01953f2964
And how they relate to MicroPython. As these features are implemented (or the decision is made to not implement them) the tables can be updated to document the differences between MicroPython and standard Python.
119 lines
13 KiB
ReStructuredText
119 lines
13 KiB
ReStructuredText
.. _python_38:
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Python 3.8
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==========
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Python 3.8.0 (final) was released on the 14 October 2019. The Features for 3.8
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are defined in `PEP 569 <https://www.python.org/dev/peps/pep-0569/#id9>`_ and
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a detailed description of the changes can be found in What's New in `Python
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3.8. <https://docs.python.org/3/whatsnew/3.8.html>`_
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+--------------------------------------------------------+---------------------------------------------------+---------------+
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| **Features:** | Status |
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+--------------------------------------------------------+---------------------------------------------------+---------------+
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| `PEP 570 <https://www.python.org/dev/peps/pep-0570/>`_ | Positional-only arguments | |
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+--------------------------------------------------------+---------------------------------------------------+---------------+
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| `PEP 572 <https://www.python.org/dev/peps/pep-0572/>`_ | Assignment Expressions | |
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+--------------------------------------------------------+---------------------------------------------------+---------------+
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| `PEP 574 <https://www.python.org/dev/peps/pep-0574/>`_ | Pickle protocol 5 with out-of-band data | |
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+--------------------------------------------------------+---------------------------------------------------+---------------+
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| `PEP 578 <https://www.python.org/dev/peps/pep-0578/>`_ | Runtime audit hooks | |
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+--------------------------------------------------------+---------------------------------------------------+---------------+
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| `PEP 587 <https://www.python.org/dev/peps/pep-0587/>`_ | Python Initialization Configuration | |
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+--------------------------------------------------------+---------------------------------------------------+---------------+
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| `PEP 590 <https://www.python.org/dev/peps/pep-0590/>`_ | Vectorcall: a fast calling protocol for CPython | |
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+--------------------------------------------------------+---------------------------------------------------+---------------+
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| **Miscellaneous** |
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+------------------------------------------------------------------------------------------------------------+---------------+
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| f-strings support = for self-documenting expressions and debugging | Completed |
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+------------------------------------------------------------------------------------------------------------+---------------+
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Other Language Changes:
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+------------------------------------------------------------------------------------------------------------+-------------+
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| A *continue* statement was illegal in the *finally* clause due to a problem with the implementation. In | Completed |
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| Python 3.8 this restriction was lifted | |
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+------------------------------------------------------------------------------------------------------------+-------------+
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| The *bool*, *int* , and *fractions.Fraction* types now have an *as_integer_ratio()* method like that found | |
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| in *float* and *decimal.Decimal* | |
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+------------------------------------------------------------------------------------------------------------+-------------+
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| Constructors of *int*, *float* and *complex* will now use the *__index__()* special method, if available | |
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| and the corresponding method *__int__()*, *__float__()* or *__complex__()* is not available | |
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+------------------------------------------------------------------------------------------------------------+-------------+
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| Added support of *\N{name}* escapes in regular expressions | |
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+------------------------------------------------------------------------------------------------------------+-------------+
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| Dict and dictviews are now iterable in reversed insertion order using *reversed()* | |
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+------------------------------------------------------------------------------------------------------------+-------------+
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| The syntax allowed for keyword names in function calls was further restricted. In particular, | |
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| f((keyword)=arg) is no longer allowed | |
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+------------------------------------------------------------------------------------------------------------+-------------+
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| Generalized iterable unpacking in yield and return statements no longer requires enclosing parentheses | |
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+------------------------------------------------------------------------------------------------------------+-------------+
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| When a comma is missed in code such as [(10, 20) (30, 40)], the compiler displays a SyntaxWarning with a | |
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| helpful suggestion | |
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+------------------------------------------------------------------------------------------------------------+-------------+
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| Arithmetic operations between subclasses of *datetime.date* or *datetime.datetime* and *datetime.timedelta*| |
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| objects now return an instance of the subclass, rather than the base class | |
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+------------------------------------------------------------------------------------------------------------+-------------+
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| When the Python interpreter is interrupted by *Ctrl-C (SIGINT)* and the resulting *KeyboardInterrupt* | |
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| exception is not caught, the Python process now exits via a SIGINT signal or with the correct exit code | |
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| such that the calling process can detect that it died due to a *Ctrl-C* | |
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+------------------------------------------------------------------------------------------------------------+-------------+
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| Some advanced styles of programming require updating the *types.CodeType* object for an existing function | |
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+------------------------------------------------------------------------------------------------------------+-------------+
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| For integers, the three-argument form of the pow() function now permits the exponent to be negative in the | |
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| case where the base is relatively prime to the modulus | |
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+------------------------------------------------------------------------------------------------------------+-------------+
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| Dict comprehensions have been synced-up with dict literals so that the key is computed first and the value | |
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| second | |
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+------------------------------------------------------------------------------------------------------------+-------------+
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| The *object.__reduce__()* method can now return a tuple from two to six elements long | |
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+------------------------------------------------------------------------------------------------------------+-------------+
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Changes to built-in modules:
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+------------------------------------------------------------------------------------------------------------+-------------+
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| `asyncio` |
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+------------------------------------------------------------------------------------------------------------+-------------+
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| *asyncio.run()* has graduated from the provisional to stable API | Completed |
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+------------------------------------------------------------------------------------------------------------+-------------+
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| Running *python -m asyncio* launches a natively async REPL | |
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+------------------------------------------------------------------------------------------------------------+-------------+
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| The exception *asyncio.CancelledError* now inherits from *BaseException* rather than *Exception* and no | Completed |
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| longer inherits from *concurrent.futures.CancelledError* | |
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+------------------------------------------------------------------------------------------------------------+-------------+
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| Added *asyncio.Task.get_coro()* for getting the wrapped coroutine within an *asyncio.Task* | |
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+------------------------------------------------------------------------------------------------------------+-------------+
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| Asyncio tasks can now be named, either by passing the name keyword argument to *asyncio.create_task()* or | |
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| the *create_task()* event loop method, or by calling the *set_name()* method on the task object | |
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+------------------------------------------------------------------------------------------------------------+-------------+
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| Added support for Happy Eyeballs to *asyncio.loop.create_connection()*. To specify the behavior, two new | |
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| parameters have been added: *happy_eyeballs_delay* and interleave. | |
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+------------------------------------------------------------------------------------------------------------+-------------+
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| `gc` |
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+------------------------------------------------------------------------------------------------------------+-------------+
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| *get_objects()* can now receive an optional generation parameter indicating a generation to get objects | |
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| from. (Note, though, that while *gc* is a built-in, *get_objects()* is not implemented for MicroPython) | |
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+------------------------------------------------------------------------------------------------------------+-------------+
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| `math` |
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+------------------------------------------------------------------------------------------------------------+-------------+
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| Added new function *math.dist()* for computing Euclidean distance between two points | |
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+------------------------------------------------------------------------------------------------------------+-------------+
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| Expanded the *math.hypot()* function to handle multiple dimensions | |
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+------------------------------------------------------------------------------------------------------------+-------------+
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| Added new function, *math.prod()*, as analogous function to *sum()* that returns the product of a "start" | |
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| value (default: 1) times an iterable of numbers | |
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+------------------------------------------------------------------------------------------------------------+-------------+
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| Added two new combinatoric functions *math.perm()* and *math.comb()* | |
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+------------------------------------------------------------------------------------------------------------+-------------+
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| Added a new function *math.isqrt()* for computing accurate integer square roots without conversion to | |
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| floating point | |
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+------------------------------------------------------------------------------------------------------------+-------------+
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| The function *math.factorial()* no longer accepts arguments that are not int-like | Completed |
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+------------------------------------------------------------------------------------------------------------+-------------+
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| `sys` |
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+------------------------------------------------------------------------------------------------------------+-------------+
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| Add new *sys.unraisablehook()* function which can be overridden to control how "unraisable exceptions" | |
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| are handled | |
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+------------------------------------------------------------------------------------------------------------+-------------+
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