folk.uio.no/trygver/2012/DCIExecutionModel-2.1.pdf|DCI execution model]] by rewriting the RoleMethods and the calls to them as private class methods in the Context class.

Some pseudocode:
<code javascript>
Context OKCorrallShowdown {
     role Shape {
          void move(Point) {
          }
          void draw() {
          }
     };

     role Cowboy {
          void move(Point) {
          }
          void draw() {
          }
          void shoot() {
          }
     };

     void LightsCameraActionSystemOperation(Person x) {
	Cowboy <- x;	// inject the roles
	Shape <- x;

	Cowboy.move(Point(3,4));
	Shape.draw();	// a frame of the animation
	Cowboy.draw();
	Cowboy.shoot();
	Shape.draw();	// a frame of the animation
     }
};
</code>

There is nothing ambiguous about the above code: there is enough information to be able to call the right methods, so it can be implemented (by the compiler) using static name mangling:

<code javascript>
class OKCorrallShowdown {
     private Person Shape;

     private void Shape_move(Point) {
     }
     
     private void Shape_draw() {
     }

     private Person Cowboy;

     private void Cowboy_move(Point) {
     }
     
     private void Cowboy_draw() {
     }
     
     private void Cowboy_shoot() {
     }

     public void LightsCameraActionSystemOperation(Person x) {
	Cowboy = x;
	Shape = x;

	Cowboy_move(Point(3,4));
	Shape_draw();
	Cowboy_draw();
	Cowboy_shoot();
	Shape_draw();
     }
};
</code>

This approach is completely unambiguous, even if an object has been injected with a role from a different Context (somewhere up the Context stack).
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