El lun., 1 abr. 2019 a las 7:28, Antoine Pietri (<antoine.piet...@gmail.com>) escribió:
> While the switch to Python 3 did an excellent job in removing some of > the old inconsistencies we had in the language, pretty much everyone > agrees that some other backwards-incompatible changes could be made to > remove some old warts and bring even more consistency to Python. > > Since Python 4 is getting closer and closer, I think it’s time to > finally discuss some of the most obvious changes we should do for > Python 4. Here is the list I compiled: > > - The / operator returns floats, which loses information when both of > the operands are integer. In Python 4, “1 / 2” should return a > decimal.Decimal. To ease the transition, we propose to add a new “from > __future__ import decimal_division” in Python 3.9 to enable this > behavior. > More broadly, one of the best changes in Python 3 was the sanitization of the string/unicode logic: in Python 2 str and unicode were mostly-but-not-always interchangeable, but not always, and that led to a lot of hard to debug errors. Python 3 fixed this by separating the two more cleanly. Python 4 has the opportunity to do something similar to separate out another pair of easily confused types: int and float. Broadly speaking, we should use float for human-understandable numbers, and int for things that map directly to memory offsets in the computer, and we should avoid mixing them. This suggests the following changes: - int + float (and generally any mixed operation between ints and floats) should throw a TypeError - len() should return a float - list.__getitem__ should only accepts ints, not floats - integer overflow should use two's complement wraparound instead of infinite precision > - As most of the Python ecosystem is moving towards async, some of the > old I/O-blocking APIs should be progressively migrated to an async by > default model. The most obvious candidate to start this transition is > the print function, which blocks on the I/O of flushes. We propose to > make “print” an async coroutine. In Python 3.9, this feature could be > optionally enabled with “from __future__ import print_coroutine”. > - To ease compatibility with the Windows API, the PyUnicode* objects > should be internally represented as an array of uint16_t, as it would > avoid the conversion overhead from UCS. CPython migration details are > left as an exercise for the developer. > > We think more changes are obviously warranted (e.g adding a new string > formatting module, changing the semantic of the import system, using > := in with statements...), but these changes will need specific > threads of their own. > > So, can you think of other backward-incompatible changes that should > be done in Python 4? Don't hesitate to add your own ideas :-) > > Thanks, > > -- > Antoine Pietri > _______________________________________________ > Python-ideas mailing list > Python-ideas@python.org > https://mail.python.org/mailman/listinfo/python-ideas > Code of Conduct: http://python.org/psf/codeofconduct/ >
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