+#define SYMBOL_SELF(sym) (scm_c_vector_ref (sym, 0))
+#define SET_SYMBOL_SELF(sym, v) (scm_c_vector_set_x (sym, 0, v))
+#define SYMBOL_REDIRECT(sym) (XINT (scm_c_vector_ref (sym, 1)))
+#define SET_SYMBOL_REDIRECT(sym, v) (scm_c_vector_set_x (sym, 1, make_number (v)))
+#define SYMBOL_CONSTANT(sym) (XINT (scm_c_vector_ref (sym, 2)))
+#define SET_SYMBOL_CONSTANT(sym, v) (scm_c_vector_set_x (sym, 2, make_number (v)))
+#define SYMBOL_DECLARED_SPECIAL(sym) (XINT (scm_c_vector_ref (sym, 3)))
+#define SET_SYMBOL_DECLARED_SPECIAL(sym, v) (scm_c_vector_set_x (sym, 3, make_number (v)))