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Runtime implementation of TypedDict #322

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9395206
Some first thoughts
ilevkivskyi Nov 5, 2016
2c41219
Actual implementation + tests
ilevkivskyi Nov 6, 2016
3509b3c
Backport TypedDict to Python 2
ilevkivskyi Nov 6, 2016
c30d349
Fix typo in 3.6 test
ilevkivskyi Nov 6, 2016
32a3735
Nicer docstrings, add TypedDict to __all__ in PY2
ilevkivskyi Nov 6, 2016
1469035
Prohbit isinstance and issubclass for TypedDict
ilevkivskyi Nov 17, 2016
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54 changes: 53 additions & 1 deletion python2/test_typing.py
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Original file line number Diff line number Diff line change
Expand Up @@ -17,7 +17,7 @@
from typing import cast
from typing import Type
from typing import NewType
from typing import NamedTuple
from typing import NamedTuple, TypedDict
from typing import IO, TextIO, BinaryIO
from typing import Pattern, Match
import abc
Expand Down Expand Up @@ -1432,6 +1432,58 @@ class D(UserName):
pass


class TypedDictTests(BaseTestCase):

def test_basics_fields_syntax(self):
# Check that two iterables allowed
Emp = TypedDict('Emp', [('name', str), ('id', int)])
Emp = TypedDict('Emp', {'name': str, 'id': int})
self.assertIsSubclass(Emp, dict)
jim = Emp(name='Jim', id=1)
self.assertIsInstance(jim, Emp)
self.assertIsInstance(jim, dict)
self.assertEqual(jim['name'], 'Jim')
self.assertEqual(jim['id'], 1)
self.assertEqual(Emp.__name__, 'Emp')
self.assertEqual(Emp.__bases__, (dict,))
self.assertEqual(Emp.__annotations__, {'name': str, 'id': int})

def test_basics_keywords_syntax(self):
Emp = TypedDict('Emp', name=str, id=int)
self.assertIsSubclass(Emp, dict)
jim = Emp(name='Jim', id=1)
self.assertIsInstance(jim, Emp)
self.assertIsInstance(jim, dict)
self.assertEqual(jim['name'], 'Jim')
self.assertEqual(jim['id'], 1)
self.assertEqual(Emp.__name__, 'Emp')
self.assertEqual(Emp.__bases__, (dict,))
self.assertEqual(Emp.__annotations__, {'name': str, 'id': int})

def test_typeddict_errors(self):
Emp = TypedDict('Emp', {'name': str, 'id': int})
with self.assertRaises(TypeError):
isinstance({}, Emp)
with self.assertRaises(TypeError):
issubclass(dict, Emp)
with self.assertRaises(TypeError):
TypedDict('Hi', x=1)
with self.assertRaises(TypeError):
TypedDict('Hi', [('x', int), ('y', 1)])
with self.assertRaises(TypeError):
TypedDict('Hi', [('x', int)], y=int)

def test_pickle(self):
global EmpD # pickle wants to reference the class by name
EmpD = TypedDict('EmpD', name=str, id=int)
jane = EmpD({'name': 'jane', 'id': 37})
for proto in range(pickle.HIGHEST_PROTOCOL + 1):
z = pickle.dumps(jane, proto)
jane2 = pickle.loads(z)
self.assertEqual(jane2, jane)
self.assertEqual(jane2, {'name': 'jane', 'id': 37})


class NamedTupleTests(BaseTestCase):

def test_basics(self):
Expand Down
48 changes: 48 additions & 0 deletions python2/typing.py
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Original file line number Diff line number Diff line change
Expand Up @@ -57,6 +57,7 @@
'Set',
'FrozenSet',
'NamedTuple', # Not really a type.
'TypedDict',
'Generator',

# One-off things.
Expand Down Expand Up @@ -1813,6 +1814,53 @@ def NamedTuple(typename, fields):
return cls


def _check_fails(cls, other):
if sys._getframe(1).f_globals['__name__'] not in ['abc', 'functools']:
raise TypeError('TypedDict does not support instance and class checks')


class TypedDictMeta(type):

def __new__(cls, name, bases, ns):
tp_dict = super(TypedDictMeta, cls).__new__(cls, str(name), (dict,), ns)
try:
tp_dict.__module__ = sys._getframe(2).f_globals.get('__name__', '__main__')
except (AttributeError, ValueError):
pass
anns = ns.get('__annotations__', {})
msg = "TypedDict('Name', {f0: t0, f1: t1, ...}); each t must be a type"
anns = {n: _type_check(tp, msg) for n, tp in anns.items()}
for base in bases:
anns.update(base.__dict__.get('__annotations__', {}))
tp_dict.__annotations__ = anns
return tp_dict

__instancecheck__ = __subclasscheck__ = _check_fails


class TypedDict(object):
"""A simple typed name space. At runtime it is equivalent to a plain dict.
Usage::

Point2D = TypedDict('Point2D', {'x': int, 'y': int, 'label': str})
assert Point2D(x=1, y=2, label='first') == dict(x=1, y=2, label='first')

The type info could be accessed via Point2D.__annotations__. TypedDict supports
one additional equivalent form::

Point2D = TypedDict('Point2D', x=int, y=int, label=str)
"""
__metaclass__ = TypedDictMeta

def __new__(cls, _typename, fields=None, **kwargs):
if fields is None:
fields = kwargs
elif kwargs:
raise TypeError("Either list of fields or keywords"
" can be provided to TypedDict, not both")
return cls.__class__(_typename, (), {'__annotations__': dict(fields)})


def NewType(name, tp):
"""NewType creates simple unique types with almost zero
runtime overhead. NewType(name, tp) is considered a subtype of tp
Expand Down
71 changes: 70 additions & 1 deletion src/test_typing.py
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Original file line number Diff line number Diff line change
Expand Up @@ -18,7 +18,7 @@
from typing import no_type_check, no_type_check_decorator
from typing import Type
from typing import NewType
from typing import NamedTuple
from typing import NamedTuple, TypedDict
from typing import IO, TextIO, BinaryIO
from typing import Pattern, Match
import abc
Expand Down Expand Up @@ -1309,6 +1309,14 @@ class G(Generic[T]):
class CoolEmployee(NamedTuple):
name: str
cool: int

Label = TypedDict('Label', [('label', str)])

class Point2D(TypedDict):
x: int
y: int

class LabelPoint2D(Point2D, Label): ...
"""

if PY36:
Expand Down Expand Up @@ -1805,6 +1813,67 @@ class D(UserName):
pass


class TypedDictTests(BaseTestCase):

def test_basics_iterable_syntax(self):
# Check that two iterables allowed
Emp = TypedDict('Emp', [('name', str), ('id', int)])
Emp = TypedDict('Emp', {'name': str, 'id': int})
self.assertIsSubclass(Emp, dict)
jim = Emp(name='Jim', id=1)
self.assertIsInstance(jim, Emp)
self.assertIsInstance(jim, dict)
self.assertEqual(jim['name'], 'Jim')
self.assertEqual(jim['id'], 1)
self.assertEqual(Emp.__name__, 'Emp')
self.assertEqual(Emp.__bases__, (dict,))
self.assertEqual(Emp.__annotations__, {'name': str, 'id': int})

def test_basics_keywords_syntax(self):
Emp = TypedDict('Emp', name=str, id=int)
self.assertIsSubclass(Emp, dict)
jim = Emp(name='Jim', id=1)
self.assertIsInstance(jim, Emp)
self.assertIsInstance(jim, dict)
self.assertEqual(jim['name'], 'Jim')
self.assertEqual(jim['id'], 1)
self.assertEqual(Emp.__name__, 'Emp')
self.assertEqual(Emp.__bases__, (dict,))
self.assertEqual(Emp.__annotations__, {'name': str, 'id': int})

def test_typeddict_errors(self):
Emp = TypedDict('Emp', {'name': str, 'id': int})
with self.assertRaises(TypeError):
isinstance({}, Emp)
with self.assertRaises(TypeError):
issubclass(dict, Emp)
with self.assertRaises(TypeError):
TypedDict('Hi', x=1)
with self.assertRaises(TypeError):
TypedDict('Hi', [('x', int), ('y', 1)])
with self.assertRaises(TypeError):
TypedDict('Hi', [('x', int)], y=int)

@skipUnless(PY36, 'Python 3.6 required')
def test_class_syntax_usage(self):
self.assertEqual(LabelPoint2D.__annotations__, {'x': int, 'y': int, 'label': str})
self.assertEqual(LabelPoint2D.__bases__, (dict,))
not_origin = Point2D(x=0, y=1)
self.assertEqual(not_origin['x'], 0)
self.assertEqual(not_origin['y'], 1)
other = LabelPoint2D(x=0, y=1, label='hi')
self.assertEqual(other['label'], 'hi')

def test_pickle(self):
global EmpD # pickle wants to reference the class by name
EmpD = TypedDict('EmpD', name=str, id=int)
jane = EmpD({'name': 'jane', 'id': 37})
for proto in range(pickle.HIGHEST_PROTOCOL + 1):
z = pickle.dumps(jane, proto)
jane2 = pickle.loads(z)
self.assertEqual(jane2, jane)
self.assertEqual(jane2, {'name': 'jane', 'id': 37})

class NamedTupleTests(BaseTestCase):

def test_basics(self):
Expand Down
54 changes: 54 additions & 0 deletions src/typing.py
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Original file line number Diff line number Diff line change
Expand Up @@ -67,6 +67,7 @@
'Set',
'FrozenSet',
'NamedTuple', # Not really a type.
'TypedDict',
'Generator',

# One-off things.
Expand Down Expand Up @@ -2001,6 +2002,59 @@ def NamedTuple(typename, fields):
return _make_nmtuple(typename, fields)


def _check_fails(cls, other):
if sys._getframe(1).f_globals['__name__'] not in ['abc', 'functools']:
raise TypeError('TypedDict does not support instance and class checks')


class TypedDictMeta(type):

def __new__(cls, name, bases, ns):
tp_dict = super().__new__(cls, name, (dict,), ns)
try:
tp_dict.__module__ = sys._getframe(2).f_globals.get('__name__', '__main__')
except (AttributeError, ValueError):
pass
anns = ns.get('__annotations__', {})
msg = "TypedDict('Name', {f0: t0, f1: t1, ...}); each t must be a type"
anns = {n: _type_check(tp, msg) for n, tp in anns.items()}
for base in bases:
anns.update(base.__dict__.get('__annotations__', {}))
tp_dict.__annotations__ = anns
return tp_dict

__instancecheck__ = __subclasscheck__ = _check_fails


class TypedDict(metaclass=TypedDictMeta):
"""A simple typed name space. At runtime it is equivalent to a plain dict.
Usage::

Point2D = TypedDict('Point2D', {'x': int, 'y': int, 'label': str})
assert Point2D(x=1, y=2, label='first') == dict(x=1, y=2, label='first')

The type info could be accessed via Point2D.__annotations__. TypedDict supports
two additional equivalent forms::

Point2D = TypedDict('Point2D', x=int, y=int, label=str)

class Point2D(TypedDict):
x: int
y: int
label: str

The latter syntax is only supported in Python 3.6+
"""

def __new__(cls, _typename, fields=None, **kwargs):
if fields is None:
fields = kwargs
elif kwargs:
raise TypeError("Either list of fields or keywords"
" can be provided to TypedDict, not both")
return cls.__class__(_typename, (), {'__annotations__': dict(fields)})


def NewType(name, tp):
"""NewType creates simple unique types with almost zero
runtime overhead. NewType(name, tp) is considered a subtype of tp
Expand Down