3f6ffe059f
This commit implements PEP479 which disallows raising StopIteration inside a generator to signal that it should be finished. Instead, the generator should simply return when it is complete. See https://www.python.org/dev/peps/pep-0479/ for details.
261 lines
10 KiB
C
261 lines
10 KiB
C
/*
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* This file is part of the MicroPython project, http://micropython.org/
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*
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* The MIT License (MIT)
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*
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* Copyright (c) 2013, 2014 Damien P. George
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* Copyright (c) 2014-2017 Paul Sokolovsky
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include <stdlib.h>
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#include <assert.h>
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#include "py/runtime.h"
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#include "py/bc.h"
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#include "py/objgenerator.h"
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#include "py/objfun.h"
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#include "py/stackctrl.h"
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/******************************************************************************/
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/* generator wrapper */
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typedef struct _mp_obj_gen_instance_t {
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mp_obj_base_t base;
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mp_obj_dict_t *globals;
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mp_code_state_t code_state;
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} mp_obj_gen_instance_t;
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STATIC mp_obj_t gen_wrap_call(mp_obj_t self_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
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// A generating function is just a bytecode function with type mp_type_gen_wrap
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mp_obj_fun_bc_t *self_fun = MP_OBJ_TO_PTR(self_in);
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// bytecode prelude: get state size and exception stack size
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size_t n_state = mp_decode_uint_value(self_fun->bytecode);
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size_t n_exc_stack = mp_decode_uint_value(mp_decode_uint_skip(self_fun->bytecode));
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// allocate the generator object, with room for local stack and exception stack
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mp_obj_gen_instance_t *o = m_new_obj_var(mp_obj_gen_instance_t, byte,
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n_state * sizeof(mp_obj_t) + n_exc_stack * sizeof(mp_exc_stack_t));
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o->base.type = &mp_type_gen_instance;
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o->globals = self_fun->globals;
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o->code_state.fun_bc = self_fun;
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o->code_state.ip = 0;
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mp_setup_code_state(&o->code_state, n_args, n_kw, args);
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return MP_OBJ_FROM_PTR(o);
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}
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const mp_obj_type_t mp_type_gen_wrap = {
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{ &mp_type_type },
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.name = MP_QSTR_generator,
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.call = gen_wrap_call,
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.unary_op = mp_generic_unary_op,
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#if MICROPY_PY_FUNCTION_ATTRS
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.attr = mp_obj_fun_bc_attr,
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#endif
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};
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/******************************************************************************/
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/* generator instance */
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STATIC void gen_instance_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
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(void)kind;
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mp_obj_gen_instance_t *self = MP_OBJ_TO_PTR(self_in);
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mp_printf(print, "<generator object '%q' at %p>", mp_obj_fun_get_name(MP_OBJ_FROM_PTR(self->code_state.fun_bc)), self);
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}
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mp_vm_return_kind_t mp_obj_gen_resume(mp_obj_t self_in, mp_obj_t send_value, mp_obj_t throw_value, mp_obj_t *ret_val) {
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MP_STACK_CHECK();
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mp_check_self(MP_OBJ_IS_TYPE(self_in, &mp_type_gen_instance));
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mp_obj_gen_instance_t *self = MP_OBJ_TO_PTR(self_in);
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if (self->code_state.ip == 0) {
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// Trying to resume already stopped generator
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*ret_val = MP_OBJ_STOP_ITERATION;
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return MP_VM_RETURN_NORMAL;
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}
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if (self->code_state.sp == self->code_state.state - 1) {
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if (send_value != mp_const_none) {
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mp_raise_TypeError("can't send non-None value to a just-started generator");
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}
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} else {
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#if MICROPY_PY_GENERATOR_PEND_THROW
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// If exception is pending (set using .pend_throw()), process it now.
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if (*self->code_state.sp != mp_const_none) {
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throw_value = *self->code_state.sp;
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*self->code_state.sp = MP_OBJ_NULL;
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} else
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#endif
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{
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*self->code_state.sp = send_value;
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}
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}
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// We set self->globals=NULL while executing, for a sentinel to ensure the generator
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// cannot be reentered during execution
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if (self->globals == NULL) {
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mp_raise_ValueError("generator already executing");
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}
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// Set up the correct globals context for the generator and execute it
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self->code_state.old_globals = mp_globals_get();
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mp_globals_set(self->globals);
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self->globals = NULL;
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mp_vm_return_kind_t ret_kind = mp_execute_bytecode(&self->code_state, throw_value);
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self->globals = mp_globals_get();
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mp_globals_set(self->code_state.old_globals);
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switch (ret_kind) {
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case MP_VM_RETURN_NORMAL:
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default:
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// Explicitly mark generator as completed. If we don't do this,
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// subsequent next() may re-execute statements after last yield
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// again and again, leading to side effects.
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// TODO: check how return with value behaves under such conditions
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// in CPython.
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self->code_state.ip = 0;
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*ret_val = *self->code_state.sp;
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break;
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case MP_VM_RETURN_YIELD:
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*ret_val = *self->code_state.sp;
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#if MICROPY_PY_GENERATOR_PEND_THROW
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*self->code_state.sp = mp_const_none;
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#endif
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break;
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case MP_VM_RETURN_EXCEPTION: {
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size_t n_state = mp_decode_uint_value(self->code_state.fun_bc->bytecode);
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self->code_state.ip = 0;
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*ret_val = self->code_state.state[n_state - 1];
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// PEP479: if StopIteration is raised inside a generator it is replaced with RuntimeError
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if (mp_obj_is_subclass_fast(MP_OBJ_FROM_PTR(mp_obj_get_type(*ret_val)), MP_OBJ_FROM_PTR(&mp_type_StopIteration))) {
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*ret_val = mp_obj_new_exception_msg(&mp_type_RuntimeError, "generator raised StopIteration");
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}
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break;
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}
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}
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return ret_kind;
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}
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STATIC mp_obj_t gen_resume_and_raise(mp_obj_t self_in, mp_obj_t send_value, mp_obj_t throw_value) {
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mp_obj_t ret;
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switch (mp_obj_gen_resume(self_in, send_value, throw_value, &ret)) {
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case MP_VM_RETURN_NORMAL:
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default:
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// Optimize return w/o value in case generator is used in for loop
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if (ret == mp_const_none || ret == MP_OBJ_STOP_ITERATION) {
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return MP_OBJ_STOP_ITERATION;
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} else {
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nlr_raise(mp_obj_new_exception_args(&mp_type_StopIteration, 1, &ret));
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}
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case MP_VM_RETURN_YIELD:
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return ret;
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case MP_VM_RETURN_EXCEPTION:
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nlr_raise(ret);
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}
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}
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STATIC mp_obj_t gen_instance_iternext(mp_obj_t self_in) {
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return gen_resume_and_raise(self_in, mp_const_none, MP_OBJ_NULL);
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}
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STATIC mp_obj_t gen_instance_send(mp_obj_t self_in, mp_obj_t send_value) {
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mp_obj_t ret = gen_resume_and_raise(self_in, send_value, MP_OBJ_NULL);
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if (ret == MP_OBJ_STOP_ITERATION) {
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nlr_raise(mp_obj_new_exception(&mp_type_StopIteration));
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} else {
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return ret;
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}
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}
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STATIC MP_DEFINE_CONST_FUN_OBJ_2(gen_instance_send_obj, gen_instance_send);
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STATIC mp_obj_t gen_instance_close(mp_obj_t self_in);
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STATIC mp_obj_t gen_instance_throw(size_t n_args, const mp_obj_t *args) {
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mp_obj_t exc = (n_args == 2) ? args[1] : args[2];
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mp_obj_t ret = gen_resume_and_raise(args[0], mp_const_none, exc);
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if (ret == MP_OBJ_STOP_ITERATION) {
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nlr_raise(mp_obj_new_exception(&mp_type_StopIteration));
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} else {
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return ret;
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}
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}
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STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(gen_instance_throw_obj, 2, 4, gen_instance_throw);
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STATIC mp_obj_t gen_instance_close(mp_obj_t self_in) {
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mp_obj_t ret;
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switch (mp_obj_gen_resume(self_in, mp_const_none, MP_OBJ_FROM_PTR(&mp_const_GeneratorExit_obj), &ret)) {
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case MP_VM_RETURN_YIELD:
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mp_raise_msg(&mp_type_RuntimeError, "generator ignored GeneratorExit");
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// Swallow GeneratorExit (== successful close), and re-raise any other
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case MP_VM_RETURN_EXCEPTION:
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// ret should always be an instance of an exception class
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if (mp_obj_is_subclass_fast(MP_OBJ_FROM_PTR(mp_obj_get_type(ret)), MP_OBJ_FROM_PTR(&mp_type_GeneratorExit))) {
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return mp_const_none;
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}
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nlr_raise(ret);
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default:
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// The only choice left is MP_VM_RETURN_NORMAL which is successful close
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return mp_const_none;
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}
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}
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STATIC MP_DEFINE_CONST_FUN_OBJ_1(gen_instance_close_obj, gen_instance_close);
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STATIC mp_obj_t gen_instance_pend_throw(mp_obj_t self_in, mp_obj_t exc_in) {
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mp_obj_gen_instance_t *self = MP_OBJ_TO_PTR(self_in);
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if (self->code_state.sp == self->code_state.state - 1) {
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mp_raise_TypeError("can't pend throw to just-started generator");
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}
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mp_obj_t prev = *self->code_state.sp;
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*self->code_state.sp = exc_in;
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return prev;
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}
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STATIC MP_DEFINE_CONST_FUN_OBJ_2(gen_instance_pend_throw_obj, gen_instance_pend_throw);
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STATIC const mp_rom_map_elem_t gen_instance_locals_dict_table[] = {
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{ MP_ROM_QSTR(MP_QSTR_close), MP_ROM_PTR(&gen_instance_close_obj) },
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{ MP_ROM_QSTR(MP_QSTR_send), MP_ROM_PTR(&gen_instance_send_obj) },
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{ MP_ROM_QSTR(MP_QSTR_throw), MP_ROM_PTR(&gen_instance_throw_obj) },
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#if MICROPY_PY_GENERATOR_PEND_THROW
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{ MP_ROM_QSTR(MP_QSTR_pend_throw), MP_ROM_PTR(&gen_instance_pend_throw_obj) },
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#endif
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};
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STATIC MP_DEFINE_CONST_DICT(gen_instance_locals_dict, gen_instance_locals_dict_table);
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const mp_obj_type_t mp_type_gen_instance = {
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{ &mp_type_type },
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.name = MP_QSTR_generator,
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.print = gen_instance_print,
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.unary_op = mp_generic_unary_op,
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.getiter = mp_identity_getiter,
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.iternext = gen_instance_iternext,
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.locals_dict = (mp_obj_dict_t*)&gen_instance_locals_dict,
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};
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