/**
 *  payloads/cons.h
 *
 *  A cons cell.
 *
 *  (c) 2026 Simon Brooke <simon@journeyman.cc>
 *  Licensed under GPL version 2.0, or, at your option, any later version.
 */

#ifndef __psse_payloads_cons_h
#define __psse_payloads_cons_h
#include <stdbool.h>

#include "memory/node.h"
#include "memory/pointer.h"
#include "memory/pso2.h"
#include "memory/pso4.h"

#define CONS_SIZE_CLASS 2

/* NOTE THAT the definition of a cons payload has to be in memory/pso2.h to
 * avoid circularity. */

struct pso_pointer car( struct pso_pointer frame_pointer );

struct pso_pointer cdr( struct pso_pointer frame_pointer );

struct pso_pointer cons( struct pso_pointer frame_pointer );

struct pso_pointer destroy_cons( struct pso_pointer frame_pointer );

struct pso_pointer make_cons( struct pso_pointer frame_pointer,
                              struct pso_pointer car, struct pso_pointer cdr );

/**
 * macro short-cuts for make_cons.
 */
// #define make_cons(frame_pointer,car,cdr) (cons(make_frame(2, frame_pointer, car, cdr)))

/**
 * Variant which assumes a convention that the frame pointer will always be
 * called `frame_pointer`
 */
#define make_cons2(car,cdr) (cons(make_frame(2, frame_pointer, car, cdr)))

#define c_car(p)(sequencep(p) ? pointer_to_object(p)->payload.cons.car : nil)
#define c_cdr(p)(sequencep(p) ? pointer_to_object(p)->payload.cons.cdr : nil)

#endif