Implement modules as singletons Python semantics.
In Python, importing module several times returns same underlying module
object. This also fixes import statement handling for builtin modules.
There're still issues:
1. CPython exposes set of loaded modules as sys.modules, we may want to
do that either.
2. Builtin modules are implicitly imported, which is not really correct.
We should separate registering a (builtin) module and importing a module.
CPython keeps builtin module names in sys.builtin_module_names .
diff --git a/py/obj.h b/py/obj.h
index 510108e..11ec4af 100644
--- a/py/obj.h
+++ b/py/obj.h
@@ -356,6 +356,7 @@
// module
extern const mp_obj_type_t module_type;
mp_obj_t mp_obj_new_module(qstr module_name);
+mp_obj_t mp_obj_module_get(qstr module_name);
struct _mp_map_t *mp_obj_module_get_globals(mp_obj_t self_in);
// staticmethod and classmethod types; defined here so we can make const versions