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diff --git a/docs/differences/python_38.rst b/docs/differences/python_38.rst new file mode 100644 index 000000000..47840a8b4 --- /dev/null +++ b/docs/differences/python_38.rst @@ -0,0 +1,118 @@ +.. _python_38: + +Python 3.8 +========== + +Python 3.8.0 (final) was released on the 14 October 2019. The Features for 3.8 +are defined in `PEP 569 <https://www.python.org/dev/peps/pep-0569/#id9>`_ and +a detailed description of the changes can be found in What's New in `Python +3.8. <https://docs.python.org/3/whatsnew/3.8.html>`_ + + +--------------------------------------------------------+---------------------------------------------------+---------------+ + | **Features:** | Status | + +--------------------------------------------------------+---------------------------------------------------+---------------+ + | `PEP 570 <https://www.python.org/dev/peps/pep-0570/>`_ | Positional-only arguments | | + +--------------------------------------------------------+---------------------------------------------------+---------------+ + | `PEP 572 <https://www.python.org/dev/peps/pep-0572/>`_ | Assignment Expressions | | + +--------------------------------------------------------+---------------------------------------------------+---------------+ + | `PEP 574 <https://www.python.org/dev/peps/pep-0574/>`_ | Pickle protocol 5 with out-of-band data | | + +--------------------------------------------------------+---------------------------------------------------+---------------+ + | `PEP 578 <https://www.python.org/dev/peps/pep-0578/>`_ | Runtime audit hooks | | + +--------------------------------------------------------+---------------------------------------------------+---------------+ + | `PEP 587 <https://www.python.org/dev/peps/pep-0587/>`_ | Python Initialization Configuration | | + +--------------------------------------------------------+---------------------------------------------------+---------------+ + | `PEP 590 <https://www.python.org/dev/peps/pep-0590/>`_ | Vectorcall: a fast calling protocol for CPython | | + +--------------------------------------------------------+---------------------------------------------------+---------------+ + | **Miscellaneous** | + +------------------------------------------------------------------------------------------------------------+---------------+ + | f-strings support = for self-documenting expressions and debugging | Completed | + +------------------------------------------------------------------------------------------------------------+---------------+ + +Other Language Changes: + + +------------------------------------------------------------------------------------------------------------+-------------+ + | A *continue* statement was illegal in the *finally* clause due to a problem with the implementation. In | Completed | + | Python 3.8 this restriction was lifted | | + +------------------------------------------------------------------------------------------------------------+-------------+ + | The *bool*, *int* , and *fractions.Fraction* types now have an *as_integer_ratio()* method like that found | | + | in *float* and *decimal.Decimal* | | + +------------------------------------------------------------------------------------------------------------+-------------+ + | Constructors of *int*, *float* and *complex* will now use the *__index__()* special method, if available | | + | and the corresponding method *__int__()*, *__float__()* or *__complex__()* is not available | | + +------------------------------------------------------------------------------------------------------------+-------------+ + | Added support of *\N{name}* escapes in regular expressions | | + +------------------------------------------------------------------------------------------------------------+-------------+ + | Dict and dictviews are now iterable in reversed insertion order using *reversed()* | | + +------------------------------------------------------------------------------------------------------------+-------------+ + | The syntax allowed for keyword names in function calls was further restricted. In particular, | | + | f((keyword)=arg) is no longer allowed | | + +------------------------------------------------------------------------------------------------------------+-------------+ + | Generalized iterable unpacking in yield and return statements no longer requires enclosing parentheses | | + +------------------------------------------------------------------------------------------------------------+-------------+ + | When a comma is missed in code such as [(10, 20) (30, 40)], the compiler displays a SyntaxWarning with a | | + | helpful suggestion | | + +------------------------------------------------------------------------------------------------------------+-------------+ + | Arithmetic operations between subclasses of *datetime.date* or *datetime.datetime* and *datetime.timedelta*| | + | objects now return an instance of the subclass, rather than the base class | | + +------------------------------------------------------------------------------------------------------------+-------------+ + | When the Python interpreter is interrupted by *Ctrl-C (SIGINT)* and the resulting *KeyboardInterrupt* | | + | exception is not caught, the Python process now exits via a SIGINT signal or with the correct exit code | | + | such that the calling process can detect that it died due to a *Ctrl-C* | | + +------------------------------------------------------------------------------------------------------------+-------------+ + | Some advanced styles of programming require updating the *types.CodeType* object for an existing function | | + +------------------------------------------------------------------------------------------------------------+-------------+ + | For integers, the three-argument form of the pow() function now permits the exponent to be negative in the | | + | case where the base is relatively prime to the modulus | | + +------------------------------------------------------------------------------------------------------------+-------------+ + | Dict comprehensions have been synced-up with dict literals so that the key is computed first and the value | | + | second | | + +------------------------------------------------------------------------------------------------------------+-------------+ + | The *object.__reduce__()* method can now return a tuple from two to six elements long | | + +------------------------------------------------------------------------------------------------------------+-------------+ + +Changes to built-in modules: + + +------------------------------------------------------------------------------------------------------------+-------------+ + | `asyncio` | + +------------------------------------------------------------------------------------------------------------+-------------+ + | *asyncio.run()* has graduated from the provisional to stable API | Completed | + +------------------------------------------------------------------------------------------------------------+-------------+ + | Running *python -m asyncio* launches a natively async REPL | | + +------------------------------------------------------------------------------------------------------------+-------------+ + | The exception *asyncio.CancelledError* now inherits from *BaseException* rather than *Exception* and no | Completed | + | longer inherits from *concurrent.futures.CancelledError* | | + +------------------------------------------------------------------------------------------------------------+-------------+ + | Added *asyncio.Task.get_coro()* for getting the wrapped coroutine within an *asyncio.Task* | | + +------------------------------------------------------------------------------------------------------------+-------------+ + | Asyncio tasks can now be named, either by passing the name keyword argument to *asyncio.create_task()* or | | + | the *create_task()* event loop method, or by calling the *set_name()* method on the task object | | + +------------------------------------------------------------------------------------------------------------+-------------+ + | Added support for Happy Eyeballs to *asyncio.loop.create_connection()*. To specify the behavior, two new | | + | parameters have been added: *happy_eyeballs_delay* and interleave. | | + +------------------------------------------------------------------------------------------------------------+-------------+ + | `gc` | + +------------------------------------------------------------------------------------------------------------+-------------+ + | *get_objects()* can now receive an optional generation parameter indicating a generation to get objects | | + | from. (Note, though, that while *gc* is a built-in, *get_objects()* is not implemented for MicroPython) | | + +------------------------------------------------------------------------------------------------------------+-------------+ + | `math` | + +------------------------------------------------------------------------------------------------------------+-------------+ + | Added new function *math.dist()* for computing Euclidean distance between two points | | + +------------------------------------------------------------------------------------------------------------+-------------+ + | Expanded the *math.hypot()* function to handle multiple dimensions | | + +------------------------------------------------------------------------------------------------------------+-------------+ + | Added new function, *math.prod()*, as analogous function to *sum()* that returns the product of a "start" | | + | value (default: 1) times an iterable of numbers | | + +------------------------------------------------------------------------------------------------------------+-------------+ + | Added two new combinatoric functions *math.perm()* and *math.comb()* | | + +------------------------------------------------------------------------------------------------------------+-------------+ + | Added a new function *math.isqrt()* for computing accurate integer square roots without conversion to | | + | floating point | | + +------------------------------------------------------------------------------------------------------------+-------------+ + | The function *math.factorial()* no longer accepts arguments that are not int-like | Completed | + +------------------------------------------------------------------------------------------------------------+-------------+ + | `sys` | + +------------------------------------------------------------------------------------------------------------+-------------+ + | Add new *sys.unraisablehook()* function which can be overridden to control how "unraisable exceptions" | | + | are handled | | + +------------------------------------------------------------------------------------------------------------+-------------+ |