Factor out mp_seq_count_obj() and implement tuple.count().

py/obj.h

@@ -403,3 +403,4 @@ bool m_seq_get_fast_slice_indexes(machine_uint_t len, mp_obj_t slice, machine_ui
 bool mp_seq_cmp_bytes(int op, const byte *data1, uint len1, const byte *data2, uint len2);
 bool mp_seq_cmp_objs(int op, const mp_obj_t *items1, uint len1, const mp_obj_t *items2, uint len2);
 mp_obj_t mp_seq_index_obj(const mp_obj_t *items, uint len, uint n_args, const mp_obj_t *args);
+mp_obj_t mp_seq_count_obj(const mp_obj_t *items, uint len, mp_obj_t value);

py/objlist.c

@@ -260,14 +260,7 @@ static mp_obj_t list_copy(mp_obj_t self_in) {
 static mp_obj_t list_count(mp_obj_t self_in, mp_obj_t value) {
     assert(MP_OBJ_IS_TYPE(self_in, &list_type));
     mp_obj_list_t *self = self_in;
-    int count = 0;
-    for (int i = 0; i < self->len; i++) {
-         if (mp_obj_equal(self->items[i], value)) {
-              count++;
-         }
-    }
-
-    return mp_obj_new_int(count);
+    return mp_seq_count_obj(self->items, self->len, value);
 }
 
 static mp_obj_t list_index(uint n_args, const mp_obj_t *args) {

py/objtuple.c

@@ -153,6 +153,13 @@ static mp_obj_t tuple_getiter(mp_obj_t o_in) {
     return mp_obj_new_tuple_iterator(o_in, 0);
 }
 
+static mp_obj_t tuple_count(mp_obj_t self_in, mp_obj_t value) {
+    assert(MP_OBJ_IS_TYPE(self_in, &tuple_type));
+    mp_obj_tuple_t *self = self_in;
+    return mp_seq_count_obj(self->items, self->len, value);
+}
+static MP_DEFINE_CONST_FUN_OBJ_2(tuple_count_obj, tuple_count);
+
 static mp_obj_t tuple_index(uint n_args, const mp_obj_t *args) {
     assert(MP_OBJ_IS_TYPE(args[0], &tuple_type));
     mp_obj_tuple_t *self = args[0];
@@ -161,6 +168,7 @@ static mp_obj_t tuple_index(uint n_args, const mp_obj_t *args) {
 static MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(tuple_index_obj, 2, 4, tuple_index);
 
 static const mp_method_t tuple_type_methods[] = {
+    { "count", &tuple_count_obj },
     { "index", &tuple_index_obj },
     { NULL, NULL }, // end-of-list sentinel
 };

py/sequence.c

@@ -164,3 +164,15 @@ mp_obj_t mp_seq_index_obj(const mp_obj_t *items, uint len, uint n_args, const mp
 
     nlr_jump(mp_obj_new_exception_msg(MP_QSTR_ValueError, "object not in sequence"));
 }
+
+mp_obj_t mp_seq_count_obj(const mp_obj_t *items, uint len, mp_obj_t value) {
+    uint count = 0;
+    for (uint i = 0; i < len; i++) {
+         if (mp_obj_equal(items[i], value)) {
+              count++;
+         }
+    }
+
+    // Common sense says this cannot overflow small int
+    return MP_OBJ_NEW_SMALL_INT(count);
+}

tests/basics/tuple_count.py

+a = (1, 2, 3)
+a = a + a + a
+b = (0, 0, a, 0, a, 0)
+print(a.count(2))
+print(b.count(a))