Commit 7c9c6676 authored by Damien George's avatar Damien George
Browse files

py: Implement iterator support for object that has __getitem__.

Addresses Issue #203.
parent fcd4ae82
......@@ -39,7 +39,7 @@ typedef struct _mp_obj_base_t mp_obj_base_t;
#define MP_OBJ_IS_SMALL_INT(o) ((((mp_small_int_t)(o)) & 1) != 0)
#define MP_OBJ_IS_QSTR(o) ((((mp_small_int_t)(o)) & 3) == 2)
#define MP_OBJ_IS_OBJ(o) ((((mp_small_int_t)(o)) & 3) == 0)
#define MP_OBJ_IS_TYPE(o, t) (MP_OBJ_IS_OBJ(o) && (((mp_obj_base_t*)(o))->type == (t)))
#define MP_OBJ_IS_TYPE(o, t) (MP_OBJ_IS_OBJ(o) && (((mp_obj_base_t*)(o))->type == (t))) // this does not work for checking a string, use below macro for that
#define MP_OBJ_IS_STR(o) (MP_OBJ_IS_QSTR(o) || MP_OBJ_IS_TYPE(o, &str_type))
#define MP_OBJ_SMALL_INT_VALUE(o) (((mp_small_int_t)(o)) >> 1)
......@@ -231,6 +231,7 @@ 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 meth, mp_obj_t self);
mp_obj_t mp_obj_new_getitem_iter(mp_obj_t *args);
mp_obj_t mp_obj_new_module(qstr module_name);
mp_obj_type_t *mp_obj_get_type(mp_obj_t o_in);
......
#include <stdlib.h>
#include <stdint.h>
#include "nlr.h"
#include "misc.h"
#include "mpconfig.h"
#include "qstr.h"
#include "obj.h"
#include "runtime.h"
// this is a wrapper object that is turns something that has a __getitem__ method into an iterator
typedef struct _mp_obj_getitem_iter_t {
mp_obj_base_t base;
mp_obj_t args[3];
} mp_obj_getitem_iter_t;
static mp_obj_t it_iternext(mp_obj_t self_in) {
mp_obj_getitem_iter_t *self = self_in;
nlr_buf_t nlr;
if (nlr_push(&nlr) == 0) {
// try to get next item
mp_obj_t value = rt_call_method_n_kw(1, 0, self->args);
self->args[2] = MP_OBJ_NEW_SMALL_INT(MP_OBJ_SMALL_INT_VALUE(self->args[2]) + 1);
nlr_pop();
return value;
} else {
// an exception was raised
if (MP_OBJ_IS_TYPE(nlr.ret_val, &exception_type) && mp_obj_exception_get_type(nlr.ret_val) == MP_QSTR_StopIteration) {
// return mp_const_stop_iteration instead of raising StopIteration
return mp_const_stop_iteration;
} else {
// re-raise exception
nlr_jump(nlr.ret_val);
}
}
}
static const mp_obj_type_t it_type = {
{ &mp_const_type },
"iterator",
.iternext = it_iternext
};
// args are those returned from rt_load_method_maybe (ie either an attribute or a method)
mp_obj_t mp_obj_new_getitem_iter(mp_obj_t *args) {
mp_obj_getitem_iter_t *o = m_new_obj(mp_obj_getitem_iter_t);
o->base.type = &it_type;
o->args[0] = args[0];
o->args[1] = args[1];
o->args[2] = MP_OBJ_NEW_SMALL_INT(0);
return o;
}
......@@ -77,7 +77,7 @@ mp_obj_t str_binary_op(int op, mp_obj_t lhs_in, mp_obj_t rhs_in) {
if (MP_OBJ_IS_SMALL_INT(rhs_in)) {
uint index = mp_get_index(mp_obj_get_type(lhs_in), lhs_len, rhs_in);
if (MP_OBJ_IS_TYPE(lhs_in, &bytes_type)) {
return MP_OBJ_NEW_SMALL_INT(lhs_data[index]);
return MP_OBJ_NEW_SMALL_INT((mp_small_int_t)lhs_data[index]);
} else {
return mp_obj_new_str(lhs_data + index, 1, true);
}
......@@ -549,7 +549,7 @@ mp_obj_t bytes_it_iternext(mp_obj_t self_in) {
mp_obj_str_it_t *self = self_in;
GET_STR_DATA_LEN(self->str, str, len);
if (self->cur < len) {
mp_obj_t o_out = MP_OBJ_NEW_SMALL_INT(str[self->cur]);
mp_obj_t o_out = MP_OBJ_NEW_SMALL_INT((mp_small_int_t)str[self->cur]);
self->cur += 1;
return o_out;
} else {
......
......@@ -117,8 +117,8 @@ static mp_obj_t class_make_new(mp_obj_t self_in, uint n_args, uint n_kw, const m
}
// TODO somehow replace const char * with a qstr
static const char *binary_op_method_name[] = {
[RT_BINARY_OP_SUBSCR] = "__getitem__",
static const qstr binary_op_method_name[] = {
[RT_BINARY_OP_SUBSCR] = MP_QSTR___getitem__,
/*
RT_BINARY_OP_OR,
RT_BINARY_OP_XOR,
......@@ -126,8 +126,8 @@ static const char *binary_op_method_name[] = {
RT_BINARY_OP_LSHIFT,
RT_BINARY_OP_RSHIFT,
*/
[RT_BINARY_OP_ADD] = "__add__",
[RT_BINARY_OP_SUBTRACT] = "__sub__",
[RT_BINARY_OP_ADD] = MP_QSTR___add__,
[RT_BINARY_OP_SUBTRACT] = MP_QSTR___sub__,
/*
RT_BINARY_OP_MULTIPLY,
RT_BINARY_OP_FLOOR_DIVIDE,
......@@ -157,16 +157,16 @@ static const char *binary_op_method_name[] = {
RT_COMPARE_OP_IS,
RT_COMPARE_OP_IS_NOT,
*/
[RT_COMPARE_OP_EXCEPTION_MATCH] = "__not_implemented__",
[RT_COMPARE_OP_EXCEPTION_MATCH] = MP_QSTR_, // not implemented, used to make sure array has full size
};
static mp_obj_t class_binary_op(int op, mp_obj_t lhs_in, mp_obj_t rhs_in) {
mp_obj_class_t *lhs = lhs_in;
const char *op_name = binary_op_method_name[op];
if (op_name == NULL) {
qstr op_name = binary_op_method_name[op];
if (op_name == 0) {
return MP_OBJ_NULL;
}
mp_obj_t member = mp_obj_class_lookup(lhs->base.type, QSTR_FROM_STR_STATIC(op_name));
mp_obj_t member = mp_obj_class_lookup(lhs->base.type, op_name);
if (member != MP_OBJ_NULL) {
return rt_call_function_2(member, lhs_in, rhs_in);
} else {
......
......@@ -47,6 +47,7 @@ PY_O_BASENAME = \
objfloat.o \
objfun.o \
objgenerator.o \
objgetitemiter.o \
objint.o \
objint_longlong.o \
objlist.o \
......
......@@ -13,6 +13,10 @@ Q(__next__)
Q(__qualname__)
Q(__repl_print__)
Q(__getitem__)
Q(__add__)
Q(__sub__)
Q(micropython)
Q(byte_code)
Q(native)
......
......@@ -87,7 +87,7 @@ void rt_init(void) {
// init loaded modules table
mp_map_init(&map_loaded_modules, 3);
// built-in exceptions (TODO, make these proper classes)
// built-in exceptions (TODO, make these proper classes, and const if possible)
mp_map_add_qstr(&map_builtins, MP_QSTR_AttributeError, mp_obj_new_exception(MP_QSTR_AttributeError));
mp_map_add_qstr(&map_builtins, MP_QSTR_IndexError, mp_obj_new_exception(MP_QSTR_IndexError));
mp_map_add_qstr(&map_builtins, MP_QSTR_KeyError, mp_obj_new_exception(MP_QSTR_KeyError));
......@@ -100,6 +100,7 @@ void rt_init(void) {
mp_map_add_qstr(&map_builtins, MP_QSTR_OverflowError, mp_obj_new_exception(MP_QSTR_OverflowError));
mp_map_add_qstr(&map_builtins, MP_QSTR_OSError, mp_obj_new_exception(MP_QSTR_OSError));
mp_map_add_qstr(&map_builtins, MP_QSTR_AssertionError, mp_obj_new_exception(MP_QSTR_AssertionError));
mp_map_add_qstr(&map_builtins, MP_QSTR_StopIteration, mp_obj_new_exception(MP_QSTR_StopIteration));
// built-in objects
mp_map_add_qstr(&map_builtins, MP_QSTR_Ellipsis, mp_const_ellipsis);
......@@ -805,7 +806,7 @@ mp_obj_t rt_load_attr(mp_obj_t base, qstr attr) {
// use load_method
mp_obj_t dest[2];
rt_load_method(base, attr, dest);
if (dest[1] == NULL) {
if (dest[1] == MP_OBJ_NULL) {
// load_method returned just a normal attribute
return dest[0];
} else {
......@@ -814,9 +815,10 @@ mp_obj_t rt_load_attr(mp_obj_t base, qstr attr) {
}
}
void rt_load_method(mp_obj_t base, qstr attr, mp_obj_t *dest) {
DEBUG_OP_printf("load method %p.%s\n", base, qstr_str(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 rt_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;
......@@ -830,7 +832,7 @@ void rt_load_method(mp_obj_t base, qstr attr, mp_obj_t *dest) {
}
// if nothing found yet, look for built-in and generic names
if (dest[0] == NULL) {
if (dest[0] == MP_OBJ_NULL) {
if (attr == MP_QSTR___next__ && type->iternext != NULL) {
dest[0] = (mp_obj_t)&mp_builtin_next_obj;
dest[1] = base;
......@@ -861,8 +863,14 @@ void rt_load_method(mp_obj_t base, qstr attr, mp_obj_t *dest) {
}
}
}
}
void rt_load_method(mp_obj_t base, qstr attr, mp_obj_t *dest) {
DEBUG_OP_printf("load method %p.%s\n", base, qstr_str(attr));
rt_load_method_maybe(base, attr, dest);
if (dest[0] == NULL) {
if (dest[0] == MP_OBJ_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)) {
......@@ -910,7 +918,16 @@ mp_obj_t rt_getiter(mp_obj_t o_in) {
if (type->getiter != NULL) {
return type->getiter(o_in);
} else {
nlr_jump(mp_obj_new_exception_msg_varg(MP_QSTR_TypeError, "'%s' object is not iterable", type->name));
// check for __getitem__ method
mp_obj_t dest[2];
rt_load_method_maybe(o_in, qstr_from_str("__getitem__"), dest);
if (dest[0] != MP_OBJ_NULL) {
// __getitem__ exists, create an iterator
return mp_obj_new_getitem_iter(dest);
} else {
// object not iterable
nlr_jump(mp_obj_new_exception_msg_varg(MP_QSTR_TypeError, "'%s' object is not iterable", type->name));
}
}
}
......
# create a class that has a __getitem__ method
class A:
def __getitem__(self, index):
print('getitem', index)
if index > 10:
raise StopIteration
# test __getitem__
A()[0]
A()[1]
# iterate using a for loop
for i in A():
pass
# iterate manually
it = iter(A())
try:
while True:
next(it)
except StopIteration:
pass
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