ch11-24: clean up by @eumiro & sync with Atlas

Author: ramalho

11-pythonic-obj/private/.gitignore

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+*.class
+.jython_cache/

13-protocol-abc/README.rst

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+Sample code for Chapter 11 - "Interfaces, protocols and ABCs"
+
+From the book "Fluent Python" by Luciano Ramalho (O'Reilly, 2015)
+http://shop.oreilly.com/product/0636920032519.do

13-protocol-abc/bingo.py

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+# tag::TOMBOLA_BINGO[]
+
+import random
+
+from tombola import Tombola
+
+
+class BingoCage(Tombola):  # <1>
+
+    def __init__(self, items):
+        self._randomizer = random.SystemRandom()  # <2>
+        self._items = []
+        self.load(items)  # <3>
+
+    def load(self, items):
+        self._items.extend(items)
+        self._randomizer.shuffle(self._items)  # <4>
+
+    def pick(self):  # <5>
+        try:
+            return self._items.pop()
+        except IndexError:
+            raise LookupError('pick from empty BingoCage')
+
+    def __call__(self):  # <6>
+        self.pick()
+
+# end::TOMBOLA_BINGO[]

13-protocol-abc/double/double_object.py

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+def double(x: object) -> object:
+    return x * 2

13-protocol-abc/double/double_protocol.py

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+from typing import TypeVar, Protocol
+
+T = TypeVar('T')  # <1>
+
+class Repeatable(Protocol):
+    def __mul__(self: T, repeat_count: int) -> T: ...  # <2>
+
+RT = TypeVar('RT', bound=Repeatable)  # <3>
+
+def double(x: RT) -> RT:  # <4>
+    return x * 2

13-protocol-abc/double/double_sequence.py

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+from collections import abc
+from typing import Any
+
+def double(x: abc.Sequence) -> Any:
+    return x * 2
+

13-protocol-abc/double/double_test.py

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+from typing import TYPE_CHECKING
+import pytest
+from double_protocol import double
+
+def test_double_int() -> None:
+    given = 2
+    result = double(given)
+    assert result == given * 2
+    if TYPE_CHECKING:
+        reveal_type(given)
+        reveal_type(result)
+
+
+def test_double_str() -> None:
+    given = 'A'
+    result = double(given)
+    assert result == given * 2
+    if TYPE_CHECKING:
+        reveal_type(given)
+        reveal_type(result)
+
+
+def test_double_fraction() -> None:
+    from fractions import Fraction
+    given = Fraction(2, 5)
+    result = double(given)
+    assert result == given * 2
+    if TYPE_CHECKING:
+        reveal_type(given)
+        reveal_type(result)
+
+
+def test_double_array() -> None:
+    from array import array
+    given = array('d', [1.0, 2.0, 3.14])
+    result = double(given)
+    if TYPE_CHECKING:
+        reveal_type(given)
+        reveal_type(result)
+
+
+def test_double_nparray() -> None:
+    import numpy as np  # type: ignore
+    given = np.array([[1, 2], [3, 4]])
+    result = double(given)
+    comparison = result == given * 2
+    assert comparison.all()
+    if TYPE_CHECKING:
+        reveal_type(given)
+        reveal_type(result)
+
+
+def test_double_none() -> None:
+    given = None
+    with pytest.raises(TypeError):
+        result = double(given)

13-protocol-abc/drum.py

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+from random import shuffle
+
+from tombola import Tombola
+
+
+class TumblingDrum(Tombola):
+
+    def __init__(self, iterable):
+        self._balls = []
+        self.load(iterable)
+
+    def load(self, iterable):
+        self._balls.extend(iterable)
+        shuffle(self._balls)
+
+    def pick(self):
+        return self._balls.pop()

13-protocol-abc/frenchdeck2.py

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+import collections
+
+Card = collections.namedtuple('Card', ['rank', 'suit'])
+
+class FrenchDeck2(collections.MutableSequence):
+    ranks = [str(n) for n in range(2, 11)] + list('JQKA')
+    suits = 'spades diamonds clubs hearts'.split()
+
+    def __init__(self):
+        self._cards = [Card(rank, suit) for suit in self.suits
+                                        for rank in self.ranks]
+
+    def __len__(self):
+        return len(self._cards)
+
+    def __getitem__(self, position):
+        return self._cards[position]
+
+    def __setitem__(self, position, value):  # <1>
+        self._cards[position] = value
+
+    def __delitem__(self, position):  # <2>
+        del self._cards[position]
+
+    def insert(self, position, value):  # <3>
+        self._cards.insert(position, value)

13-protocol-abc/lotto.py

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+# tag::LOTTERY_BLOWER[]
+
+import random
+
+from tombola import Tombola
+
+
+class LotteryBlower(Tombola):
+
+    def __init__(self, iterable):
+        self._balls = list(iterable)  # <1>
+
+    def load(self, iterable):
+        self._balls.extend(iterable)
+
+    def pick(self):
+        try:
+            position = random.randrange(len(self._balls))  # <2>
+        except ValueError:
+            raise LookupError('pick from empty BingoCage')
+        return self._balls.pop(position)  # <3>
+
+    def loaded(self):  # <4>
+        return bool(self._balls)
+
+    def inspect(self):  # <5>
+        return tuple(sorted(self._balls))
+
+
+# end::LOTTERY_BLOWER[]

13-protocol-abc/tombola.py

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+# tag::TOMBOLA_ABC[]
+
+import abc
+
+class Tombola(abc.ABC):  # <1>
+
+    @abc.abstractmethod
+    def load(self, iterable):  # <2>
+        """Add items from an iterable."""
+
+    @abc.abstractmethod
+    def pick(self):  # <3>
+        """Remove item at random, returning it.
+
+        This method should raise `LookupError` when the instance is empty.
+        """
+
+    def loaded(self):  # <4>
+        """Return `True` if there's at least 1 item, `False` otherwise."""
+        return bool(self.inspect())  # <5>
+
+
+    def inspect(self):
+        """Return a sorted tuple with the items currently inside."""
+        items = []
+        while True:  # <6>
+            try:
+                items.append(self.pick())
+            except LookupError:
+                break
+        self.load(items)  # <7>
+        return tuple(sorted(items))
+
+
+# end::TOMBOLA_ABC[]

13-protocol-abc/tombola_runner.py

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+# tag::TOMBOLA_RUNNER[]
+import doctest
+
+from tombola import Tombola
+
+# modules to test
+import bingo, lotto, tombolist, drum  # <1>
+
+TEST_FILE = 'tombola_tests.rst'
+TEST_MSG = '{0:16} {1.attempted:2} tests, {1.failed:2} failed - {2}'
+
+
+def main(argv):
+    verbose = '-v' in argv
+    real_subclasses = Tombola.__subclasses__()  # <2>
+    virtual_subclasses = list(Tombola._abc_registry)  # <3>
+
+    for cls in real_subclasses + virtual_subclasses:  # <4>
+        test(cls, verbose)
+
+
+def test(cls, verbose=False):
+
+    res = doctest.testfile(
+            TEST_FILE,
+            globs={'ConcreteTombola': cls},  # <5>
+            verbose=verbose,
+            optionflags=doctest.REPORT_ONLY_FIRST_FAILURE)
+    tag = 'FAIL' if res.failed else 'OK'
+    print(TEST_MSG.format(cls.__name__, res, tag))  # <6>
+
+
+if __name__ == '__main__':
+    import sys
+    main(sys.argv)
+# end::TOMBOLA_RUNNER[]

13-protocol-abc/tombola_subhook.py

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+"""
+Variation of ``tombola.Tombola`` implementing ``__subclasshook__``.
+
+Tests with simple classes::
+
+    >>> Tombola.__subclasshook__(object)
+    NotImplemented
+    >>> class Complete:
+    ...     def __init__(): pass
+    ...     def load(): pass
+    ...     def pick(): pass
+    ...     def loaded(): pass
+    ...
+    >>> Tombola.__subclasshook__(Complete)
+    True
+    >>> issubclass(Complete, Tombola)
+
+"""
+
+
+from abc import ABC, abstractmethod
+from inspect import getmembers, isfunction
+
+
+class Tombola(ABC):  # <1>
+
+    @abstractmethod
+    def __init__(self, iterable):  # <2>
+        """New instance is loaded from an iterable."""
+
+    @abstractmethod
+    def load(self, iterable):
+        """Add items from an iterable."""
+
+    @abstractmethod
+    def pick(self):  # <3>
+        """Remove item at random, returning it.
+
+        This method should raise `LookupError` when the instance is empty.
+        """
+
+    def loaded(self):  # <4>
+        try:
+            item = self.pick()
+        except LookupError:
+            return False
+        else:
+            self.load([item])  # put it back
+            return True
+
+    @classmethod
+    def __subclasshook__(cls, other_cls):
+        if cls is Tombola:
+            interface_names = function_names(cls)
+            found_names = set()
+            for a_cls in other_cls.__mro__:
+                found_names |= function_names(a_cls)
+            if found_names >= interface_names:
+                return True
+        return NotImplemented
+
+
+def function_names(obj):
+    return {name for name, _ in getmembers(obj, isfunction)}