Application: gvSIG desktop » gvSIG scripting

"""

Checks that value used in a subscript supports subscription

(i.e. defines __getitem__ method).

"""

# pylint: disable=missing-docstring,pointless-statement,expression-not-assigned,wrong-import-position

# pylint: disable=too-few-public-methods,import-error,invalid-name,wrong-import-order

import six

# primitives

numbers = [1, 2, 3]

numbers[0]

"123"[0]

u"123"[0]

b"123"[0]

bytearray(b"123")[0]

dict(a=1, b=2)['a']

(1, 2, 3)[0]

# list/dict comprehensions are fine

[x for x in range(10)][0]

{x: 10 - x for x in range(10)}[0]

# instances

class NonSubscriptable(object):

    pass

class Subscriptable(object):

    def __getitem__(self, key):

        return key + key

NonSubscriptable()[0]  # [unsubscriptable-object]

NonSubscriptable[0]  # [unsubscriptable-object]

Subscriptable()[0]

Subscriptable[0]  # [unsubscriptable-object]

# generators are not subscriptable

def powers_of_two():

    k = 0

    while k < 10:

        yield 2 ** k

        k += 1

powers_of_two()[0]  # [unsubscriptable-object]

powers_of_two[0]  # [unsubscriptable-object]

# check that primitive non subscriptable types are catched

True[0]  # [unsubscriptable-object]

None[0]  # [unsubscriptable-object]

8.5[0]  # [unsubscriptable-object]

10[0]  # [unsubscriptable-object]

# sets are not subscriptable

{x ** 2 for x in range(10)}[0]  # [unsubscriptable-object]

set(numbers)[0]  # [unsubscriptable-object]

frozenset(numbers)[0]  # [unsubscriptable-object]

# skip instances with unknown base classes

from some_missing_module import LibSubscriptable

class MaybeSubscriptable(LibSubscriptable):

    pass

MaybeSubscriptable()[0]

# subscriptable classes (through metaclasses)

class MetaSubscriptable(type):

    def __getitem__(cls, key):

        return key + key

class SubscriptableClass(six.with_metaclass(MetaSubscriptable, object)):

    pass

SubscriptableClass[0]

SubscriptableClass()[0]  # [unsubscriptable-object]

# functions are not subscriptable

def test(*args, **kwargs):

    return args, kwargs

test()[0]

test[0]  # [unsubscriptable-object]

# deque

from collections import deque

deq = deque(maxlen=10)

deq.append(42)

deq[0]

class AbstractClass(object):

    def __init__(self):

        self.ala = {i for i in range(10)}

        self.bala = [i for i in range(10)]

        self.portocala = None

    def test_unsubscriptable(self):

        self.bala[0]

        self.portocala[0]

class ClassMixin(object):

    def __init__(self):

        self.ala = {i for i in range(10)}

        self.bala = [i for i in range(10)]

        self.portocala = None

    def test_unsubscriptable(self):

        self.bala[0]

        self.portocala[0]