Home - News ( United States | United Kingdom | Italy | Germany ) - Football scores

Showing content from https://www.python.org/dev/peps/pep-0623/ below:

PEP 623 – Remove wstr from Unicode

Author:

Inada Naoki <songofacandy at gmail.com>

BDFL-Delegate:

Victor Stinner <vstinner at python.org>

Discussions-To:

Python-Dev thread

Status:

Final

Type:

Standards Track

Created:

25-Jun-2020

Python-Version:

3.10

Resolution:

Python-Dev thread

• Abstract
• Motivation
  • Memory usage
  • Runtime overhead
  • Simplicity
• Rationale
  • Python 4.0 is not scheduled yet
  • Python 2 reached EOL
• Plan
  • Python 3.9
  • Python 3.10
  • Python 3.12
• Discussion
• References
• Copyright

PEP 393 deprecated some unicode APIs, and introduced wchar_t *wstr, and Py_ssize_t wstr_length in the Unicode structure to support these deprecated APIs.

This PEP is planning removal of wstr, and wstr_length with deprecated APIs using these members by Python 3.12.

Deprecated APIs which doesn’t use the members are out of scope because they can be removed independently.

str is one of the most used types in Python. Even most simple ASCII strings have a wstr member. It consumes 8 bytes per string on 64-bit systems.

To support legacy Unicode object, many Unicode APIs must call PyUnicode_READY().

We can remove this overhead too by dropping support of legacy Unicode object.

Supporting legacy Unicode object makes the Unicode implementation more complex. Until we drop legacy Unicode object, it is very hard to try other Unicode implementation like UTF-8 based implementation in PyPy.

PEP 393 introduced efficient internal representation of Unicode and removed border between “narrow” and “wide” build of Python.

PEP 393 was implemented in Python 3.3 which is released in 2012. Old APIs were deprecated since then, and the removal was scheduled in Python 4.0.

Python 4.0 was expected as next version of Python 3.9 when PEP 393 was accepted. But the next version of Python 3.9 is Python 3.10, not 4.0. This is why this PEP schedule the removal plan again.

Since Python 2 didn’t have PEP 393 Unicode implementation, legacy APIs might help C extension modules supporting both of Python 2 and 3.

But Python 2 reached the EOL in 2020. We can remove legacy APIs kept for compatibility with Python 2.

These macros and functions are marked as deprecated, using Py_DEPRECATED macro.

• Py_UNICODE_WSTR_LENGTH()
• PyUnicode_GET_SIZE()
• PyUnicode_GetSize()
• PyUnicode_GET_DATA_SIZE()
• PyUnicode_AS_UNICODE()
• PyUnicode_AS_DATA()
• PyUnicode_AsUnicode()
• _PyUnicode_AsUnicode()
• PyUnicode_AsUnicodeAndSize()
• PyUnicode_FromUnicode()

• Following macros, enum members are marked as deprecated. Py_DEPRECATED(3.10) macro are used as possible. But they are deprecated only in comment and document if the macro can not be used easily.
  • PyUnicode_WCHAR_KIND
  • PyUnicode_READY()
  • PyUnicode_IS_READY()
  • PyUnicode_IS_COMPACT()
• PyUnicode_FromUnicode(NULL, size) and PyUnicode_FromStringAndSize(NULL, size) emit DeprecationWarning when size > 0.
• PyArg_ParseTuple() and PyArg_ParseTupleAndKeywords() emit DeprecationWarning when u, u#, Z, and Z# formats are used.

• Following members are removed from the Unicode structures:
  • wstr
  • wstr_length
  • state.compact
  • state.ready
• The PyUnicodeObject structure is removed.
• Following macros and functions, and enum members are removed:
  • Py_UNICODE_WSTR_LENGTH()
  • PyUnicode_GET_SIZE()
  • PyUnicode_GetSize()
  • PyUnicode_GET_DATA_SIZE()
  • PyUnicode_AS_UNICODE()
  • PyUnicode_AS_DATA()
  • PyUnicode_AsUnicode()
  • _PyUnicode_AsUnicode()
  • PyUnicode_AsUnicodeAndSize()
  • PyUnicode_FromUnicode()
  • PyUnicode_WCHAR_KIND
  • PyUnicode_READY()
  • PyUnicode_IS_READY()
  • PyUnicode_IS_COMPACT()
• PyUnicode_FromStringAndSize(NULL, size)) raises RuntimeError when size > 0.
• PyArg_ParseTuple() and PyArg_ParseTupleAndKeywords() raise SystemError when u, u#, Z, and Z# formats are used, as other unsupported format character.

• Draft PEP: Remove wstr from Unicode
• When can we remove wchar_t* cache from string?
• PEP 623: Remove wstr from Unicode object #1462

• bpo-38604: Schedule Py_UNICODE API removal
• bpo-36346: Prepare for removing the legacy Unicode C API
• bpo-30863: Rewrite PyUnicode_AsWideChar() and PyUnicode_AsWideCharString(): They no longer cache the wchar_t* representation of string objects.

This document has been placed in the public domain.

RetroSearch is an open source project built by @garambo | Open a GitHub Issue

Search and Browse the WWW like it's 1997 | Search results from DuckDuckGo

HTML: 3.2 | Encoding: UTF-8 | Version: 0.7.4