Builtin Types¶

Generated Sun 02 Jul 2017 11:36:21 UTC

Exception¶

Exception chaining not implemented

Sample code:

try:
    raise TypeError
except TypeError:
    raise ValueError

CPy output:

uPy output:

Traceback (most recent call last):
  File "<stdin>", line 8, in <module>
TypeError

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "<stdin>", line 10, in <module>
ValueError

Traceback (most recent call last):
  File "<stdin>", line 10, in <module>
ValueError:

Assign instance variable to exception

Sample code:

e = Exception()
e.x = 0
print(e.x)

CPy output:	uPy output:
0	Traceback (most recent call last): File "<stdin>", line 8, in <module> AttributeError: 'Exception' object has no attribute 'x'

While loop guards will obscure exception line number reporting due to being optimised onto the end of the code block

Sample code:

l = ["-foo", "-bar"]

i = 0
while l[i][0] == "-":
    print("iter")
    i += 1

CPy output:

uPy output:

iter
iter
Traceback (most recent call last):
  File "<stdin>", line 10, in <module>
IndexError: list index out of range

iter
iter
Traceback (most recent call last):
  File "<stdin>", line 12, in <module>
IndexError: list index out of range

Exception.__init__ raises TypeError if overridden and called by subclass

Sample code:

class A(Exception):
    def __init__(self):
        Exception.__init__(self)

a = A()

CPy output:	uPy output:
	Traceback (most recent call last): File "<stdin>", line 11, in <module> File "<stdin>", line 9, in __init__ TypeError: argument should be a 'Exception' not a 'A'

bytearray¶

Array slice assignment with unsupported RHS

Sample code:

b = bytearray(4)
b[0:1] = [1, 2]
print(b)

CPy output:	uPy output:
bytearray(b'\x01\x02\x00\x00\x00')	Traceback (most recent call last): File "<stdin>", line 8, in <module> NotImplementedError: array/bytes required on right side

bytes¶

bytes(...) with keywords not implemented

Workaround: Input the encoding format directly. eg. print(bytes('abc', 'utf-8'))

Sample code:

print(bytes('abc', encoding='utf8'))

CPy output:	uPy output:
b'abc'	Traceback (most recent call last): File "<stdin>", line 7, in <module> NotImplementedError: keyword argument(s) not yet implemented - use normal args instead

Bytes subscr with step != 1 not implemented

Sample code:

print(b'123'[0:3:2])

CPy output:	uPy output:
b'13'	Traceback (most recent call last): File "<stdin>", line 7, in <module> NotImplementedError: only slices with step=1 (aka None) are supported

float¶

uPy and CPython outputs formats differ

Sample code:

print('%.1g' % -9.9)
print('%.1e' % 9.99)
print('%.1e' % 0.999)

CPy output:	uPy output:
-1e+01 1.0e+01 1.0e+00	-10 1.00e+01 1.00e-00

int¶

No int conversion for int-derived types available

Sample code:

class A(int):
    __add__ = lambda self, other: A(int(self) + other)

a = A(42)
print(a+a)

CPy output:	uPy output:
84	Traceback (most recent call last): File "<stdin>", line 11, in <module> File "<stdin>", line 8, in <lambda> TypeError: can't convert A to int

Incorrect error message when passing float into to_bytes

Sample code:

try:
    int('1').to_bytes(1.0)
except TypeError as e:
    print(e)

CPy output:	uPy output:
integer argument expected, got float	function missing 1 required positional arguments

list¶

List delete with step != 1 not implemented

Sample code:

l = [1, 2, 3, 4]
del l[0:4:2]
print(l)

CPy output:	uPy output:
[2, 4]	Traceback (most recent call last): File "<stdin>", line 8, in <module> NotImplementedError:

List slice-store with non-iterable on RHS is not implemented

Cause: RHS is restricted to be a tuple or list

Workaround: Use list(<iter>) on RHS to convert the iterable to a list

Sample code:

l = [10, 20]
l[0:1] = range(4)
print(l)

CPy output:	uPy output:
[0, 1, 2, 3, 20]	Traceback (most recent call last): File "<stdin>", line 8, in <module> TypeError: object 'range' is not a tuple or list

List store with step != 1 not implemented

Sample code:

l = [1, 2, 3, 4]
l[0:4:2] = [5, 6]
print(l)

CPy output:	uPy output:
[5, 2, 6, 4]	Traceback (most recent call last): File "<stdin>", line 8, in <module> NotImplementedError:

str¶

UnicodeDecodeError not raised when expected

Sample code:

try:
    print(repr(str(b"\xa1\x80", 'utf8')))
    print('Should not get here')
except UnicodeDecodeError:
    print('UnicodeDecodeError')

CPy output:	uPy output:
UnicodeDecodeError	'\u0840' Should not get here

Start/end indices such as str.endswith(s, start) not implemented

Sample code:

print('abc'.endswith('c', 1))

CPy output:	uPy output:
True	Traceback (most recent call last): File "<stdin>", line 7, in <module> NotImplementedError: start/end indices

Attributes/subscr not implemented

Sample code:

print('{a[0]}'.format(a=[1, 2]))

CPy output:	uPy output:
1	Traceback (most recent call last): File "<stdin>", line 7, in <module> NotImplementedError: attributes not supported yet

str(...) with keywords not implemented

Workaround: Input the encoding format directly. eg print(bytes('abc', 'utf-8'))

Sample code:

print(str(b'abc', encoding='utf8'))

CPy output:	uPy output:
abc	Traceback (most recent call last): File "<stdin>", line 7, in <module> NotImplementedError: keyword argument(s) not yet implemented - use normal args instead

None as first argument for rsplit such as str.rsplit(None, n) not implemented

Sample code:

print('a a a'.rsplit(None, 1))

CPy output:	uPy output:
['a a', 'a']	Traceback (most recent call last): File "<stdin>", line 7, in <module> NotImplementedError: rsplit(None,n)

Instance of a subclass of str cannot be compared for equality with an instance of a str

Sample code:

class S(str):
    pass

s = S('hello')
print(s == 'hello')

CPy output:	uPy output:
True	False

Subscript with step != 1 is not yet implemented

Sample code:

print('abcdefghi'[0:9:2])

CPy output:	uPy output:
acegi	Traceback (most recent call last): File "<stdin>", line 7, in <module> NotImplementedError: only slices with step=1 (aka None) are supported

tuple¶

Tuple load with step != 1 not implemented

Sample code:

print((1, 2, 3, 4)[0:4:2])

CPy output:	uPy output:
(1, 3)	Traceback (most recent call last): File "<stdin>", line 7, in <module> NotImplementedError: only slices with step=1 (aka None) are supported