Tauthon is a backwards-compatible fork of the Python 2.7.18 interpreter with new syntax, builtins, and libraries backported from Python 3.x. Python code and C-extensions targeting Python 2.7 or below are expected to run unmodified on Tauthon and produce the same output. But with Tauthon, that code can now use some of the new features from Python 3.x.
Virtualenv support is provided by an external plugin: virtualenv-tauthon.
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>>> def f(a:int, b:str) -> list: ... pass ... >>> f.__annotations__ {'a': <type 'int'>, 'b': <type 'str'>, 'return': <type 'list'>}
More info: PEP 3107
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>>> def f(a, *, b): ... pass ... >>> f(1, 2) Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: f() takes exactly 1 positional argument (2 given) >>> f(1, b=2) >>>
More info: PEP 3102
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>>> import types >>> @types.coroutine ... def delayed_print(): ... printme = yield ... print printme ... >>> async def main(): ... while True: ... await delayed_print() ... >>> coro = main() >>> coro.send(None) >>> coro.send("hello") hello >>> coro.send("there") there >>> coro.send("friend") friend
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>>> class MyList(list): ... def __repr__(self): ... return "MyList" + super().__repr__() ... >>> MyList(range(3)) MyList[0, 1, 2]
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>>> from collections import OrderedDict >>> class Meta(type): ... @staticmethod ... def __prepare__(name, bases, **kwds): ... return OrderedDict() ... def __new__(cls, name, bases, namespace, **kwds): ... namespace.update(kwds) ... res = type.__new__(cls, name, bases, dict(namespace)) ... res._namespace = namespace ... return res ... def __init__(*args, **kwds): ... pass ... >>> class MyClass(metaclass=Meta, foo="bar"): ... def first(self): pass ... def second(self): pass ... def third(self): pass ... >>> MyClass.foo 'bar' >>> MyClass._namespace OrderedDict([('__module__', '__main__'), ('first', <function first at 0x1007ef568>), ('second', <function second at 0x10131b060>), ('third', <function third at 0x10131b118>), ('foo', 'bar')])
More info: PEP 3115, Introduction to Metaclasses (in Python 2.x), API Docs (Python 3.x)
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>>> x = 0 >>> def f(): ... x = 1 ... def g(): ... nonlocal x ... x = 2 ... print x ... g() ... print x ... >>> print x; f(); print x 0 1 2 0 >>> nonlocal = True; print nonlocal True
Caveat: As you can see, to maintain backwards compatibility nonlocal is not a keyword, unlike in Python 3.x. So it can still be used as an identifier.
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>>> def generator(): ... yield from range(3) ... yield from ['a', 'b', 'c'] ... >>> [x for x in generator()] [0, 1, 2, 'a', 'b', 'c']
More info: PEP 380
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>>> from typing import List, Dict >>> List[Dict[str, int]] typing.List[typing.Dict[str, int]] >>> def wordcount(words:List[str]) -> Dict[str, int]: ... return collections.Counter(words)
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>>> import inspect >>> def f(a:int, b, *args, c:str="foo", **kwds) -> list: pass ... >>> inspect.signature(f) <Signature (a:int, b, *args, c:str='foo', **kwds) -> list> >>> inspect.signature(f).parameters['c'].default 'foo'
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>>> import numpy as np >>> class Matrix(np.matrix): ... def __matmul__(self, other): ... return np.dot(self, other) ... >>> X = Matrix([[1, 2], [3, 4]]) >>> Y = Matrix([[4, 3], [2, 1]]) >>> print X [[1 2] [3 4]] >>> print Y [[4 3] [2 1]] >>> print X @ Y [[ 8 5] [20 13]] >>> X @= Y >>> X matrix([[ 8, 5], [20, 13]])
More info: PEP 465
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>>> open("not a file") Traceback (most recent call last): File "<stdin>", line 1, in <module> IOError: [Errno 2] No such file or directory: 'not a file' >>> try: ... open("not a file") ... except FileNotFoundError: ... pass ... >>>
Caveat: As you can see from the example, to maintain full backwards compatibility Tauthon does not raise these new OSErrors. Rather it gives you fine-grained OSErrors that you can catch them with, as an alternative to checking errno.
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>>> 1_234_567 1234567 >>> 0xBEEF_CAFE 3203386110 >>> 0b1111_0000 240 >>>
More info: PEP 515
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>>> from concurrent.futures import ThreadPoolExecutor >>> from datetime import datetime >>> import time >>> def snooze(seconds): ... print "It's now %s, snoozing for %d seconds." % (datetime.now(), seconds) ... time.sleep(seconds) ... print "BEEP BEEP BEEP it's %s, time to get up!" % datetime.now() ... >>> def snooze_again(future): ... print "Going back to sleep" ... snooze(3) ... >>> pool = ThreadPoolExecutor() >>> future = pool.submit(snooze, 60) It's now 2016-11-17 12:09:41.822658, snoozing for 60 seconds. >>> print future <Future at 0x1040b7b10 state=running> >>> future.add_done_callback(snooze_again) >>> print datetime.now() 2016-11-17 12:10:11.189143 >>> BEEP BEEP BEEP it's 2016-11-17 12:10:41.824054, time to get up! Going back to sleep It's now 2016-11-17 12:10:41.824206, snoozing for 3 seconds. BEEP BEEP BEEP it's 2016-11-17 12:10:44.829196, time to get up!
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>>> import types >>> original = {'a': 1} >>> read_only_view = types.MappingProxyType(original) >>> read_only_view['a'] 1 >>> read_only_view['b'] = 2 Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: 'dict_proxy' object does not support item assignment >>> original['c'] = 3 >>> original {'a': 1, 'c': 3} >>> read_only_view['c'] 3
More info: API Docs
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>>> import selectors
More info: API Docs
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More info: PEP 3120
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More info: PEP 418
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More info: BPO 5845
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More info: PR #128
Linux:
$ ./configure
$ make
OSX:
$ brew install openssl xz
$ CPPFLAGS="-I$(brew --prefix openssl)/include" LDFLAGS="-L$(brew --prefix openssl)/lib" MACOSX_DEPLOYMENT_TARGET=10.6 ./configure
$ make
You can then run Tauthon with ./tauthon or ./tauthon.exe.
Install with
$ make install
There are a small handful of backwards incompatibilities introduced by Tauthon. Triggering these involves checking the Python version, introspection of Python internals (including the AST), or depending on errors being raised from nonexistent new features.
Tauthon is licensed under the Python Software License, (see the LICENSE file for details). This is not an official Python release; see PEP 404.