loongson/pypi/: wcwidth-0.2.5 metadata and description

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Measures the displayed width of unicode strings in a terminal

author Jeff Quast
author_email contact@jeffquast.com
classifiers
  • Intended Audience :: Developers
  • Natural Language :: English
  • Development Status :: 5 - Production/Stable
  • Environment :: Console
  • License :: OSI Approved :: MIT License
  • Operating System :: POSIX
  • Programming Language :: Python :: 2.7
  • Programming Language :: Python :: 3.5
  • Programming Language :: Python :: 3.6
  • Programming Language :: Python :: 3.7
  • Programming Language :: Python :: 3.8
  • Topic :: Software Development :: Libraries
  • Topic :: Software Development :: Localization
  • Topic :: Software Development :: Internationalization
  • Topic :: Terminals
keywords cjk,combining,console,eastasian,emojiemulator,terminal,unicode,wcswidth,wcwidth,xterm
license MIT
requires_dist
  • backports.functools-lru-cache (>=1.2.1) ; python_version < "3.2"

Because this project isn't in the mirror_whitelist, no releases from root/pypi are included.

File Tox results History
wcwidth-0.2.5-py2.py3-none-any.whl
Size
29 KB
Type
Python Wheel
Python
2.7

Downloads codecov.io Code Coverage MIT License

Introduction

This library is mainly for CLI programs that carefully produce output for Terminals, or make pretend to be an emulator.

Problem Statement: The printable length of most strings are equal to the number of cells they occupy on the screen 1 charater : 1 cell. However, there are categories of characters that occupy 2 cells (full-wide), and others that occupy 0 cells (zero-width).

Solution: POSIX.1-2001 and POSIX.1-2008 conforming systems provide wcwidth(3) and wcswidth(3) C functions of which this python module’s functions precisely copy. These functions return the number of cells a unicode string is expected to occupy.

Installation

The stable version of this package is maintained on pypi, install using pip:

pip install wcwidth

Example

Problem: given the following phrase (Japanese),

>>>  text = u'コンニチハ'

Python incorrectly uses the string length of 5 codepoints rather than the printible length of 10 cells, so that when using the rjust function, the output length is wrong:

>>> print(len('コンニチハ'))
5

>>> print('コンニチハ'.rjust(20, '_'))
_____コンニチハ

By defining our own “rjust” function that uses wcwidth, we can correct this:

>>> def wc_rjust(text, length, padding=' '):
...    from wcwidth import wcswidth
...    return padding * max(0, (length - wcswidth(text))) + text
...

Our Solution uses wcswidth to determine the string length correctly:

>>> from wcwidth import wcswidth
>>> print(wcswidth('コンニチハ'))
10

>>> print(wc_rjust('コンニチハ', 20, '_'))
__________コンニチハ

Choosing a Version

Export an environment variable, UNICODE_VERSION. This should be done by terminal emulators or those developers experimenting with authoring one of their own, from shell:

$ export UNICODE_VERSION=13.0

If unspecified, the latest version is used. If your Terminal Emulator does not export this variable, you can use the jquast/ucs-detect utility to automatically detect and export it to your shell.

wcwidth, wcswidth

Use function wcwidth() to determine the length of a single unicode character, and wcswidth() to determine the length of many, a string of unicode characters.

Briefly, return values of function wcwidth() are:

-1
Indeterminate (not printable).
0
Does not advance the cursor, such as NULL or Combining.
2
Characters of category East Asian Wide (W) or East Asian Full-width (F) which are displayed using two terminal cells.
1
All others.

Function wcswidth() simply returns the sum of all values for each character along a string, or -1 when it occurs anywhere along a string.

Full API Documentation at http://wcwidth.readthedocs.org

Developing

Install wcwidth in editable mode:

pip install -e.

Execute unit tests using tox:

tox

Regenerate python code tables from latest Unicode Specification data files:

tox -eupdate

Supplementary tools for browsing and testing terminals for wide unicode characters are found in the bin/ of this project’s source code. Just ensure to first pip install -erequirements-develop.txt from this projects main folder. For example, an interactive browser for testing:

./bin/wcwidth-browser.py

Uses

This library is used in:

Other Languages

History

0.2.0 2020-06-01
  • Enhancement: Unicode version may be selected by exporting the Environment variable UNICODE_VERSION, such as 13.0, or 6.3.0. See the jquast/ucs-detect CLI utility for automatic detection.
  • Enhancement: API Documentation is published to readthedocs.org.
  • Updated tables for all Unicode Specifications with files published in a programmatically consumable format, versions 4.1.0 through 13.0 that are published , versions
0.1.9 2020-03-22
  • Performance optimization by Avram Lubkin, PR #35.
  • Updated tables to Unicode Specification 13.0.0.
0.1.8 2020-01-01
  • Updated tables to Unicode Specification 12.0.0. (PR #30).
0.1.7 2016-07-01
  • Updated tables to Unicode Specification 9.0.0. (PR #18).
0.1.6 2016-01-08 Production/Stable
  • LICENSE file now included with distribution.
0.1.5 2015-09-13 Alpha
  • Bugfix: Resolution of “combining character width” issue, most especially those that previously returned -1 now often (correctly) return 0. resolved by Philip Craig via PR #11.
  • Deprecated: The module path wcwidth.table_comb is no longer available, it has been superseded by module path wcwidth.table_zero.
0.1.4 2014-11-20 Pre-Alpha
0.1.3 2014-10-29 Pre-Alpha
0.1.2 2014-10-28 Pre-Alpha
0.1.1 2014-05-14 Pre-Alpha
  • Initial release to pypi, Based on Unicode Specification 6.3.0

This code was originally derived directly from C code of the same name, whose latest version is available at http://www.cl.cam.ac.uk/~mgk25/ucs/wcwidth.c:

* Markus Kuhn -- 2007-05-26 (Unicode 5.0)
*
* Permission to use, copy, modify, and distribute this software
* for any purpose and without fee is hereby granted. The author
* disclaims all warranties with regard to this software.