Implement __bool__ and __len__ via unary_op virtual method for all types.

__bool__() and __len__() are just the same as __neg__() or __invert__(),
and require efficient dispatching implementation (not requiring search/lookup).
type->unary_op() is just the right choice for this short of adding
standalone virtual method(s) to already big mp_obj_type_t structure.

1 files changed, 2 insertions, 1 deletions

diff --git a/py/objlist.c b/py/objlist.c
index fb68e2c566..81040e3b8e 100644
--- a/py/objlist.c
+++ b/py/objlist.c
@@ -125,7 +125,8 @@ static bool list_cmp_helper(int op, mp_obj_t self_in, mp_obj_t another_in) {
 static mp_obj_t list_unary_op(int op, mp_obj_t self_in) {
     mp_obj_list_t *self = self_in;
     switch (op) {
-        case RT_UNARY_OP_NOT: if (self->len == 0) { return mp_const_true; } else { return mp_const_false; }
+        case RT_UNARY_OP_BOOL: return MP_BOOL(self->len != 0);
+        case RT_UNARY_OP_LEN: return MP_OBJ_NEW_SMALL_INT(self->len);
         default: return MP_OBJ_NULL; // op not supported for None
     }
 }