Kawa/gnu/mapping/HasSetter.java

package gnu.mapping;

/** A Procedure that can be used on the left-hand-side of an assignment.
  * It can do that by overriding getSetter.
  * Alternatively, it can use the default getSetter, as long as it
  * overrides one of set0 (if a 0-argument Procedure)
  * set1 (if a 1-argument Procedure), or setN (otherwise).
  */

public interface HasSetter
{
  public Procedure getSetter();
};

/*
(define-syntax set!
 (syntax-rules ()
  ((set! (func arg ...) rhs)
   ((setter func) arg ... rhs))
  ((set! var rhs)
   (%set! var rhs))))

Better code generation:

(apply (setter f) rhs args ...)
=> f.set(rhs args ...)
E.g.
(set (f) rhs) =>  [compile f].set0([compile rhs])
(set (f x) rhs) =>  [compile f].set1([compile x], [compile rhs])
(set (f x1 .. xn) rhs)
    => [compile f].setN([[compile x1], .. [compile xn], [compile rhs]])

Examples:
(setter car) == set-car!
(setter cdr) == set-cdr!
(setter caXXXr) == (lambda (rhs pair) (set-car! (cXXXr pair) rhs)) ???
(setter cdXXXr) == (lambda (rhs pair) (set-cdr! (cXXXr pair) rhs)) ???
(setter list-ref) ...

(ENV 'NAME) => value of NAME in ENV
(set! (ENV 'NAME) VAL) => set value of NAME in ENV to VAL

(CELL) => current value of CELL
(set! (CELL) VALUE) => set value of CELL to VALUE
*/