, scm_is_null, "empty list")

#define SCM_VALIDATE_NULL_OR_NIL(pos, scm) \
  SCM_MAKE_VALIDATE_MSG (pos, scm, NULL_OR_NIL_P, "empty list")

#define SCM_VALIDATE_CONS(pos, scm) \
  SCM_I_MAKE_VALIDATE_MSG2 (pos, scm, scm_is_pair, "pair")

#if (SCM_DEBUG_PAIR_ACCESSES == 1)
# define SCM_VALIDATE_PAIR(cell, expr) \
    ((!scm_is_pair (cell) ? scm_error_pair_access (cell), 0 : 0), (expr))
#else
# define SCM_VALIDATE_PAIR(cell, expr) (expr)
#endif

#ifdef BUILDING_LIBGUILE
#define SCM_VALIDATE_MUTABLE_PAIR(pos, scm) \
  SCM_I_MAKE_VALIDATE_MSG2 (pos, scm, scm_is_mutable_pair, "mutable pair")
#endif /* BUILDING_LIBGUILE */

#define SCM_VALIDATE_NULLORCONS(pos, env) \
  do { \
    SCM_ASSERT (scm_is_null (env) || scm_is_pair (env), env, pos, FUNC_NAME); \
  } while (0)