Tauthon: Fork of Python 2.7 with new syntax, builtins, libraries from Python 3

栏目: IT技术 · 发布时间: 4年前

内容简介:Tauthon is a backwards-compatible fork of the Python 2.7.17 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 th

Tauthon

Tauthon is a backwards-compatible fork of the Python 2.7.17 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.

What's new in Tauthon

  • Function Annotations

    >>> def f(a:int, b:str) -> list:
    ...     pass
    ...
    >>> f.__annotations__
    {'a': <type 'int'>, 'b': <type 'str'>, 'return': <type 'list'>}

    More info: PEP 3107

  • Keyword-Only Arguments

    >>> 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

  • "async" and "await" Syntax

    >>> 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

    More info: PEP 492 , Tutorial

  • Argument-less "super"

    >>> class MyList(list):
    ...     def __repr__(self):
    ...             return "MyList" + super().__repr__()
    ...
    >>> MyList(range(3))
    MyList[0, 1, 2]

    More info: PEP 3135 , API Docs

  • New Metaclass Syntax

    >>> 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)

  • "nonlocal"

    >>> 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.

    More info: PEP 3104 , API Docs

  • "yield from" Syntax

    >>> 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

  • "typing" Module

    >>> 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)

    More info: PEP 483 , PEP 484 , API Docs

  • Function Signatures in "inspect"

    >>> 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'

    More info: PEP 362 , API Docs

  • Matrix Multiplication Operator

    >>> 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

  • Fine-grained OSErrors

    >>> 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.

    More info: PEP 3151 , API Docs

  • Underscores in Numeric Literals

    >>> 1_234_567
    1234567
    >>> 0xBEEF_CAFE
    3203386110
    >>> 0b1111_0000
    240
    >>>

    More info: PEP 515

  • "concurrent.futures" Module

    >>> 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!

    More info: PEP 3148 , API Docs

  • "types.MappingProxyType"

    >>> 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

  • "selectors" Module

    >>> import selectors

    More info: API Docs

  • UTF-8 as the default source encoding

    More info: PEP 3120

  • monotonic time, performance counter, and process time functions

    More info: PEP 418

  • tab completion enabled by default in the interactive interpreter

    More info: BPO 5845

Building and Installation

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

Backwards-incompatibilities

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.

License

Tauthon is licensed under the Python Software License, (see the LICENSE file for details). This is not an official Python release; see PEP 404 .


以上就是本文的全部内容,希望本文的内容对大家的学习或者工作能带来一定的帮助,也希望大家多多支持 码农网

查看所有标签

猜你喜欢:

本站部分资源来源于网络,本站转载出于传递更多信息之目的,版权归原作者或者来源机构所有,如转载稿涉及版权问题,请联系我们

运营之光

运营之光

黄有璨 / 电子工业出版社 / 2016-9-1 / 59.00元

在互联网行业内,“运营”这个职能发展到一定阶段后,往往更需要有成熟的知识体系和工作方法来给予行业从业者们以指引。 《运营之光:我的互联网运营方法论与自白》尤其难得之处在于:它既对“什么是运营”这样的概念认知类问题进行了解读,又带有大量实际的工作技巧、工作思维和工作方法,还包含了很多对于运营的思考、宏观分析和建议,可谓内容完整而全面,同时书中加入了作者亲历的大量真实案例,让全书读起来深入浅出、......一起来看看 《运营之光》 这本书的介绍吧!

SHA 加密
SHA 加密

SHA 加密工具

XML、JSON 在线转换
XML、JSON 在线转换

在线XML、JSON转换工具