Commit e44d26ae authored by Damien George's avatar Damien George
Browse files

py: Implement __getattr__.

It's not completely satisfactory, because a failed call to __getattr__
should not raise an exception.

__setattr__ could be implemented, but it would slow down all stores to a
user created object.  Need to implement some caching system.
parent 4db727af
......@@ -16,6 +16,7 @@
typedef struct _mp_obj_class_t {
mp_obj_base_t base;
mp_map_t members;
// TODO maybe cache __getattr__ and __setattr__ for efficient lookup of them
} mp_obj_class_t;
STATIC mp_obj_t mp_obj_new_class(mp_obj_t class) {
......@@ -225,6 +226,19 @@ STATIC void class_load_attr(mp_obj_t self_in, qstr attr, mp_obj_t *dest) {
} else {
// class member is a value, so just return that value
dest[0] = member;
}
return;
}
// try __getattr__
if (attr != MP_QSTR___getattr__) {
mp_obj_t dest2[3];
mp_load_method_maybe(self_in, MP_QSTR___getattr__, dest2);
if (dest2[0] != MP_OBJ_NULL) {
// __getattr__ exists, call it and return its result
// XXX if this fails to load the requested attr, should we catch the attribute error and return silently?
dest2[2] = MP_OBJ_NEW_QSTR(attr);
dest[0] = mp_call_method_n_kw(1, 0, dest2);
return;
}
}
......
......@@ -26,6 +26,7 @@ Q(__add__)
Q(__sub__)
Q(__repr__)
Q(__str__)
Q(__getattr__)
Q(micropython)
Q(byte_code)
......
......@@ -701,7 +701,7 @@ mp_obj_t mp_load_attr(mp_obj_t base, qstr attr) {
// no attribute found, returns: dest[0] == MP_OBJ_NULL, dest[1] == MP_OBJ_NULL
// normal attribute found, returns: dest[0] == <attribute>, dest[1] == MP_OBJ_NULL
// method attribute found, returns: dest[0] == <method>, dest[1] == <self>
STATIC void mp_load_method_maybe(mp_obj_t base, qstr attr, mp_obj_t *dest) {
void mp_load_method_maybe(mp_obj_t base, qstr attr, mp_obj_t *dest) {
// clear output to indicate no attribute/method found yet
dest[0] = MP_OBJ_NULL;
dest[1] = MP_OBJ_NULL;
......@@ -709,48 +709,45 @@ STATIC void mp_load_method_maybe(mp_obj_t base, qstr attr, mp_obj_t *dest) {
// 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[0] == MP_OBJ_NULL) {
// look for built-in names
if (0) {
#if MICROPY_CPYTHON_COMPAT
if (attr == MP_QSTR___class__) {
// a.__class__ is equivalent to type(a)
dest[0] = type;
} else
} else if (attr == MP_QSTR___class__) {
// a.__class__ is equivalent to type(a)
dest[0] = type;
#endif
if (attr == MP_QSTR___next__ && type->iternext != NULL) {
dest[0] = (mp_obj_t)&mp_builtin_next_obj;
dest[1] = base;
} else if (type->load_attr == NULL) {
// generic method lookup if type didn't provide a specific one
// this is a lookup in the object (ie not class or type)
if (type->locals_dict != NULL) {
assert(MP_OBJ_IS_TYPE(type->locals_dict, &mp_type_dict)); // Micro Python restriction, for now
mp_map_t *locals_map = mp_obj_dict_get_map(type->locals_dict);
mp_map_elem_t *elem = mp_map_lookup(locals_map, MP_OBJ_NEW_QSTR(attr), MP_MAP_LOOKUP);
if (elem != NULL) {
// check if the methods are functions, static or class methods
// see http://docs.python.org/3.3/howto/descriptor.html
if (MP_OBJ_IS_TYPE(elem->value, &mp_type_staticmethod)) {
// return just the function
dest[0] = ((mp_obj_static_class_method_t*)elem->value)->fun;
} else if (MP_OBJ_IS_TYPE(elem->value, &mp_type_classmethod)) {
// return a bound method, with self being the type of this object
dest[0] = ((mp_obj_static_class_method_t*)elem->value)->fun;
dest[1] = mp_obj_get_type(base);
} else if (mp_obj_is_callable(elem->value)) {
// return a bound method, with self being this object
dest[0] = elem->value;
dest[1] = base;
} else {
// class member is a value, so just return that value
dest[0] = elem->value;
}
}
} else if (attr == MP_QSTR___next__ && type->iternext != NULL) {
dest[0] = (mp_obj_t)&mp_builtin_next_obj;
dest[1] = base;
} else if (type->load_attr != NULL) {
// this type can do its own load, so call it
type->load_attr(base, attr, dest);
} else if (type->locals_dict != NULL) {
// generic method lookup
// this is a lookup in the object (ie not class or type)
assert(MP_OBJ_IS_TYPE(type->locals_dict, &mp_type_dict)); // Micro Python restriction, for now
mp_map_t *locals_map = mp_obj_dict_get_map(type->locals_dict);
mp_map_elem_t *elem = mp_map_lookup(locals_map, MP_OBJ_NEW_QSTR(attr), MP_MAP_LOOKUP);
if (elem != NULL) {
// check if the methods are functions, static or class methods
// see http://docs.python.org/3.3/howto/descriptor.html
if (MP_OBJ_IS_TYPE(elem->value, &mp_type_staticmethod)) {
// return just the function
dest[0] = ((mp_obj_static_class_method_t*)elem->value)->fun;
} else if (MP_OBJ_IS_TYPE(elem->value, &mp_type_classmethod)) {
// return a bound method, with self being the type of this object
dest[0] = ((mp_obj_static_class_method_t*)elem->value)->fun;
dest[1] = mp_obj_get_type(base);
} else if (mp_obj_is_callable(elem->value)) {
// return a bound method, with self being this object
dest[0] = elem->value;
dest[1] = base;
} else {
// class member is a value, so just return that value
dest[0] = elem->value;
}
}
}
......
......@@ -46,6 +46,7 @@ void mp_unpack_sequence(mp_obj_t seq, uint num, mp_obj_t *items);
mp_obj_t mp_store_map(mp_obj_t map, mp_obj_t key, mp_obj_t value);
mp_obj_t mp_load_attr(mp_obj_t base, qstr attr);
void mp_load_method(mp_obj_t base, qstr attr, mp_obj_t *dest);
void mp_load_method_maybe(mp_obj_t base, qstr attr, mp_obj_t *dest);
void mp_store_attr(mp_obj_t base, qstr attr, mp_obj_t val);
void mp_store_subscr(mp_obj_t base, mp_obj_t index, mp_obj_t val);
......
# test __getattr__
class A:
def __init__(self, d):
self.d = d
def __getattr__(self, attr):
return self.d[attr]
a = A({'a':1, 'b':2})
print(a.a, a.b)
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