py/obj.c - lite/micropython - Linaro Git Browser

 /*
  * This file is part of the MicroPython project, http://micropython.org/
  *
  * The MIT License (MIT)
  *
  * Copyright (c) 2013, 2014 Damien P. George
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
  * in the Software without restriction, including without limitation the rights
  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  * copies of the Software, and to permit persons to whom the Software is
  * furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  */

 #include <stdint.h>
 #include <stdio.h>
 #include <stdarg.h>
 #include <assert.h>

 #include "py/obj.h"
 #include "py/objtype.h"
 #include "py/objint.h"
 #include "py/objstr.h"
 #include "py/runtime.h"
 #include "py/stackctrl.h"
 #include "py/stream.h" // for mp_obj_print

 // Allocates an object and also sets type, for mp_obj_malloc{,_var} macros.
 MP_NOINLINE void *mp_obj_malloc_helper(size_t num_bytes, const mp_obj_type_t *type) {
     mp_obj_base_t *base = (mp_obj_base_t *)m_malloc(num_bytes);
     base->type = type;
     return base;
 }

 #if MICROPY_ENABLE_FINALISER
 // Allocates an object and also sets type, for mp_obj_malloc{,_var}_with_finaliser macros.
 MP_NOINLINE void *mp_obj_malloc_with_finaliser_helper(size_t num_bytes, const mp_obj_type_t *type) {
     mp_obj_base_t *base = (mp_obj_base_t *)m_malloc_with_finaliser(num_bytes);
     base->type = type;
     return base;
 }
 #endif

 const mp_obj_type_t *MICROPY_WRAP_MP_OBJ_GET_TYPE(mp_obj_get_type)(mp_const_obj_t o_in) {
     #if MICROPY_OBJ_IMMEDIATE_OBJS && MICROPY_OBJ_REPR == MICROPY_OBJ_REPR_A

     if (mp_obj_is_obj(o_in)) {
         const mp_obj_base_t *o = MP_OBJ_TO_PTR(o_in);
         return o->type;
     } else {
         static const mp_obj_type_t *const types[] = {
             NULL, &mp_type_int, &mp_type_str, &mp_type_int,
             NULL, &mp_type_int, &mp_type_NoneType, &mp_type_int,
             NULL, &mp_type_int, &mp_type_str, &mp_type_int,
             NULL, &mp_type_int, &mp_type_bool, &mp_type_int,
         };
         return types[(uintptr_t)o_in & 0xf];
     }

     #elif MICROPY_OBJ_IMMEDIATE_OBJS && MICROPY_OBJ_REPR == MICROPY_OBJ_REPR_C

     if (mp_obj_is_small_int(o_in)) {
         return &mp_type_int;
     } else if (mp_obj_is_obj(o_in)) {
         const mp_obj_base_t *o = MP_OBJ_TO_PTR(o_in);
         return o->type;
     #if MICROPY_PY_BUILTINS_FLOAT
     } else if ((((mp_uint_t)(o_in)) & 0xff800007) != 0x00000006) {
         return &mp_type_float;
     #endif
     } else {
         static const mp_obj_type_t *const types[] = {
             &mp_type_str, &mp_type_NoneType, &mp_type_str, &mp_type_bool,
         };
         return types[((uintptr_t)o_in >> 3) & 3];
     }

     #else

     if (mp_obj_is_small_int(o_in)) {
         return &mp_type_int;
     } else if (mp_obj_is_qstr(o_in)) {
         return &mp_type_str;
         #if MICROPY_PY_BUILTINS_FLOAT && ( \
             MICROPY_OBJ_REPR == MICROPY_OBJ_REPR_C || MICROPY_OBJ_REPR == MICROPY_OBJ_REPR_D)
     } else if (mp_obj_is_float(o_in)) {
         return &mp_type_float;
         #endif
     #if MICROPY_OBJ_IMMEDIATE_OBJS
     } else if (mp_obj_is_immediate_obj(o_in)) {
         static const mp_obj_type_t *const types[2] = {&mp_type_NoneType, &mp_type_bool};
         return types[MP_OBJ_IMMEDIATE_OBJ_VALUE(o_in) & 1];
     #endif
     } else {
         const mp_obj_base_t *o = MP_OBJ_TO_PTR(o_in);
         return o->type;
     }

     #endif
 }

 const char *mp_obj_get_type_str(mp_const_obj_t o_in) {
     return qstr_str(mp_obj_get_type(o_in)->name);
 }

 void mp_obj_print_helper(const mp_print_t *print, mp_obj_t o_in, mp_print_kind_t kind) {
     // There can be data structures nested too deep, or just recursive
     MP_STACK_CHECK();
     #ifndef NDEBUG
     if (o_in == MP_OBJ_NULL) {
         mp_print_str(print, "(nil)");
         return;
     }
     #endif
     const mp_obj_type_t *type = mp_obj_get_type(o_in);
     if (MP_OBJ_TYPE_HAS_SLOT(type, print)) {
         MP_OBJ_TYPE_GET_SLOT(type, print)((mp_print_t *)print, o_in, kind);
     } else {
         mp_printf(print, "<%q>", type->name);
     }
 }

 void mp_obj_print(mp_obj_t o_in, mp_print_kind_t kind) {
     mp_obj_print_helper(MP_PYTHON_PRINTER, o_in, kind);
 }

 // helper function to print an exception with traceback
 void mp_obj_print_exception(const mp_print_t *print, mp_obj_t exc) {
     if (mp_obj_is_exception_instance(exc)) {
         size_t n, *values;
         mp_obj_exception_get_traceback(exc, &n, &values);
         if (n > 0) {
             assert(n % 3 == 0);
             mp_print_str(print, "Traceback (most recent call last):\n");
             for (int i = n - 3; i >= 0; i -= 3) {
                 #if MICROPY_ENABLE_SOURCE_LINE
                 mp_printf(print, "  File \"%q\", line %d", values[i], (int)values[i + 1]);
                 #else
                 mp_printf(print, "  File \"%q\"", values[i]);
                 #endif
                 // the block name can be NULL if it's unknown
                 qstr block = values[i + 2];
                 if (block == MP_QSTRnull) {
                     mp_print_str(print, "\n");
                 } else {
                     mp_printf(print, ", in %q\n", block);
                 }
             }
         }
     }
     mp_obj_print_helper(print, exc, PRINT_EXC);
     mp_print_str(print, "\n");
 }

 bool mp_obj_is_true(mp_obj_t arg) {
     if (arg == mp_const_false) {
         return 0;
     } else if (arg == mp_const_true) {
         return 1;
     } else if (arg == mp_const_none) {
         return 0;
     } else if (mp_obj_is_small_int(arg)) {
         if (arg == MP_OBJ_NEW_SMALL_INT(0)) {
             return 0;
         } else {
             return 1;
         }
     } else {
         const mp_obj_type_t *type = mp_obj_get_type(arg);
         if (MP_OBJ_TYPE_HAS_SLOT(type, unary_op)) {
             mp_obj_t result = MP_OBJ_TYPE_GET_SLOT(type, unary_op)(MP_UNARY_OP_BOOL, arg);
             if (result != MP_OBJ_NULL) {
                 return result == mp_const_true;
             }
         }

         mp_obj_t len = mp_obj_len_maybe(arg);
         if (len != MP_OBJ_NULL) {
             // obj has a length, truth determined if len != 0
             return len != MP_OBJ_NEW_SMALL_INT(0);
         } else {
             // any other obj is true per Python semantics
             return 1;
         }
     }
 }

 bool mp_obj_is_callable(mp_obj_t o_in) {
     const mp_call_fun_t call = MP_OBJ_TYPE_GET_SLOT_OR_NULL(mp_obj_get_type(o_in), call);
     if (call != mp_obj_instance_call) {
         return call != NULL;
     }
     return mp_obj_instance_is_callable(o_in);
 }

 // This function implements the '==' and '!=' operators.
 //
 // From the Python language reference:
 // (https://docs.python.org/3/reference/expressions.html#not-in)
 // "The objects need not have the same type. If both are numbers, they are converted
 // to a common type. Otherwise, the == and != operators always consider objects of
 // different types to be unequal."
 //
 // This means that False==0 and True==1 are true expressions.
 //
 // Furthermore, from the v3.4.2 code for object.c: "Practical amendments: If rich
 // comparison returns NotImplemented, == and != are decided by comparing the object
 // pointer."
 mp_obj_t mp_obj_equal_not_equal(mp_binary_op_t op, mp_obj_t o1, mp_obj_t o2) {
     mp_obj_t local_true = (op == MP_BINARY_OP_NOT_EQUAL) ? mp_const_false : mp_const_true;
     mp_obj_t local_false = (op == MP_BINARY_OP_NOT_EQUAL) ? mp_const_true : mp_const_false;
     int pass_number = 0;

     // Shortcut for very common cases
     if (o1 == o2 &&
         (mp_obj_is_small_int(o1) || !(mp_obj_get_type(o1)->flags & MP_TYPE_FLAG_EQ_NOT_REFLEXIVE))) {
         return local_true;
     }

     // fast path for strings
     if (mp_obj_is_str(o1)) {
         if (mp_obj_is_str(o2)) {
             // both strings, use special function
             return mp_obj_str_equal(o1, o2) ? local_true : local_false;
         #if MICROPY_PY_STR_BYTES_CMP_WARN
         } else if (mp_obj_is_type(o2, &mp_type_bytes)) {
         str_bytes_cmp:
             mp_warning(MP_WARN_CAT(BytesWarning), "Comparison between bytes and str");
             return local_false;
         #endif
         } else {
             goto skip_one_pass;
         }
     #if MICROPY_PY_STR_BYTES_CMP_WARN
     } else if (mp_obj_is_str(o2) && mp_obj_is_type(o1, &mp_type_bytes)) {
         // o1 is not a string (else caught above), so the objects are not equal
         goto str_bytes_cmp;
     #endif
     }

     // fast path for small ints
     if (mp_obj_is_small_int(o1)) {
         if (mp_obj_is_small_int(o2)) {
             // both SMALL_INT, and not equal if we get here
             return local_false;
         } else {
             goto skip_one_pass;
         }
     }

     // generic type, call binary_op(MP_BINARY_OP_EQUAL)
     while (pass_number < 2) {
         const mp_obj_type_t *type = mp_obj_get_type(o1);
         // If a full equality test is not needed and the other object is a different
         // type then we don't need to bother trying the comparison.
         if (MP_OBJ_TYPE_HAS_SLOT(type, binary_op) &&
             ((type->flags & MP_TYPE_FLAG_EQ_CHECKS_OTHER_TYPE) || mp_obj_get_type(o2) == type)) {
             // CPython is asymmetric: it will try __eq__ if there's no __ne__ but not the
             // other way around.  If the class doesn't need a full test we can skip __ne__.
             if (op == MP_BINARY_OP_NOT_EQUAL && (type->flags & MP_TYPE_FLAG_EQ_HAS_NEQ_TEST)) {
                 mp_obj_t r = MP_OBJ_TYPE_GET_SLOT(type, binary_op)(MP_BINARY_OP_NOT_EQUAL, o1, o2);
                 if (r != MP_OBJ_NULL) {
                     return r;
                 }
             }

             // Try calling __eq__.
             mp_obj_t r = MP_OBJ_TYPE_GET_SLOT(type, binary_op)(MP_BINARY_OP_EQUAL, o1, o2);
             if (r != MP_OBJ_NULL) {
                 if (op == MP_BINARY_OP_EQUAL) {
                     return r;
                 } else {
                     return mp_obj_is_true(r) ? local_true : local_false;
                 }
             }
         }

     skip_one_pass:
         // Try the other way around if none of the above worked
         ++pass_number;
         mp_obj_t temp = o1;
         o1 = o2;
         o2 = temp;
     }

     // equality not implemented, so fall back to pointer comparison
     return (o1 == o2) ? local_true : local_false;
 }

 bool mp_obj_equal(mp_obj_t o1, mp_obj_t o2) {
     return mp_obj_is_true(mp_obj_equal_not_equal(MP_BINARY_OP_EQUAL, o1, o2));
 }

 mp_int_t mp_obj_get_int(mp_const_obj_t arg) {
     // This function essentially performs implicit type conversion to int
     // Note that Python does NOT provide implicit type conversion from
     // float to int in the core expression language, try some_list[1.0].
     mp_int_t val;
     if (!mp_obj_get_int_maybe(arg, &val)) {
         mp_raise_TypeError_int_conversion(arg);
     }
     return val;
 }

 mp_int_t mp_obj_get_int_truncated(mp_const_obj_t arg) {
     if (mp_obj_is_int(arg)) {
         return mp_obj_int_get_truncated(arg);
     } else {
         return mp_obj_get_int(arg);
     }
 }

 // returns false if arg is not of integral type
 // returns true and sets *value if it is of integral type
 // can throw OverflowError if arg is of integral type, but doesn't fit in a mp_int_t
 bool mp_obj_get_int_maybe(mp_const_obj_t arg, mp_int_t *value) {
     if (arg == mp_const_false) {
         *value = 0;
     } else if (arg == mp_const_true) {
         *value = 1;
     } else if (mp_obj_is_small_int(arg)) {
         *value = MP_OBJ_SMALL_INT_VALUE(arg);
     } else if (mp_obj_is_exact_type(arg, &mp_type_int)) {
         *value = mp_obj_int_get_checked(arg);
     } else {
         arg = mp_unary_op(MP_UNARY_OP_INT_MAYBE, (mp_obj_t)arg);
         if (arg != MP_OBJ_NULL) {
             *value = mp_obj_int_get_checked(arg);
         } else {
             return false;
         }
     }
     return true;
 }

 #if MICROPY_PY_BUILTINS_FLOAT
 bool mp_obj_get_float_maybe(mp_obj_t arg, mp_float_t *value) {
     mp_float_t val;

     if (arg == mp_const_false) {
         val = 0;
     } else if (arg == mp_const_true) {
         val = 1;
     } else if (mp_obj_is_small_int(arg)) {
         val = (mp_float_t)MP_OBJ_SMALL_INT_VALUE(arg);
     #if MICROPY_LONGINT_IMPL != MICROPY_LONGINT_IMPL_NONE
     } else if (mp_obj_is_exact_type(arg, &mp_type_int)) {
         val = mp_obj_int_as_float_impl(arg);
     #endif
     } else if (mp_obj_is_float(arg)) {
         val = mp_obj_float_get(arg);
     } else {
         arg = mp_unary_op(MP_UNARY_OP_FLOAT_MAYBE, (mp_obj_t)arg);
         if (arg != MP_OBJ_NULL && mp_obj_is_float(arg)) {
             val = mp_obj_float_get(arg);
         } else {
             return false;
         }
     }
     *value = val;
     return true;
 }

 mp_float_t mp_obj_get_float(mp_obj_t arg) {
     mp_float_t val;

     if (!mp_obj_get_float_maybe(arg, &val)) {
         #if MICROPY_ERROR_REPORTING <= MICROPY_ERROR_REPORTING_TERSE
         mp_raise_TypeError(MP_ERROR_TEXT("can't convert to float"));
         #else
         mp_raise_msg_varg(&mp_type_TypeError,
             MP_ERROR_TEXT("can't convert %s to float"), mp_obj_get_type_str(arg));
         #endif
     }

     return val;
 }

 #if MICROPY_PY_BUILTINS_COMPLEX
 bool mp_obj_get_complex_maybe(mp_obj_t arg, mp_float_t *real, mp_float_t *imag) {
     if (mp_obj_get_float_maybe(arg, real)) {
         *imag = 0;
     } else if (mp_obj_is_type(arg, &mp_type_complex)) {
         mp_obj_complex_get(arg, real, imag);
     } else {
         arg = mp_unary_op(MP_UNARY_OP_COMPLEX_MAYBE, (mp_obj_t)arg);
         if (arg != MP_OBJ_NULL && mp_obj_is_type(arg, &mp_type_complex)) {
             mp_obj_complex_get(arg, real, imag);
         } else {
             return false;
         }
     }
     return true;
 }

 void mp_obj_get_complex(mp_obj_t arg, mp_float_t *real, mp_float_t *imag) {
     if (!mp_obj_get_complex_maybe(arg, real, imag)) {
         #if MICROPY_ERROR_REPORTING <= MICROPY_ERROR_REPORTING_TERSE
         mp_raise_TypeError(MP_ERROR_TEXT("can't convert to complex"));
         #else
         mp_raise_msg_varg(&mp_type_TypeError,
             MP_ERROR_TEXT("can't convert %s to complex"), mp_obj_get_type_str(arg));
         #endif
     }
 }
 #endif
 #endif

 // note: returned value in *items may point to the interior of a GC block
 void mp_obj_get_array(mp_obj_t o, size_t *len, mp_obj_t **items) {
     if (mp_obj_is_type(o, &mp_type_tuple)) {
         mp_obj_tuple_get(o, len, items);
     } else if (mp_obj_is_type(o, &mp_type_list)) {
         mp_obj_list_get(o, len, items);
     } else {
         #if MICROPY_ERROR_REPORTING <= MICROPY_ERROR_REPORTING_TERSE
         mp_raise_TypeError(MP_ERROR_TEXT("expected tuple/list"));
         #else
         mp_raise_msg_varg(&mp_type_TypeError,
             MP_ERROR_TEXT("object '%s' isn't a tuple or list"), mp_obj_get_type_str(o));
         #endif
     }
 }

 // note: returned value in *items may point to the interior of a GC block
 void mp_obj_get_array_fixed_n(mp_obj_t o, size_t len, mp_obj_t **items) {
     size_t seq_len;
     mp_obj_get_array(o, &seq_len, items);
     if (seq_len != len) {
         #if MICROPY_ERROR_REPORTING <= MICROPY_ERROR_REPORTING_TERSE
         mp_raise_ValueError(MP_ERROR_TEXT("tuple/list has wrong length"));
         #else
         mp_raise_msg_varg(&mp_type_ValueError,
             MP_ERROR_TEXT("requested length %d but object has length %d"), (int)len, (int)seq_len);
         #endif
     }
 }

 // is_slice determines whether the index is a slice index
 size_t mp_get_index(const mp_obj_type_t *type, size_t len, mp_obj_t index, bool is_slice) {
     mp_int_t i;
     if (mp_obj_is_small_int(index)) {
         i = MP_OBJ_SMALL_INT_VALUE(index);
     } else if (!mp_obj_get_int_maybe(index, &i)) {
         #if MICROPY_ERROR_REPORTING <= MICROPY_ERROR_REPORTING_TERSE
         mp_raise_TypeError(MP_ERROR_TEXT("indices must be integers"));
         #else
         mp_raise_msg_varg(&mp_type_TypeError,
             MP_ERROR_TEXT("%q indices must be integers, not %s"),
             type->name, mp_obj_get_type_str(index));
         #endif
     }

     if (i < 0) {
         i += len;
     }
     if (is_slice) {
         if (i < 0) {
             i = 0;
         } else if ((mp_uint_t)i > len) {
             i = len;
         }
     } else {
         if (i < 0 || (mp_uint_t)i >= len) {
             #if MICROPY_ERROR_REPORTING <= MICROPY_ERROR_REPORTING_TERSE
             mp_raise_msg(&mp_type_IndexError, MP_ERROR_TEXT("index out of range"));
             #else
             mp_raise_msg_varg(&mp_type_IndexError, MP_ERROR_TEXT("%q index out of range"), type->name);
             #endif
         }
     }

     // By this point 0 <= i <= len and so fits in a size_t
     return (size_t)i;
 }

 mp_obj_t mp_obj_id(mp_obj_t o_in) {
     mp_int_t id = (mp_int_t)o_in;
     if (!mp_obj_is_obj(o_in)) {
         return mp_obj_new_int(id);
     } else if (id >= 0) {
         // Many OSes and CPUs have affinity for putting "user" memories
         // into low half of address space, and "system" into upper half.
         // We're going to take advantage of that and return small int
         // (signed) for such "user" addresses.
         return MP_OBJ_NEW_SMALL_INT(id);
     } else {
         // If that didn't work, well, let's return long int, just as
         // a (big) positive value, so it will never clash with the range
         // of small int returned in previous case.
         return mp_obj_new_int_from_uint((mp_uint_t)id);
     }
 }

 // will raise a TypeError if object has no length
 mp_obj_t mp_obj_len(mp_obj_t o_in) {
     mp_obj_t len = mp_obj_len_maybe(o_in);
     if (len == MP_OBJ_NULL) {
         #if MICROPY_ERROR_REPORTING <= MICROPY_ERROR_REPORTING_TERSE
         mp_raise_TypeError(MP_ERROR_TEXT("object has no len"));
         #else
         mp_raise_msg_varg(&mp_type_TypeError,
             MP_ERROR_TEXT("object of type '%s' has no len()"), mp_obj_get_type_str(o_in));
         #endif
     } else {
         return len;
     }
 }

 // may return MP_OBJ_NULL
 mp_obj_t mp_obj_len_maybe(mp_obj_t o_in) {
     if (
         #if !MICROPY_PY_BUILTINS_STR_UNICODE
         // It's simple - unicode is slow, non-unicode is fast
         mp_obj_is_str(o_in) ||
         #endif
         mp_obj_is_type(o_in, &mp_type_bytes)) {
         GET_STR_LEN(o_in, l);
         return MP_OBJ_NEW_SMALL_INT(l);
     } else {
         const mp_obj_type_t *type = mp_obj_get_type(o_in);
         if (MP_OBJ_TYPE_HAS_SLOT(type, unary_op)) {
             return MP_OBJ_TYPE_GET_SLOT(type, unary_op)(MP_UNARY_OP_LEN, o_in);
         } else {
             return MP_OBJ_NULL;
         }
     }
 }

 mp_obj_t mp_obj_subscr(mp_obj_t base, mp_obj_t index, mp_obj_t value) {
     const mp_obj_type_t *type = mp_obj_get_type(base);
     if (MP_OBJ_TYPE_HAS_SLOT(type, subscr)) {
         mp_obj_t ret = MP_OBJ_TYPE_GET_SLOT(type, subscr)(base, index, value);
         if (ret != MP_OBJ_NULL) {
             return ret;
         }
         // TODO: call base classes here?
     }
     if (value == MP_OBJ_NULL) {
         #if MICROPY_ERROR_REPORTING <= MICROPY_ERROR_REPORTING_TERSE
         mp_raise_TypeError(MP_ERROR_TEXT("object doesn't support item deletion"));
         #else
         mp_raise_msg_varg(&mp_type_TypeError,
             MP_ERROR_TEXT("'%s' object doesn't support item deletion"), mp_obj_get_type_str(base));
         #endif
     } else if (value == MP_OBJ_SENTINEL) {
         #if MICROPY_ERROR_REPORTING <= MICROPY_ERROR_REPORTING_TERSE
         mp_raise_TypeError(MP_ERROR_TEXT("object isn't subscriptable"));
         #else
         mp_raise_msg_varg(&mp_type_TypeError,
             MP_ERROR_TEXT("'%s' object isn't subscriptable"), mp_obj_get_type_str(base));
         #endif
     } else {
         #if MICROPY_ERROR_REPORTING <= MICROPY_ERROR_REPORTING_TERSE
         mp_raise_TypeError(MP_ERROR_TEXT("object doesn't support item assignment"));
         #else
         mp_raise_msg_varg(&mp_type_TypeError,
             MP_ERROR_TEXT("'%s' object doesn't support item assignment"), mp_obj_get_type_str(base));
         #endif
     }
 }

 // Return input argument. Useful as .getiter for objects which are
 // their own iterators, etc.
 mp_obj_t mp_identity(mp_obj_t self) {
     return self;
 }
 MP_DEFINE_CONST_FUN_OBJ_1(mp_identity_obj, mp_identity);

 // mp_obj_t mp_identity_getiter(mp_obj_t self, mp_obj_iter_buf_t *iter_buf) {
 //     (void)iter_buf;
 //     return self;
 // }

 bool mp_get_buffer(mp_obj_t obj, mp_buffer_info_t *bufinfo, mp_uint_t flags) {
     const mp_obj_type_t *type = mp_obj_get_type(obj);
     if (MP_OBJ_TYPE_HAS_SLOT(type, buffer)
         && MP_OBJ_TYPE_GET_SLOT(type, buffer)(obj, bufinfo, flags & MP_BUFFER_RW) == 0) {
         return true;
     }
     if (flags & MP_BUFFER_RAISE_IF_UNSUPPORTED) {
         mp_raise_TypeError(MP_ERROR_TEXT("object with buffer protocol required"));
     }
     return false;
 }
	/*
	* This file is part of the MicroPython project, http://micropython.org/
	*
	* The MIT License (MIT)
	*
	* Copyright (c) 2013, 2014 Damien P. George
	*
	* Permission is hereby granted, free of charge, to any person obtaining a copy
	* of this software and associated documentation files (the "Software"), to deal
	* in the Software without restriction, including without limitation the rights
	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	* copies of the Software, and to permit persons to whom the Software is
	* furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice shall be included in
	* all copies or substantial portions of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
	* THE SOFTWARE.
	*/

	#include <stdint.h>
	#include <stdio.h>
	#include <stdarg.h>
	#include <assert.h>

	#include "py/obj.h"
	#include "py/objtype.h"
	#include "py/objint.h"
	#include "py/objstr.h"
	#include "py/runtime.h"
	#include "py/stackctrl.h"
	#include "py/stream.h" // for mp_obj_print

	// Allocates an object and also sets type, for mp_obj_malloc{,_var} macros.
	MP_NOINLINE void mp_obj_malloc_helper(size_t num_bytes, const mp_obj_type_t type) {
	mp_obj_base_t base = (mp_obj_base_t )m_malloc(num_bytes);
	base->type = type;
	return base;
	}

	#if MICROPY_ENABLE_FINALISER
	// Allocates an object and also sets type, for mp_obj_malloc{,_var}_with_finaliser macros.
	MP_NOINLINE void mp_obj_malloc_with_finaliser_helper(size_t num_bytes, const mp_obj_type_t type) {
	mp_obj_base_t base = (mp_obj_base_t )m_malloc_with_finaliser(num_bytes);
	base->type = type;
	return base;
	}
	#endif

	const mp_obj_type_t *MICROPY_WRAP_MP_OBJ_GET_TYPE(mp_obj_get_type)(mp_const_obj_t o_in) {
	#if MICROPY_OBJ_IMMEDIATE_OBJS && MICROPY_OBJ_REPR == MICROPY_OBJ_REPR_A

	if (mp_obj_is_obj(o_in)) {
	const mp_obj_base_t *o = MP_OBJ_TO_PTR(o_in);
	return o->type;
	} else {
	static const mp_obj_type_t *const types[] = {
	NULL, &mp_type_int, &mp_type_str, &mp_type_int,
	NULL, &mp_type_int, &mp_type_NoneType, &mp_type_int,
	NULL, &mp_type_int, &mp_type_str, &mp_type_int,
	NULL, &mp_type_int, &mp_type_bool, &mp_type_int,
	};
	return types[(uintptr_t)o_in & 0xf];
	}

	#elif MICROPY_OBJ_IMMEDIATE_OBJS && MICROPY_OBJ_REPR == MICROPY_OBJ_REPR_C

	if (mp_obj_is_small_int(o_in)) {
	return &mp_type_int;
	} else if (mp_obj_is_obj(o_in)) {
	const mp_obj_base_t *o = MP_OBJ_TO_PTR(o_in);
	return o->type;
	#if MICROPY_PY_BUILTINS_FLOAT
	} else if ((((mp_uint_t)(o_in)) & 0xff800007) != 0x00000006) {
	return &mp_type_float;
	#endif
	} else {
	static const mp_obj_type_t *const types[] = {
	&mp_type_str, &mp_type_NoneType, &mp_type_str, &mp_type_bool,
	};
	return types[((uintptr_t)o_in >> 3) & 3];
	}

	#else

	if (mp_obj_is_small_int(o_in)) {
	return &mp_type_int;
	} else if (mp_obj_is_qstr(o_in)) {
	return &mp_type_str;
	#if MICROPY_PY_BUILTINS_FLOAT && ( \
	MICROPY_OBJ_REPR == MICROPY_OBJ_REPR_C \|\| MICROPY_OBJ_REPR == MICROPY_OBJ_REPR_D)
	} else if (mp_obj_is_float(o_in)) {
	return &mp_type_float;
	#endif
	#if MICROPY_OBJ_IMMEDIATE_OBJS
	} else if (mp_obj_is_immediate_obj(o_in)) {
	static const mp_obj_type_t *const types[2] = {&mp_type_NoneType, &mp_type_bool};
	return types[MP_OBJ_IMMEDIATE_OBJ_VALUE(o_in) & 1];
	#endif
	} else {
	const mp_obj_base_t *o = MP_OBJ_TO_PTR(o_in);
	return o->type;
	}

	#endif
	}

	const char *mp_obj_get_type_str(mp_const_obj_t o_in) {
	return qstr_str(mp_obj_get_type(o_in)->name);
	}

	void mp_obj_print_helper(const mp_print_t *print, mp_obj_t o_in, mp_print_kind_t kind) {
	// There can be data structures nested too deep, or just recursive
	MP_STACK_CHECK();
	#ifndef NDEBUG
	if (o_in == MP_OBJ_NULL) {
	mp_print_str(print, "(nil)");
	return;
	}
	#endif
	const mp_obj_type_t *type = mp_obj_get_type(o_in);
	if (MP_OBJ_TYPE_HAS_SLOT(type, print)) {
	MP_OBJ_TYPE_GET_SLOT(type, print)((mp_print_t *)print, o_in, kind);
	} else {
	mp_printf(print, "<%q>", type->name);
	}
	}

	void mp_obj_print(mp_obj_t o_in, mp_print_kind_t kind) {
	mp_obj_print_helper(MP_PYTHON_PRINTER, o_in, kind);
	}

	// helper function to print an exception with traceback
	void mp_obj_print_exception(const mp_print_t *print, mp_obj_t exc) {
	if (mp_obj_is_exception_instance(exc)) {
	size_t n, *values;
	mp_obj_exception_get_traceback(exc, &n, &values);
	if (n > 0) {
	assert(n % 3 == 0);
	mp_print_str(print, "Traceback (most recent call last):\n");
	for (int i = n - 3; i >= 0; i -= 3) {
	#if MICROPY_ENABLE_SOURCE_LINE
	mp_printf(print, " File \"%q\", line %d", values[i], (int)values[i + 1]);
	#else
	mp_printf(print, " File \"%q\"", values[i]);
	#endif
	// the block name can be NULL if it's unknown
	qstr block = values[i + 2];
	if (block == MP_QSTRnull) {
	mp_print_str(print, "\n");
	} else {
	mp_printf(print, ", in %q\n", block);
	}
	}
	}
	}
	mp_obj_print_helper(print, exc, PRINT_EXC);
	mp_print_str(print, "\n");
	}

	bool mp_obj_is_true(mp_obj_t arg) {
	if (arg == mp_const_false) {
	return 0;
	} else if (arg == mp_const_true) {
	return 1;
	} else if (arg == mp_const_none) {
	return 0;
	} else if (mp_obj_is_small_int(arg)) {
	if (arg == MP_OBJ_NEW_SMALL_INT(0)) {
	return 0;
	} else {
	return 1;
	}
	} else {
	const mp_obj_type_t *type = mp_obj_get_type(arg);
	if (MP_OBJ_TYPE_HAS_SLOT(type, unary_op)) {
	mp_obj_t result = MP_OBJ_TYPE_GET_SLOT(type, unary_op)(MP_UNARY_OP_BOOL, arg);
	if (result != MP_OBJ_NULL) {
	return result == mp_const_true;
	}
	}

	mp_obj_t len = mp_obj_len_maybe(arg);
	if (len != MP_OBJ_NULL) {
	// obj has a length, truth determined if len != 0
	return len != MP_OBJ_NEW_SMALL_INT(0);
	} else {
	// any other obj is true per Python semantics
	return 1;
	}
	}
	}

	bool mp_obj_is_callable(mp_obj_t o_in) {
	const mp_call_fun_t call = MP_OBJ_TYPE_GET_SLOT_OR_NULL(mp_obj_get_type(o_in), call);
	if (call != mp_obj_instance_call) {
	return call != NULL;
	}
	return mp_obj_instance_is_callable(o_in);
	}

	// This function implements the '==' and '!=' operators.
	//
	// From the Python language reference:
	// (https://docs.python.org/3/reference/expressions.html#not-in)
	// "The objects need not have the same type. If both are numbers, they are converted
	// to a common type. Otherwise, the == and != operators always consider objects of
	// different types to be unequal."
	//
	// This means that False==0 and True==1 are true expressions.
	//
	// Furthermore, from the v3.4.2 code for object.c: "Practical amendments: If rich
	// comparison returns NotImplemented, == and != are decided by comparing the object
	// pointer."
	mp_obj_t mp_obj_equal_not_equal(mp_binary_op_t op, mp_obj_t o1, mp_obj_t o2) {
	mp_obj_t local_true = (op == MP_BINARY_OP_NOT_EQUAL) ? mp_const_false : mp_const_true;
	mp_obj_t local_false = (op == MP_BINARY_OP_NOT_EQUAL) ? mp_const_true : mp_const_false;
	int pass_number = 0;

	// Shortcut for very common cases
	if (o1 == o2 &&
	(mp_obj_is_small_int(o1) \|\| !(mp_obj_get_type(o1)->flags & MP_TYPE_FLAG_EQ_NOT_REFLEXIVE))) {
	return local_true;
	}

	// fast path for strings
	if (mp_obj_is_str(o1)) {
	if (mp_obj_is_str(o2)) {
	// both strings, use special function
	return mp_obj_str_equal(o1, o2) ? local_true : local_false;
	#if MICROPY_PY_STR_BYTES_CMP_WARN
	} else if (mp_obj_is_type(o2, &mp_type_bytes)) {
	str_bytes_cmp:
	mp_warning(MP_WARN_CAT(BytesWarning), "Comparison between bytes and str");
	return local_false;
	#endif
	} else {
	goto skip_one_pass;
	}
	#if MICROPY_PY_STR_BYTES_CMP_WARN
	} else if (mp_obj_is_str(o2) && mp_obj_is_type(o1, &mp_type_bytes)) {
	// o1 is not a string (else caught above), so the objects are not equal
	goto str_bytes_cmp;
	#endif
	}

	// fast path for small ints
	if (mp_obj_is_small_int(o1)) {
	if (mp_obj_is_small_int(o2)) {
	// both SMALL_INT, and not equal if we get here
	return local_false;
	} else {
	goto skip_one_pass;
	}
	}

	// generic type, call binary_op(MP_BINARY_OP_EQUAL)
	while (pass_number < 2) {
	const mp_obj_type_t *type = mp_obj_get_type(o1);
	// If a full equality test is not needed and the other object is a different
	// type then we don't need to bother trying the comparison.
	if (MP_OBJ_TYPE_HAS_SLOT(type, binary_op) &&
	((type->flags & MP_TYPE_FLAG_EQ_CHECKS_OTHER_TYPE) \|\| mp_obj_get_type(o2) == type)) {
	// CPython is asymmetric: it will try __eq__ if there's no __ne__ but not the
	// other way around. If the class doesn't need a full test we can skip __ne__.
	if (op == MP_BINARY_OP_NOT_EQUAL && (type->flags & MP_TYPE_FLAG_EQ_HAS_NEQ_TEST)) {
	mp_obj_t r = MP_OBJ_TYPE_GET_SLOT(type, binary_op)(MP_BINARY_OP_NOT_EQUAL, o1, o2);
	if (r != MP_OBJ_NULL) {
	return r;
	}
	}

	// Try calling __eq__.
	mp_obj_t r = MP_OBJ_TYPE_GET_SLOT(type, binary_op)(MP_BINARY_OP_EQUAL, o1, o2);
	if (r != MP_OBJ_NULL) {
	if (op == MP_BINARY_OP_EQUAL) {
	return r;
	} else {
	return mp_obj_is_true(r) ? local_true : local_false;
	}
	}
	}

	skip_one_pass:
	// Try the other way around if none of the above worked
	++pass_number;
	mp_obj_t temp = o1;
	o1 = o2;
	o2 = temp;
	}

	// equality not implemented, so fall back to pointer comparison
	return (o1 == o2) ? local_true : local_false;
	}

	bool mp_obj_equal(mp_obj_t o1, mp_obj_t o2) {
	return mp_obj_is_true(mp_obj_equal_not_equal(MP_BINARY_OP_EQUAL, o1, o2));
	}

	mp_int_t mp_obj_get_int(mp_const_obj_t arg) {
	// This function essentially performs implicit type conversion to int
	// Note that Python does NOT provide implicit type conversion from
	// float to int in the core expression language, try some_list[1.0].
	mp_int_t val;
	if (!mp_obj_get_int_maybe(arg, &val)) {
	mp_raise_TypeError_int_conversion(arg);
	}
	return val;
	}

	mp_int_t mp_obj_get_int_truncated(mp_const_obj_t arg) {
	if (mp_obj_is_int(arg)) {
	return mp_obj_int_get_truncated(arg);
	} else {
	return mp_obj_get_int(arg);
	}
	}

	// returns false if arg is not of integral type
	// returns true and sets *value if it is of integral type
	// can throw OverflowError if arg is of integral type, but doesn't fit in a mp_int_t
	bool mp_obj_get_int_maybe(mp_const_obj_t arg, mp_int_t *value) {
	if (arg == mp_const_false) {
	*value = 0;
	} else if (arg == mp_const_true) {
	*value = 1;
	} else if (mp_obj_is_small_int(arg)) {
	*value = MP_OBJ_SMALL_INT_VALUE(arg);
	} else if (mp_obj_is_exact_type(arg, &mp_type_int)) {
	*value = mp_obj_int_get_checked(arg);
	} else {
	arg = mp_unary_op(MP_UNARY_OP_INT_MAYBE, (mp_obj_t)arg);
	if (arg != MP_OBJ_NULL) {
	*value = mp_obj_int_get_checked(arg);
	} else {
	return false;
	}
	}
	return true;
	}

	#if MICROPY_PY_BUILTINS_FLOAT
	bool mp_obj_get_float_maybe(mp_obj_t arg, mp_float_t *value) {
	mp_float_t val;

	if (arg == mp_const_false) {
	val = 0;
	} else if (arg == mp_const_true) {
	val = 1;
	} else if (mp_obj_is_small_int(arg)) {
	val = (mp_float_t)MP_OBJ_SMALL_INT_VALUE(arg);
	#if MICROPY_LONGINT_IMPL != MICROPY_LONGINT_IMPL_NONE
	} else if (mp_obj_is_exact_type(arg, &mp_type_int)) {
	val = mp_obj_int_as_float_impl(arg);
	#endif
	} else if (mp_obj_is_float(arg)) {
	val = mp_obj_float_get(arg);
	} else {
	arg = mp_unary_op(MP_UNARY_OP_FLOAT_MAYBE, (mp_obj_t)arg);
	if (arg != MP_OBJ_NULL && mp_obj_is_float(arg)) {
	val = mp_obj_float_get(arg);
	} else {
	return false;
	}
	}
	*value = val;
	return true;
	}

	mp_float_t mp_obj_get_float(mp_obj_t arg) {
	mp_float_t val;

	if (!mp_obj_get_float_maybe(arg, &val)) {
	#if MICROPY_ERROR_REPORTING <= MICROPY_ERROR_REPORTING_TERSE
	mp_raise_TypeError(MP_ERROR_TEXT("can't convert to float"));
	#else
	mp_raise_msg_varg(&mp_type_TypeError,
	MP_ERROR_TEXT("can't convert %s to float"), mp_obj_get_type_str(arg));
	#endif
	}

	return val;
	}

	#if MICROPY_PY_BUILTINS_COMPLEX
	bool mp_obj_get_complex_maybe(mp_obj_t arg, mp_float_t real, mp_float_t imag) {
	if (mp_obj_get_float_maybe(arg, real)) {
	*imag = 0;
	} else if (mp_obj_is_type(arg, &mp_type_complex)) {
	mp_obj_complex_get(arg, real, imag);
	} else {
	arg = mp_unary_op(MP_UNARY_OP_COMPLEX_MAYBE, (mp_obj_t)arg);
	if (arg != MP_OBJ_NULL && mp_obj_is_type(arg, &mp_type_complex)) {
	mp_obj_complex_get(arg, real, imag);
	} else {
	return false;
	}
	}
	return true;
	}

	void mp_obj_get_complex(mp_obj_t arg, mp_float_t real, mp_float_t imag) {
	if (!mp_obj_get_complex_maybe(arg, real, imag)) {
	#if MICROPY_ERROR_REPORTING <= MICROPY_ERROR_REPORTING_TERSE
	mp_raise_TypeError(MP_ERROR_TEXT("can't convert to complex"));
	#else
	mp_raise_msg_varg(&mp_type_TypeError,
	MP_ERROR_TEXT("can't convert %s to complex"), mp_obj_get_type_str(arg));
	#endif
	}
	}
	#endif
	#endif

	// note: returned value in *items may point to the interior of a GC block
	void mp_obj_get_array(mp_obj_t o, size_t len, mp_obj_t *items) {
	if (mp_obj_is_type(o, &mp_type_tuple)) {
	mp_obj_tuple_get(o, len, items);
	} else if (mp_obj_is_type(o, &mp_type_list)) {
	mp_obj_list_get(o, len, items);
	} else {
	#if MICROPY_ERROR_REPORTING <= MICROPY_ERROR_REPORTING_TERSE
	mp_raise_TypeError(MP_ERROR_TEXT("expected tuple/list"));
	#else
	mp_raise_msg_varg(&mp_type_TypeError,
	MP_ERROR_TEXT("object '%s' isn't a tuple or list"), mp_obj_get_type_str(o));
	#endif
	}
	}

	// note: returned value in *items may point to the interior of a GC block
	void mp_obj_get_array_fixed_n(mp_obj_t o, size_t len, mp_obj_t **items) {
	size_t seq_len;
	mp_obj_get_array(o, &seq_len, items);
	if (seq_len != len) {
	#if MICROPY_ERROR_REPORTING <= MICROPY_ERROR_REPORTING_TERSE
	mp_raise_ValueError(MP_ERROR_TEXT("tuple/list has wrong length"));
	#else
	mp_raise_msg_varg(&mp_type_ValueError,
	MP_ERROR_TEXT("requested length %d but object has length %d"), (int)len, (int)seq_len);
	#endif
	}
	}

	// is_slice determines whether the index is a slice index
	size_t mp_get_index(const mp_obj_type_t *type, size_t len, mp_obj_t index, bool is_slice) {
	mp_int_t i;
	if (mp_obj_is_small_int(index)) {
	i = MP_OBJ_SMALL_INT_VALUE(index);
	} else if (!mp_obj_get_int_maybe(index, &i)) {
	#if MICROPY_ERROR_REPORTING <= MICROPY_ERROR_REPORTING_TERSE
	mp_raise_TypeError(MP_ERROR_TEXT("indices must be integers"));
	#else
	mp_raise_msg_varg(&mp_type_TypeError,
	MP_ERROR_TEXT("%q indices must be integers, not %s"),
	type->name, mp_obj_get_type_str(index));
	#endif
	}

	if (i < 0) {
	i += len;
	}
	if (is_slice) {
	if (i < 0) {
	i = 0;
	} else if ((mp_uint_t)i > len) {
	i = len;
	}
	} else {
	if (i < 0 \|\| (mp_uint_t)i >= len) {
	#if MICROPY_ERROR_REPORTING <= MICROPY_ERROR_REPORTING_TERSE
	mp_raise_msg(&mp_type_IndexError, MP_ERROR_TEXT("index out of range"));
	#else
	mp_raise_msg_varg(&mp_type_IndexError, MP_ERROR_TEXT("%q index out of range"), type->name);
	#endif
	}
	}

	// By this point 0 <= i <= len and so fits in a size_t
	return (size_t)i;
	}

	mp_obj_t mp_obj_id(mp_obj_t o_in) {
	mp_int_t id = (mp_int_t)o_in;
	if (!mp_obj_is_obj(o_in)) {
	return mp_obj_new_int(id);
	} else if (id >= 0) {
	// Many OSes and CPUs have affinity for putting "user" memories
	// into low half of address space, and "system" into upper half.
	// We're going to take advantage of that and return small int
	// (signed) for such "user" addresses.
	return MP_OBJ_NEW_SMALL_INT(id);
	} else {
	// If that didn't work, well, let's return long int, just as
	// a (big) positive value, so it will never clash with the range
	// of small int returned in previous case.
	return mp_obj_new_int_from_uint((mp_uint_t)id);
	}
	}

	// will raise a TypeError if object has no length
	mp_obj_t mp_obj_len(mp_obj_t o_in) {
	mp_obj_t len = mp_obj_len_maybe(o_in);
	if (len == MP_OBJ_NULL) {
	#if MICROPY_ERROR_REPORTING <= MICROPY_ERROR_REPORTING_TERSE
	mp_raise_TypeError(MP_ERROR_TEXT("object has no len"));
	#else
	mp_raise_msg_varg(&mp_type_TypeError,
	MP_ERROR_TEXT("object of type '%s' has no len()"), mp_obj_get_type_str(o_in));
	#endif
	} else {
	return len;
	}
	}

	// may return MP_OBJ_NULL
	mp_obj_t mp_obj_len_maybe(mp_obj_t o_in) {
	if (
	#if !MICROPY_PY_BUILTINS_STR_UNICODE
	// It's simple - unicode is slow, non-unicode is fast
	mp_obj_is_str(o_in) \|\|
	#endif
	mp_obj_is_type(o_in, &mp_type_bytes)) {
	GET_STR_LEN(o_in, l);
	return MP_OBJ_NEW_SMALL_INT(l);
	} else {
	const mp_obj_type_t *type = mp_obj_get_type(o_in);
	if (MP_OBJ_TYPE_HAS_SLOT(type, unary_op)) {
	return MP_OBJ_TYPE_GET_SLOT(type, unary_op)(MP_UNARY_OP_LEN, o_in);
	} else {
	return MP_OBJ_NULL;
	}
	}
	}

	mp_obj_t mp_obj_subscr(mp_obj_t base, mp_obj_t index, mp_obj_t value) {
	const mp_obj_type_t *type = mp_obj_get_type(base);
	if (MP_OBJ_TYPE_HAS_SLOT(type, subscr)) {
	mp_obj_t ret = MP_OBJ_TYPE_GET_SLOT(type, subscr)(base, index, value);
	if (ret != MP_OBJ_NULL) {
	return ret;
	}
	// TODO: call base classes here?
	}
	if (value == MP_OBJ_NULL) {
	#if MICROPY_ERROR_REPORTING <= MICROPY_ERROR_REPORTING_TERSE
	mp_raise_TypeError(MP_ERROR_TEXT("object doesn't support item deletion"));
	#else
	mp_raise_msg_varg(&mp_type_TypeError,
	MP_ERROR_TEXT("'%s' object doesn't support item deletion"), mp_obj_get_type_str(base));
	#endif
	} else if (value == MP_OBJ_SENTINEL) {
	#if MICROPY_ERROR_REPORTING <= MICROPY_ERROR_REPORTING_TERSE
	mp_raise_TypeError(MP_ERROR_TEXT("object isn't subscriptable"));
	#else
	mp_raise_msg_varg(&mp_type_TypeError,
	MP_ERROR_TEXT("'%s' object isn't subscriptable"), mp_obj_get_type_str(base));
	#endif
	} else {
	#if MICROPY_ERROR_REPORTING <= MICROPY_ERROR_REPORTING_TERSE
	mp_raise_TypeError(MP_ERROR_TEXT("object doesn't support item assignment"));
	#else
	mp_raise_msg_varg(&mp_type_TypeError,
	MP_ERROR_TEXT("'%s' object doesn't support item assignment"), mp_obj_get_type_str(base));
	#endif
	}
	}

	// Return input argument. Useful as .getiter for objects which are
	// their own iterators, etc.
	mp_obj_t mp_identity(mp_obj_t self) {
	return self;
	}
	MP_DEFINE_CONST_FUN_OBJ_1(mp_identity_obj, mp_identity);

	// mp_obj_t mp_identity_getiter(mp_obj_t self, mp_obj_iter_buf_t *iter_buf) {
	// (void)iter_buf;
	// return self;
	// }

	bool mp_get_buffer(mp_obj_t obj, mp_buffer_info_t *bufinfo, mp_uint_t flags) {
	const mp_obj_type_t *type = mp_obj_get_type(obj);
	if (MP_OBJ_TYPE_HAS_SLOT(type, buffer)
	&& MP_OBJ_TYPE_GET_SLOT(type, buffer)(obj, bufinfo, flags & MP_BUFFER_RW) == 0) {
	return true;
	}
	if (flags & MP_BUFFER_RAISE_IF_UNSUPPORTED) {
	mp_raise_TypeError(MP_ERROR_TEXT("object with buffer protocol required"));
	}
	return false;
	}