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.
diff --git a/py/objbool.c b/py/objbool.c
index 53b2bf8..3a3ac3e 100644
--- a/py/objbool.c
+++ b/py/objbool.c
@@ -36,7 +36,7 @@
static mp_obj_t bool_unary_op(int op, mp_obj_t o_in) {
machine_int_t value = ((mp_obj_bool_t*)o_in)->value;
switch (op) {
- case RT_UNARY_OP_NOT: if (value) { return mp_const_false; } else { return mp_const_true; }
+ case RT_UNARY_OP_BOOL: return o_in;
case RT_UNARY_OP_POSITIVE: return MP_OBJ_NEW_SMALL_INT(value);
case RT_UNARY_OP_NEGATIVE: return MP_OBJ_NEW_SMALL_INT(-value);
case RT_UNARY_OP_INVERT: