+
+ao_poly
+ao_scheme_do_car(struct ao_scheme_cons *cons)
+{
+ struct ao_scheme_cons *pair;
+
+ if (!ao_scheme_parse_args(_ao_scheme_atom_car, cons,
+ AO_SCHEME_CONS, &pair,
+ AO_SCHEME_ARG_END))
+ return AO_SCHEME_NIL;
+ return pair->car;
+}
+
+ao_poly
+ao_scheme_do_cdr(struct ao_scheme_cons *cons)
+{
+ struct ao_scheme_cons *pair;
+
+ if (!ao_scheme_parse_args(_ao_scheme_atom_cdr, cons,
+ AO_SCHEME_CONS, &pair,
+ AO_SCHEME_ARG_END))
+ return AO_SCHEME_NIL;
+ return pair->cdr;
+}
+
+ao_poly
+ao_scheme_do_cons(struct ao_scheme_cons *cons)
+{
+ ao_poly car, cdr;
+
+ if (!ao_scheme_parse_args(_ao_scheme_atom_cons, cons,
+ AO_SCHEME_POLY, &car,
+ AO_SCHEME_POLY, &cdr,
+ AO_SCHEME_ARG_END))
+ return AO_SCHEME_NIL;
+ return ao_scheme_cons(car, cdr);
+}
+
+ao_poly
+ao_scheme_do_last(struct ao_scheme_cons *cons)
+{
+ struct ao_scheme_cons *pair;
+
+ if (!ao_scheme_parse_args(_ao_scheme_atom_last, cons,
+ AO_SCHEME_CONS | AO_SCHEME_ARG_NIL_OK, &pair,
+ AO_SCHEME_ARG_END))
+ return AO_SCHEME_NIL;
+ while (pair) {
+ if (!pair->cdr)
+ return pair->car;
+ pair = ao_scheme_cons_cdr(pair);
+ }
+ return AO_SCHEME_NIL;
+}
+
+ao_poly
+ao_scheme_do_length(struct ao_scheme_cons *cons)
+{
+ struct ao_scheme_cons *pair;
+ if (!ao_scheme_parse_args(_ao_scheme_atom_length, cons,
+ AO_SCHEME_CONS | AO_SCHEME_ARG_NIL_OK, &pair,
+ AO_SCHEME_ARG_END))
+ return AO_SCHEME_NIL;
+ return ao_scheme_integer_poly(ao_scheme_cons_length(pair));
+}
+
+ao_poly
+ao_scheme_do_list_copy(struct ao_scheme_cons *cons)
+{
+ struct ao_scheme_cons *pair;
+
+ if (!ao_scheme_parse_args(_ao_scheme_atom_list2dcopy, cons,
+ AO_SCHEME_CONS | AO_SCHEME_ARG_NIL_OK, &pair,
+ AO_SCHEME_ARG_END))
+ return AO_SCHEME_NIL;
+ return ao_scheme_cons_poly(ao_scheme_cons_copy(pair));
+}
+
+ao_poly
+ao_scheme_do_list_tail(struct ao_scheme_cons *cons)
+{
+ ao_poly list;
+ int32_t v;
+
+ if (!ao_scheme_parse_args(_ao_scheme_atom_list2dtail, cons,
+ AO_SCHEME_CONS | AO_SCHEME_ARG_NIL_OK | AO_SCHEME_ARG_RET_POLY, &list,
+ AO_SCHEME_INT, &v,
+ AO_SCHEME_ARG_END))
+ return AO_SCHEME_NIL;
+
+ while (v > 0) {
+ if (!list)
+ return ao_scheme_error(AO_SCHEME_INVALID, "%v: ran off end", _ao_scheme_atom_list2dtail);
+ if (!ao_scheme_is_cons(list))
+ return ao_scheme_error(AO_SCHEME_INVALID, "%v: invalid list", _ao_scheme_atom_list2dtail);
+ list = ao_scheme_poly_cons(list)->cdr;
+ v--;
+ }
+ return list;
+}
+
+ao_poly
+ao_scheme_do_pairp(struct ao_scheme_cons *cons)
+{
+ ao_poly val;
+
+ if (!ao_scheme_parse_args(_ao_scheme_atom_pair3f, cons,
+ AO_SCHEME_POLY, &val,
+ AO_SCHEME_ARG_END))
+ return AO_SCHEME_NIL;
+ if (ao_scheme_is_pair(val))
+ return _ao_scheme_bool_true;
+ return _ao_scheme_bool_false;
+}
+
+/* This one is special -- a list is either nil or
+ * a 'proper' list with only cons cells
+ */
+ao_poly
+ao_scheme_do_listp(struct ao_scheme_cons *cons)
+{
+ ao_poly val;
+
+ if (!ao_scheme_parse_args(_ao_scheme_atom_pair3f, cons,
+ AO_SCHEME_POLY, &val,
+ AO_SCHEME_ARG_END))
+ return AO_SCHEME_NIL;
+ for (;;) {
+ if (val == AO_SCHEME_NIL)
+ return _ao_scheme_bool_true;
+ if (!ao_scheme_is_cons(val))
+ return _ao_scheme_bool_false;
+ val = ao_scheme_poly_cons(val)->cdr;
+ }
+}
+
+ao_poly
+ao_scheme_do_set_car(struct ao_scheme_cons *cons)
+{
+ struct ao_scheme_cons *pair;
+ ao_poly val;
+
+ if (!ao_scheme_parse_args(_ao_scheme_atom_set2dcar21, cons,
+ AO_SCHEME_CONS, &pair,
+ AO_SCHEME_POLY, &val,
+ AO_SCHEME_ARG_END))
+ return AO_SCHEME_NIL;
+ pair->car = val;
+ return val;
+}
+
+ao_poly
+ao_scheme_do_set_cdr(struct ao_scheme_cons *cons)
+{
+ struct ao_scheme_cons *pair;
+ ao_poly val;
+
+ if (!ao_scheme_parse_args(_ao_scheme_atom_set2dcar21, cons,
+ AO_SCHEME_CONS, &pair,
+ AO_SCHEME_POLY, &val,
+ AO_SCHEME_ARG_END))
+ return AO_SCHEME_NIL;
+ pair->cdr = val;
+ return val;
+}
+