TextWrapper fails to split 'two-and-a-half-hour' correctly

[samwyse]

BPO	25760
Nosy	@serhiy-storchaka

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2015-11-29.06:20:55.852>
created_at = <Date 2015-11-29.02:07:24.100>
labels = ['type-bug', 'library']
title = "TextWrapper fails to split 'two-and-a-half-hour' correctly"
updated_at = <Date 2015-11-29.06:20:55.834>
user = 'https://bugs.python.org/samwyse'

bugs.python.org fields:

activity = <Date 2015-11-29.06:20:55.834>
actor = 'serhiy.storchaka'
assignee = 'none'
closed = True
closed_date = <Date 2015-11-29.06:20:55.852>
closer = 'serhiy.storchaka'
components = ['Library (Lib)']
creation = <Date 2015-11-29.02:07:24.100>
creator = 'samwyse'
dependencies = []
files = []
hgrepos = []
issue_num = 25760
keywords = []
message_count = 2.0
messages = ['255558', '255561']
nosy_count = 2.0
nosy_names = ['samwyse', 'serhiy.storchaka']
pr_nums = []
priority = 'normal'
resolution = 'out of date'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue25760'
versions = ['Python 2.7', 'Python 3.2', 'Python 3.3', 'Python 3.4']

[samwyse]

Single character words in a hyphenated phrase are not split correctly. The root issue it the wordsep_re class variable. To reproduce, run the following:

>>> import textwrap
>>> textwrap.TextWrapper.wordsep_re.split('two-and-a-half-hour')
['', 'two-', 'and-a', '-half-', 'hour']

It works if 'a' is replaces with two or more alphabetic characters.

>>> textwrap.TextWrapper.wordsep_re.split('two-and-aa-half-hour')
['', 'two-', '', 'and-', '', 'aa-', '', 'half-', 'hour']

The problem is in this part of the pattern: (?=\w+[^0-9\\W])

I confess that I don't understand the situation that would require that complicated of a pattern. Why wouldn't (?=\w) would work?

[serhiy-storchaka]

Already fixed in bpo-22687.