Improved type/class/instance code; mp_obj_type_t now has load_attr, store_attr.

Creating of classes (types) and instances is much more like CPython now.
You can use "type('name', (), {...})" to create classes.

13 files changed, 288 insertions, 292 deletions

diff --git a/py/builtin.c b/py/builtin.c
index 5dbf47ab84..50e9c02df5 100644
--- a/py/builtin.c
+++ b/py/builtin.c
@@ -23,8 +23,8 @@ mp_obj_t mp_builtin___build_class__(int n_args, const mp_obj_t *args) {
 
     // we differ from CPython: we set the new __locals__ object here
     mp_map_t *old_locals = rt_locals_get();
-    mp_map_t *class_locals = mp_map_new(0);
-    rt_locals_set(class_locals);
+    mp_obj_t class_locals = mp_obj_new_dict(0);
+    rt_locals_set(mp_obj_dict_get_map(class_locals));
 
     // call the class code
     mp_obj_t cell = rt_call_function_1(args[0], (mp_obj_t)0xdeadbeef);
@@ -32,7 +32,6 @@ mp_obj_t mp_builtin___build_class__(int n_args, const mp_obj_t *args) {
     // restore old __locals__ object
     rt_locals_set(old_locals);
 
-    /*
     // get the class type (meta object) from the base objects
     mp_obj_t meta;
     if (n_args == 2) {
@@ -42,21 +41,16 @@ mp_obj_t mp_builtin___build_class__(int n_args, const mp_obj_t *args) {
         // use type of first base object
         meta = mp_obj_get_type(args[2]);
     }
-    */
 
     // TODO do proper metaclass resolution for multiple base objects
 
-    /*
     // create the new class using a call to the meta object
     // (arguments must be backwards in the array)
     mp_obj_t meta_args[3];
     meta_args[2] = args[1]; // class name
     meta_args[1] = mp_obj_new_tuple(n_args - 2, args + 2); // tuple of bases
-    meta_args[0] = class_locals; // dict of members TODO, currently is a map
+    meta_args[0] = class_locals; // dict of members
     mp_obj_t new_class = rt_call_function_n(meta, 3, meta_args);
-    */
-    // create the new class
-    mp_obj_t new_class = mp_obj_new_class(class_locals);
 
     // store into cell if neede
     if (cell != mp_const_none) {
diff --git a/py/map.h b/py/map.h
index 4905f5bc18..5ce4e835b6 100644
--- a/py/map.h
+++ b/py/map.h
@@ -18,7 +18,7 @@ typedef struct _mp_set_t {
     mp_obj_t *table;
 } mp_set_t;
 
-typedef enum {
+typedef enum _mp_map_lookup_kind_t {
     MP_MAP_LOOKUP,
     MP_MAP_LOOKUP_ADD_IF_NOT_FOUND,
     MP_MAP_LOOKUP_REMOVE_IF_FOUND,
diff --git a/py/obj.h b/py/obj.h
index 5eb9fee75a..8643dbb91b 100644
--- a/py/obj.h
+++ b/py/obj.h
@@ -61,6 +61,8 @@ typedef struct _mp_obj_base_t mp_obj_base_t;
 
 // Need to declare this here so we are not dependent on map.h
 struct _mp_map_t;
+struct _mp_map_elem_t;
+enum _mp_map_lookup_kind_t;
 
 // Type definitions for methods
 
@@ -78,6 +80,8 @@ typedef mp_obj_t (*mp_call_n_fun_t)(mp_obj_t fun, int n_args, const mp_obj_t *ar
 typedef mp_obj_t (*mp_call_n_kw_fun_t)(mp_obj_t fun, int n_args, int n_kw, const mp_obj_t *args); // args are in reverse order in the array
 typedef mp_obj_t (*mp_unary_op_fun_t)(int op, mp_obj_t);
 typedef mp_obj_t (*mp_binary_op_fun_t)(int op, mp_obj_t, mp_obj_t);
+typedef void (*mp_load_attr_fun_t)(mp_obj_t self_in, qstr attr, mp_obj_t *dest); // for fail, do nothing; for attr, dest[1] = value; for method, dest[0] = self, dest[1] = method
+typedef bool (*mp_store_attr_fun_t)(mp_obj_t self_in, qstr attr, mp_obj_t value); // return true if store succeeded
 
 typedef struct _mp_method_t {
     const char *name;
@@ -141,15 +145,14 @@ struct _mp_obj_type_t {
 
     const mp_method_t *methods;
 
+    mp_load_attr_fun_t load_attr;
+    mp_store_attr_fun_t store_attr;
+    mp_obj_t locals;
+
     /*
     What we might need to add here:
 
-    dynamic_type    instance
-
     compare_op
-    load_attr       module instance class list
-    load_method     instance str gen list user
-    store_attr      module instance class
     store_subscr    list dict
 
     len             str tuple list map
@@ -160,7 +163,6 @@ struct _mp_obj_type_t {
     get_array_n     tuple list
 
     unpack seq      list tuple
-    __next__        gen-instance
     */
 };
 
@@ -178,6 +180,7 @@ extern const mp_obj_t mp_const_stop_iteration; // special object indicating end
 
 // General API for objects
 
+mp_obj_t mp_obj_new_type(qstr name, mp_obj_t local_dict);
 mp_obj_t mp_obj_new_none(void);
 mp_obj_t mp_obj_new_bool(bool value);
 mp_obj_t mp_obj_new_cell(mp_obj_t obj);
@@ -207,8 +210,6 @@ mp_obj_t mp_obj_new_dict(int n_args);
 mp_obj_t mp_obj_new_set(int n_args, mp_obj_t *items);
 mp_obj_t mp_obj_new_slice(mp_obj_t start, mp_obj_t stop, mp_obj_t step);
 mp_obj_t mp_obj_new_bound_meth(mp_obj_t self, mp_obj_t meth);
-mp_obj_t mp_obj_new_class(struct _mp_map_t *class_locals);
-mp_obj_t mp_obj_new_instance(mp_obj_t clas);
 mp_obj_t mp_obj_new_module(qstr module_name);
 
 mp_obj_t mp_obj_get_type(mp_obj_t o_in);
@@ -278,6 +279,7 @@ void mp_obj_list_store(mp_obj_t self_in, mp_obj_t index, mp_obj_t value);
 extern const mp_obj_type_t dict_type;
 uint mp_obj_dict_len(mp_obj_t self_in);
 mp_obj_t mp_obj_dict_store(mp_obj_t self_in, mp_obj_t key, mp_obj_t value);
+struct _mp_map_t *mp_obj_dict_get_map(mp_obj_t self_in);
 
 // set
 extern const mp_obj_type_t set_type;
@@ -307,15 +309,7 @@ void mp_obj_fun_bc_get(mp_obj_t self_in, int *n_args, uint *n_state, const byte
 extern const mp_obj_type_t gen_instance_type;
 
 // class
-extern const mp_obj_type_t class_type;
-extern const mp_obj_t gen_instance_next_obj;
-struct _mp_map_t *mp_obj_class_get_locals(mp_obj_t self_in);
-
-// instance
-extern const mp_obj_type_t instance_type;
-mp_obj_t mp_obj_instance_load_attr(mp_obj_t self_in, qstr attr);
-void mp_obj_instance_load_method(mp_obj_t self_in, qstr attr, mp_obj_t *dest);
-void mp_obj_instance_store_attr(mp_obj_t self_in, qstr attr, mp_obj_t value);
+struct _mp_map_elem_t *mp_obj_class_lookup(mp_obj_t self_in, qstr attr, enum _mp_map_lookup_kind_t lookup_kind);
 
 // module
 extern const mp_obj_type_t module_type;
diff --git a/py/objclass.c b/py/objclass.c
deleted file mode 100644
index 3ecce54739..0000000000
--- a/py/objclass.c
+++ /dev/null
@@ -1,74 +0,0 @@
-#include <stdlib.h>
-#include <stdint.h>
-#include <string.h>
-#include <assert.h>
-
-#include "nlr.h"
-#include "misc.h"
-#include "mpconfig.h"
-#include "mpqstr.h"
-#include "obj.h"
-#include "runtime.h"
-#include "map.h"
-
-typedef struct _mp_obj_class_t {
-    mp_obj_base_t base;
-    mp_map_t *locals;
-} mp_obj_class_t;
-
-// args are in reverse order in the array
-mp_obj_t class_call_n(mp_obj_t self_in, int n_args, const mp_obj_t *args) {
-    // instantiate an instance of a class
-
-    mp_obj_class_t *self = self_in;
-
-    // make instance
-    mp_obj_t o = mp_obj_new_instance(self_in);
-
-    // look for __init__ function
-    mp_map_elem_t *init_fn = mp_map_lookup(self->locals, MP_OBJ_NEW_QSTR(MP_QSTR___init__), MP_MAP_LOOKUP);
-
-    if (init_fn != NULL) {
-        // call __init__ function
-        mp_obj_t init_ret;
-        if (n_args == 0) {
-            init_ret = rt_call_function_n(init_fn->value, 1, (mp_obj_t*)&o);
-        } else {
-            mp_obj_t *args2 = m_new(mp_obj_t, n_args + 1);
-            memcpy(args2, args, n_args * sizeof(mp_obj_t));
-            args2[n_args] = o;
-            init_ret = rt_call_function_n(init_fn->value, n_args + 1, args2);
-            m_del(mp_obj_t, args2, n_args + 1);
-        }
-        if (init_ret != mp_const_none) {
-            nlr_jump(mp_obj_new_exception_msg_1_arg(MP_QSTR_TypeError, "__init__() should return None, not '%s'", mp_obj_get_type_str(init_ret)));
-        }
-
-    } else {
-        // TODO
-        if (n_args != 0) {
-            nlr_jump(mp_obj_new_exception_msg_1_arg(MP_QSTR_TypeError, "function takes 0 positional arguments but %d were given", (void*)(machine_int_t)n_args));
-        }
-    }
-
-    return o;
-}
-
-mp_map_t *mp_obj_class_get_locals(mp_obj_t self_in) {
-    assert(MP_OBJ_IS_TYPE(self_in, &class_type));
-    mp_obj_class_t *self = self_in;
-    return self->locals;
-}
-
-const mp_obj_type_t class_type = {
-    { &mp_const_type },
-    "class",
-    .call_n = class_call_n,
-};
-
-mp_obj_t mp_obj_new_class(mp_map_t *class_locals) {
-    mp_obj_class_t *o = m_new_obj(mp_obj_class_t);
-    o->base.type = &class_type;
-    o->locals = class_locals;
-    return o;
-}
diff --git a/py/objdict.c b/py/objdict.c
index 20e3e570d5..1c90998585 100644
--- a/py/objdict.c
+++ b/py/objdict.c
@@ -287,3 +287,9 @@ mp_obj_t mp_obj_dict_store(mp_obj_t self_in, mp_obj_t key, mp_obj_t value) {
     mp_map_lookup(&self->map, key, MP_MAP_LOOKUP_ADD_IF_NOT_FOUND)->value = value;
     return self_in;
 }
+
+mp_map_t *mp_obj_dict_get_map(mp_obj_t self_in) {
+    assert(MP_OBJ_IS_TYPE(self_in, &dict_type));
+    mp_obj_dict_t *self = self_in;
+    return &self->map;
+}
diff --git a/py/objinstance.c b/py/objinstance.c
deleted file mode 100644
index 9bb9acbd72..0000000000
--- a/py/objinstance.c
+++ /dev/null
@@ -1,103 +0,0 @@
-#include <stdlib.h>
-#include <stdint.h>
-#include <string.h>
-#include <assert.h>
-
-#include "nlr.h"
-#include "misc.h"
-#include "mpconfig.h"
-#include "mpqstr.h"
-#include "obj.h"
-#include "runtime.h"
-#include "map.h"
-
-typedef struct _mp_obj_instance_t {
-    mp_obj_base_t base;
-    mp_obj_base_t *class; // points to a "class" object
-    mp_map_t *members;
-} mp_obj_instance_t;
-
-/*
-type needs to be specified dynamically
-            case O_OBJ:
-            {
-                py_map_elem_t *qn = py_qstr_map_lookup(o->u_obj.class->u_class.locals, qstr_from_str_static("__qualname__"), false); assert(qn != NULL);
-                assert(IS_O(qn->value, O_STR));
-                return qstr_str(((py_obj_base_t*)qn->value)->u_str);
-            }
-            */
-
-mp_obj_t mp_obj_instance_load_attr(mp_obj_t self_in, qstr attr) {
-    // logic: look in obj members then class locals (TODO check this against CPython)
-    mp_obj_instance_t *self = self_in;
-    mp_map_elem_t *elem = mp_map_lookup(self->members, MP_OBJ_NEW_QSTR(attr), MP_MAP_LOOKUP);
-    if (elem != NULL) {
-        // object member, always treated as a value
-        return elem->value;
-    }
-    elem = mp_map_lookup(mp_obj_class_get_locals(self->class), MP_OBJ_NEW_QSTR(attr), MP_MAP_LOOKUP);
-    if (elem != NULL) {
-        if (mp_obj_is_callable(elem->value)) {
-            // class member is callable so build a bound method
-            return mp_obj_new_bound_meth(self_in, elem->value);
-        } else {
-            // class member is a value, so just return that value
-            return elem->value;
-        }
-    }
-    nlr_jump(mp_obj_new_exception_msg_2_args(MP_QSTR_AttributeError, "'%s' object has no attribute '%s'", mp_obj_get_type_str(self_in), qstr_str(attr)));
-}
-
-void mp_obj_instance_load_method(mp_obj_t self_in, qstr attr, mp_obj_t *dest) {
-    // logic: look in obj members then class locals (TODO check this against CPython)
-    mp_obj_instance_t *self = self_in;
-    mp_map_elem_t *elem = mp_map_lookup(self->members, MP_OBJ_NEW_QSTR(attr), MP_MAP_LOOKUP);
-    if (elem != NULL) {
-        // object member, always treated as a value
-        dest[1] = elem->value;
-        dest[0] = NULL;
-        return;
-    }
-    elem = mp_map_lookup(mp_obj_class_get_locals(self->class), MP_OBJ_NEW_QSTR(attr), MP_MAP_LOOKUP);
-    if (elem != NULL) {
-        if (mp_obj_is_callable(elem->value)) {
-            // class member is callable so build a bound method
-            dest[1] = elem->value;
-            dest[0] = self_in;
-            return;
-        } else {
-            // class member is a value, so just return that value
-            dest[1] = elem->value;
-            dest[0] = NULL;
-            return;
-        }
-    }
-
-    // no such method, so fall back to load attr
-    dest[1] = rt_load_attr(self_in, attr);
-    dest[0] = NULL;
-}
-
-void mp_obj_instance_store_attr(mp_obj_t self_in, qstr attr, mp_obj_t value) {
-    // logic: look in class locals (no add) then obj members (add) (TODO check this against CPython)
-    mp_obj_instance_t *self = self_in;
-    mp_map_elem_t *elem = mp_map_lookup(mp_obj_class_get_locals(self->class), MP_OBJ_NEW_QSTR(attr), MP_MAP_LOOKUP);
-    if (elem != NULL) {
-        elem->value = value;
-    } else {
-        mp_map_lookup(self->members, MP_OBJ_NEW_QSTR(attr), MP_MAP_LOOKUP_ADD_IF_NOT_FOUND)->value = value;
-    }
-}
-
-const mp_obj_type_t instance_type = {
-    { &mp_const_type },
-    "instance",
-};
-
-mp_obj_t mp_obj_new_instance(mp_obj_t class) {
-    mp_obj_instance_t *o = m_new_obj(mp_obj_instance_t);
-    o->base.type = &instance_type;
-    o->class = class;
-    o->members = mp_map_new(0);
-    return o;
-}
diff --git a/py/objmodule.c b/py/objmodule.c
index a5183b51e3..ade9369176 100644
--- a/py/objmodule.c
+++ b/py/objmodule.c
@@ -17,15 +17,32 @@ typedef struct _mp_obj_module_t {
     mp_map_t *globals;
 } mp_obj_module_t;
 
-void module_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t self_in) {
+static void module_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t self_in) {
     mp_obj_module_t *self = self_in;
     print(env, "<module '%s' from '-unknown-file-'>", qstr_str(self->name));
 }
 
+static void module_load_attr(mp_obj_t self_in, qstr attr, mp_obj_t *dest) {
+    mp_obj_module_t *self = self_in;
+    mp_map_elem_t *elem = mp_map_lookup(self->globals, MP_OBJ_NEW_QSTR(attr), MP_MAP_LOOKUP);
+    if (elem != NULL) {
+        dest[1] = elem->value;
+    }
+}
+
+static bool module_store_attr(mp_obj_t self_in, qstr attr, mp_obj_t value) {
+    mp_obj_module_t *self = self_in;
+    // TODO CPython allows STORE_ATTR to a module, but is this the correct implementation?
+    mp_map_lookup(self->globals, MP_OBJ_NEW_QSTR(attr), MP_MAP_LOOKUP_ADD_IF_NOT_FOUND)->value = value;
+    return true;
+}
+
 const mp_obj_type_t module_type = {
     { &mp_const_type },
     "module",
     .print = module_print,
+    .load_attr = module_load_attr,
+    .store_attr = module_store_attr,
 };
 
 mp_obj_t mp_obj_new_module(qstr module_name) {
diff --git a/py/objtype.c b/py/objtype.c
index 4a6025a70b..58854ca98d 100644
--- a/py/objtype.c
+++ b/py/objtype.c
@@ -1,11 +1,123 @@
 #include <stdlib.h>
 #include <stdint.h>
+#include <string.h>
+#include <assert.h>
 
 #include "nlr.h"
 #include "misc.h"
 #include "mpconfig.h"
 #include "mpqstr.h"
 #include "obj.h"
+#include "map.h"
+#include "runtime.h"
+
+/******************************************************************************/
+// class object
+// creating an instance of a class makes one of these objects
+
+typedef struct _mp_obj_class_t {
+    mp_obj_base_t base;
+    mp_map_t members;
+} mp_obj_class_t;
+
+static mp_obj_t mp_obj_new_class(mp_obj_t class) {
+    mp_obj_class_t *o = m_new_obj(mp_obj_class_t);
+    o->base.type = class;
+    mp_map_init(&o->members, 0);
+    return o;
+}
+
+static void class_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t self_in) {
+    print(env, "<%s object at %p>", mp_obj_get_type_str(self_in), self_in);
+}
+
+// args are reverse in the array
+static mp_obj_t class_make_new(mp_obj_t self_in, int n_args, const mp_obj_t *args) {
+    assert(MP_OBJ_IS_TYPE(self_in, &mp_const_type));
+
+    mp_obj_t o = mp_obj_new_class(self_in);
+
+    // look for __init__ function
+    mp_map_elem_t *init_fn = mp_obj_class_lookup(self_in, MP_QSTR___init__, MP_MAP_LOOKUP);
+
+    if (init_fn != NULL) {
+        // call __init__ function
+        mp_obj_t init_ret;
+        if (n_args == 0) {
+            init_ret = rt_call_function_n(init_fn->value, 1, (mp_obj_t*)&o);
+        } else {
+            mp_obj_t *args2 = m_new(mp_obj_t, n_args + 1);
+            memcpy(args2, args, n_args * sizeof(mp_obj_t));
+            args2[n_args] = o;
+            init_ret = rt_call_function_n(init_fn->value, n_args + 1, args2);
+            m_del(mp_obj_t, args2, n_args + 1);
+        }
+        if (init_ret != mp_const_none) {
+            nlr_jump(mp_obj_new_exception_msg_1_arg(MP_QSTR_TypeError, "__init__() should return None, not '%s'", mp_obj_get_type_str(init_ret)));
+        }
+
+    } else {
+        // TODO
+        if (n_args != 0) {
+            nlr_jump(mp_obj_new_exception_msg_1_arg(MP_QSTR_TypeError, "function takes 0 positional arguments but %d were given", (void*)(machine_int_t)n_args));
+        }
+    }
+
+    return o;
+}
+
+static void class_load_attr(mp_obj_t self_in, qstr attr, mp_obj_t *dest) {
+    // logic: look in obj members then class locals (TODO check this against CPython)
+    mp_obj_class_t *self = self_in;
+    mp_map_elem_t *elem = mp_map_lookup(&self->members, MP_OBJ_NEW_QSTR(attr), MP_MAP_LOOKUP);
+    if (elem != NULL) {
+        // object member, always treated as a value
+        dest[1] = elem->value;
+        return;
+    }
+    elem = mp_obj_class_lookup((mp_obj_t)self->base.type, attr, MP_MAP_LOOKUP);
+    if (elem != NULL) {
+        if (mp_obj_is_callable(elem->value)) {
+            // class member is callable so build a bound method
+            dest[1] = elem->value;
+            dest[0] = self_in;
+            return;
+        } else {
+            // class member is a value, so just return that value
+            dest[1] = elem->value;
+            return;
+        }
+    }
+}
+
+static bool class_store_attr(mp_obj_t self_in, qstr attr, mp_obj_t value) {
+    // logic: look in class locals (no add) then obj members (add) (TODO check this against CPython)
+    mp_obj_class_t *self = self_in;
+    mp_map_elem_t *elem = mp_obj_class_lookup((mp_obj_t)self->base.type, attr, MP_MAP_LOOKUP);
+    if (elem != NULL) {
+        elem->value = value;
+    } else {
+        mp_map_lookup(&self->members, MP_OBJ_NEW_QSTR(attr), MP_MAP_LOOKUP_ADD_IF_NOT_FOUND)->value = value;
+    }
+    return true;
+}
+
+mp_map_elem_t *mp_obj_class_lookup(mp_obj_t self_in, qstr attr, mp_map_lookup_kind_t lookup_kind) {
+    assert(MP_OBJ_IS_TYPE(self_in, &mp_const_type));
+    mp_obj_type_t *self = self_in;
+    if (self->locals == NULL) {
+        return NULL;
+    }
+    assert(MP_OBJ_IS_TYPE(self->locals, &dict_type)); // Micro Python restriction, for now
+    mp_map_t *locals_map = ((void*)self->locals + sizeof(mp_obj_base_t)); // XXX hack to get map object from dict object
+    return mp_map_lookup(locals_map, MP_OBJ_NEW_QSTR(attr), lookup_kind);
+}
+
+/******************************************************************************/
+// type object
+//  - the struct is mp_obj_type_t and is defined in obj.h so const types can be made
+//  - there is a constant mp_obj_type_t (called mp_const_type) for the 'type' object
+//  - creating a new class (a new type) creates a new mp_obj_type_t
 
 static void type_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t self_in) {
     mp_obj_type_t *self = self_in;
@@ -24,13 +136,7 @@ static mp_obj_t type_make_new(mp_obj_t type_in, int n_args, const mp_obj_t *args
             // args[1] = bases tuple
             // args[0] = locals dict
 
-            mp_obj_type_t *new_type = m_new0(mp_obj_type_t, 1);
-            new_type->base.type = &mp_const_type;
-            new_type->name = qstr_str(mp_obj_get_qstr(args[2]));
-            return new_type;
-
-            //mp_obj_t new_class = mp_obj_new_class(mp_obj_get_qstr(args[2]), args[0]);
-            //return new_class;
+            return mp_obj_new_type(mp_obj_get_qstr(args[2]), args[0]);
         }
 
         default:
@@ -38,14 +144,42 @@ static mp_obj_t type_make_new(mp_obj_t type_in, int n_args, const mp_obj_t *args
     }
 }
 
+// args are in reverse order in the array
 static mp_obj_t type_call_n(mp_obj_t self_in, int n_args, const mp_obj_t *args) {
+    // instantiate an instance of a class
+
     mp_obj_type_t *self = self_in;
-    if (self->make_new != NULL) {
-        // TODO we need to init the object if it's an instance of a type
-        return self->make_new(self, n_args, args);
-    } else {
+
+    if (self->make_new == NULL) {
         nlr_jump(mp_obj_new_exception_msg_1_arg(MP_QSTR_TypeError, "cannot create '%s' instances", self->name));
     }
+
+    // make new instance
+    mp_obj_t o = self->make_new(self, n_args, args);
+
+    // return new instance
+    return o;
+}
+
+// for fail, do nothing; for attr, dest[1] = value; for method, dest[0] = self, dest[1] = method
+static void type_load_attr(mp_obj_t self_in, qstr attr, mp_obj_t *dest) {
+    mp_map_elem_t *elem = mp_obj_class_lookup(self_in, attr, MP_MAP_LOOKUP);
+    if (elem != NULL) {
+        dest[1] = elem->value;
+        return;
+    }
+}
+
+static bool type_store_attr(mp_obj_t self_in, qstr attr, mp_obj_t value) {
+    // TODO CPython allows STORE_ATTR to a class, but is this the correct implementation?
+
+    mp_map_elem_t *elem = mp_obj_class_lookup(self_in, attr, MP_MAP_LOOKUP_ADD_IF_NOT_FOUND);
+    if (elem != NULL) {
+        elem->value = value;
+        return true;
+    } else {
+        return false;
+    }
 }
 
 const mp_obj_type_t mp_const_type = {
@@ -54,4 +188,19 @@ const mp_obj_type_t mp_const_type = {
     .print = type_print,
     .make_new = type_make_new,
     .call_n = type_call_n,
+    .load_attr = type_load_attr,
+    .store_attr = type_store_attr,
 };
+
+mp_obj_t mp_obj_new_type(qstr name, mp_obj_t local_dict) {
+    mp_obj_type_t *o = m_new0(mp_obj_type_t, 1);
+    o->base.type = &mp_const_type;
+    o->name = qstr_str(name);
+    o->print = class_print;
+    o->make_new = class_make_new;
+    o->load_attr = class_load_attr;
+    o->store_attr = class_store_attr;
+    o->locals = local_dict;
+    assert(MP_OBJ_IS_TYPE(o->locals, &dict_type)); // Micro Python restriction, for now
+    return o;
+}
diff --git a/py/py.mk b/py/py.mk
index c6c4e97058..a44a8bad02 100644
--- a/py/py.mk
+++ b/py/py.mk
@@ -74,7 +74,6 @@ PY_O_BASENAME = \
 	objbool.o \
 	objboundmeth.o \
 	objcell.o \
-	objclass.o \
 	objclosure.o \
 	objcomplex.o \
 	objdict.o \
@@ -82,7 +81,6 @@ PY_O_BASENAME = \
 	objfloat.o \
 	objfun.o \
 	objgenerator.o \
-	objinstance.o \
 	objint.o \
 	objlist.o \
 	objmodule.o \
diff --git a/py/runtime.c b/py/runtime.c
index 3c92ca68cb..2c3ff803bc 100644
--- a/py/runtime.c
+++ b/py/runtime.c
@@ -188,8 +188,10 @@ void rt_assign_byte_code(int unique_code_id, byte *code, uint len, int n_args, i
         DEBUG_printf(" %02x", code[i]);
     }
     DEBUG_printf("\n");
+#if MICROPY_SHOW_BC
     extern void mp_show_byte_code(const byte *code, int len);
     mp_show_byte_code(code, len);
+#endif
 
 #ifdef WRITE_CODE
     if (fp_write_code != NULL) {
@@ -775,85 +777,74 @@ mp_obj_t rt_store_map(mp_obj_t map, mp_obj_t key, mp_obj_t value) {
 }
 
 mp_obj_t rt_load_attr(mp_obj_t base, qstr attr) {
-    DEBUG_OP_printf("load attr %s\n", qstr_str(attr));
-    if (MP_OBJ_IS_TYPE(base, &class_type)) {
-        mp_map_elem_t *elem = mp_map_lookup(mp_obj_class_get_locals(base), MP_OBJ_NEW_QSTR(attr), MP_MAP_LOOKUP);
-        if (elem == NULL) {
-            // TODO what about generic method lookup?
-            goto no_attr;
-        }
-        return elem->value;
-    } else if (MP_OBJ_IS_TYPE(base, &instance_type)) {
-        return mp_obj_instance_load_attr(base, attr);
-    } else if (MP_OBJ_IS_TYPE(base, &module_type)) {
-        DEBUG_OP_printf("lookup module map %p\n", mp_obj_module_get_globals(base));
-        mp_map_elem_t *elem = mp_map_lookup(mp_obj_module_get_globals(base), MP_OBJ_NEW_QSTR(attr), MP_MAP_LOOKUP);
-        if (elem == NULL) {
-            // TODO what about generic method lookup?
-            goto no_attr;
-        }
-        return elem->value;
-    } else if (MP_OBJ_IS_OBJ(base)) {
-        // generic method lookup
-        mp_obj_base_t *o = base;
-        const mp_method_t *meth = o->type->methods;
-        if (meth != NULL) {
-            for (; meth->name != NULL; meth++) {
-                if (strcmp(meth->name, qstr_str(attr)) == 0) {
-                    return mp_obj_new_bound_meth(base, (mp_obj_t)meth->fun);
-                }
-            }
-        }
+    DEBUG_OP_printf("load attr %p.%s\n", base, qstr_str(attr));
+    // use load_method
+    mp_obj_t dest[2];
+    rt_load_method(base, attr, dest);
+    if (dest[0] == NULL) {
+        // load_method returned just a normal attribute
+        return dest[1];
+    } else {
+        // load_method returned a method, so build a bound method object
+        return mp_obj_new_bound_meth(dest[0], dest[1]);
     }
-
-no_attr:
-    nlr_jump(mp_obj_new_exception_msg_varg(MP_QSTR_AttributeError, "'%s' object has no attribute '%s'", mp_obj_get_type_str(base), qstr_str(attr)));
 }
 
 void rt_load_method(mp_obj_t base, qstr attr, mp_obj_t *dest) {
-    DEBUG_OP_printf("load method %s\n", qstr_str(attr));
-    if (MP_OBJ_IS_TYPE(base, &gen_instance_type) && attr == MP_QSTR___next__) {
-        dest[1] = (mp_obj_t)&mp_builtin_next_obj;
-        dest[0] = base;
-        return;
-    } else if (MP_OBJ_IS_TYPE(base, &instance_type)) {
-        mp_obj_instance_load_method(base, attr, dest);
-        return;
-    } else if (MP_OBJ_IS_OBJ(base)) {
-        // generic method lookup
-        mp_obj_base_t *o = base;
-        const mp_method_t *meth = o->type->methods;
-        if (meth != NULL) {
-            for (; meth->name != NULL; meth++) {
-                if (strcmp(meth->name, qstr_str(attr)) == 0) {
-                    dest[1] = (mp_obj_t)meth->fun;
-                    dest[0] = base;
-                    return;
+    DEBUG_OP_printf("load method %p.%s\n", base, qstr_str(attr));
+
+    // clear output to indicate no attribute/method found yet
+    dest[0] = MP_OBJ_NULL;
+    dest[1] = MP_OBJ_NULL;
+
+    // get the type
+    mp_obj_type_t *type = mp_obj_get_type(base);
+
+    // if this type can do its own load, then call it
+    if (type->load_attr != NULL) {
+        type->load_attr(base, attr, dest);
+    }
+
+    // if nothing found yet, look for built-in and generic names
+    if (dest[1] == NULL) {
+        if (attr == MP_QSTR___next__ && type->iternext != NULL) {
+            dest[1] = (mp_obj_t)&mp_builtin_next_obj;
+            dest[0] = base;
+        } else {
+            // generic method lookup
+            const mp_method_t *meth = type->methods;
+            if (meth != NULL) {
+                for (; meth->name != NULL; meth++) {
+                    if (strcmp(meth->name, qstr_str(attr)) == 0) {
+                        dest[1] = (mp_obj_t)meth->fun;
+                        dest[0] = base;
+                        break;
+                    }
                 }
             }
         }
     }
 
-    // no method; fallback to load_attr
-    dest[1] = rt_load_attr(base, attr);
-    dest[0] = NULL;
+    if (dest[1] == NULL) {
+        // no attribute/method called attr
+        // following CPython, we give a more detailed error message for type objects
+        if (MP_OBJ_IS_TYPE(base, &mp_const_type)) {
+            nlr_jump(mp_obj_new_exception_msg_varg(MP_QSTR_AttributeError, "type object '%s' has no attribute '%s'", ((mp_obj_type_t*)base)->name, qstr_str(attr)));
+        } else {
+            nlr_jump(mp_obj_new_exception_msg_varg(MP_QSTR_AttributeError, "'%s' object has no attribute '%s'", mp_obj_get_type_str(base), qstr_str(attr)));
+        }
+    }
 }
 
 void rt_store_attr(mp_obj_t base, qstr attr, mp_obj_t value) {
     DEBUG_OP_printf("store attr %p.%s <- %p\n", base, qstr_str(attr), value);
-    if (MP_OBJ_IS_TYPE(base, &class_type)) {
-        // TODO CPython allows STORE_ATTR to a class, but is this the correct implementation?
-        mp_map_t *locals = mp_obj_class_get_locals(base);
-        mp_map_lookup(locals, MP_OBJ_NEW_QSTR(attr), MP_MAP_LOOKUP_ADD_IF_NOT_FOUND)->value = value;
-    } else if (MP_OBJ_IS_TYPE(base, &instance_type)) {
-        mp_obj_instance_store_attr(base, attr, value);
-    } else if (MP_OBJ_IS_TYPE(base, &module_type)) {
-        // TODO CPython allows STORE_ATTR to a module, but is this the correct implementation?
-        mp_map_t *globals = mp_obj_module_get_globals(base);
-        mp_map_lookup(globals, MP_OBJ_NEW_QSTR(attr), MP_MAP_LOOKUP_ADD_IF_NOT_FOUND)->value = value;
-    } else {
-        nlr_jump(mp_obj_new_exception_msg_varg(MP_QSTR_AttributeError, "'%s' object has no attribute '%s'", mp_obj_get_type_str(base), qstr_str(attr)));
+    mp_obj_type_t *type = mp_obj_get_type(base);
+    if (type->store_attr != NULL) {
+        if (type->store_attr(base, attr, value)) {
+            return;
+        }
     }
+    nlr_jump(mp_obj_new_exception_msg_varg(MP_QSTR_AttributeError, "'%s' object has no attribute '%s'", mp_obj_get_type_str(base), qstr_str(attr)));
 }
 
 void rt_store_subscr(mp_obj_t base, mp_obj_t index, mp_obj_t value) {
diff --git a/stm/pybwlan.c b/stm/pybwlan.c
index 8da7bb937b..e890e10ca7 100644
--- a/stm/pybwlan.c
+++ b/stm/pybwlan.c
@@ -65,6 +65,8 @@ void decode_addr_and_store(mp_obj_t object, qstr q_attr, unsigned char *ip, int
     rt_store_attr(object, q_attr, decode_addr(ip, n_bytes));
 }
 
+static mp_obj_t net_address_type = MP_OBJ_NULL;
+
 mp_obj_t pyb_wlan_get_ip(void) {
     tNetappIpconfigRetArgs ipconfig;
     netapp_ipconfig(&ipconfig);
@@ -74,16 +76,24 @@ mp_obj_t pyb_wlan_get_ip(void) {
         return mp_const_none;
     }
 
-    mp_obj_t data = mp_obj_new_class(mp_map_new(0)); // TODO should this be an instance of a class?
-    decode_addr_and_store(data, qstr_from_str_static("ip"), &ipconfig.aucIP[0], 4);
-    decode_addr_and_store(data, qstr_from_str_static("subnet"), &ipconfig.aucSubnetMask[0], 4);
-    decode_addr_and_store(data, qstr_from_str_static("gateway"), &ipconfig.aucDefaultGateway[0], 4);
-    decode_addr_and_store(data, qstr_from_str_static("dhcp"), &ipconfig.aucDHCPServer[0], 4);
-    decode_addr_and_store(data, qstr_from_str_static("dns"), &ipconfig.aucDNSServer[0], 4);
-    decode_addr_and_store(data, qstr_from_str_static("mac"), &ipconfig.uaMacAddr[0], 6);
-    decode_addr_and_store(data, qstr_from_str_static("ssid"), &ipconfig.uaSSID[0], 32);
+    // if it doesn't already exist, make a new empty class for NetAddress objects
+    if (net_address_type == MP_OBJ_NULL) {
+        net_address_type = mp_obj_new_type(qstr_from_str_static("NetAddress"), mp_obj_new_dict(0));
+    }
+
+    // make a new NetAddress object
+    mp_obj_t net_addr = rt_call_function_0(net_address_type);
+
+    // fill the NetAddress object with data
+    decode_addr_and_store(net_addr, qstr_from_str_static("ip"), &ipconfig.aucIP[0], 4);
+    decode_addr_and_store(net_addr, qstr_from_str_static("subnet"), &ipconfig.aucSubnetMask[0], 4);
+    decode_addr_and_store(net_addr, qstr_from_str_static("gateway"), &ipconfig.aucDefaultGateway[0], 4);
+    decode_addr_and_store(net_addr, qstr_from_str_static("dhcp"), &ipconfig.aucDHCPServer[0], 4);
+    decode_addr_and_store(net_addr, qstr_from_str_static("dns"), &ipconfig.aucDNSServer[0], 4);
+    decode_addr_and_store(net_addr, qstr_from_str_static("mac"), &ipconfig.uaMacAddr[0], 6);
+    decode_addr_and_store(net_addr, qstr_from_str_static("ssid"), &ipconfig.uaSSID[0], 32);
 
-    return data;
+    return net_addr;
 }
 
 uint32_t last_ip = 0; // XXX such a hack!
diff --git a/tests/basics/tests/class2.py b/tests/basics/tests/class2.py
index 0b3b218672..64f1f62b96 100644
--- a/tests/basics/tests/class2.py
+++ b/tests/basics/tests/class2.py
@@ -5,6 +5,7 @@ class C1:
         self.x = 1
 
 c1 = C1()
+print(type(c1) == C1)
 print(c1.x)
 
 class C2:
@@ -12,4 +13,5 @@ class C2:
         self.x = x
 
 c2 = C2(4)
+print(type(c2) == C2)
 print(c2.x)
diff --git a/unix/main.c b/unix/main.c
index b29a99f4fa..caec900a52 100644
--- a/unix/main.c
+++ b/unix/main.c
@@ -210,6 +210,18 @@ int main(int argc, char **argv) {
     rt_store_name(qstr_from_str_static("test"), test_obj_new(42));
     rt_store_name(qstr_from_str_static("open"), (mp_obj_t)&mp_builtin_open_obj);
 
+    // Here is some example code to create a class and instance of that class.
+    // First is the Python, then the C code.
+    //
+    // class TestClass:
+    //     pass
+    // test_obj = TestClass()
+    // test_obj.attr = 42
+    mp_obj_t test_class_type, test_class_instance;
+    test_class_type = mp_obj_new_type(qstr_from_str_static("TestClass"), mp_obj_new_dict(0));
+    rt_store_name(qstr_from_str_static("test_obj"), test_class_instance = rt_call_function_0(test_class_type));
+    rt_store_attr(test_class_instance, qstr_from_str_static("attr"), mp_obj_new_int(42));
+
     /*
     printf("bytes:\n");
     printf("    total %d\n", m_get_total_bytes_allocated());