hierarchical regular expression

[ottrey]

BPO	1174589
Nosy	@loewis

^{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 2005-04-05.00:00:58.000>
created_at = <Date 2005-04-01.03:59:41.000>
labels = ['library']
title = 'hierarchical regular expression'
updated_at = <Date 2005-04-05.00:00:58.000>
user = 'https://bugs.python.org/ottrey'

bugs.python.org fields:

activity = <Date 2005-04-05.00:00:58.000>
actor = 'loewis'
assignee = 'none'
closed = True
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2005-04-01.03:59:41.000>
creator = 'ottrey'
dependencies = []
files = []
hgrepos = []
issue_num = 1174589
keywords = ['patch']
message_count = 6.0
messages = ['48105', '48106', '48107', '48108', '48109', '48110']
nosy_count = 2.0
nosy_names = ['loewis', 'ottrey']
pr_nums = []
priority = 'normal'
resolution = 'rejected'
stage = None
status = 'closed'
superseder = None
type = None
url = 'https://bugs.python.org/issue1174589'
versions = []

[ottrey]

( from the re2 sourceforge project
http://pyre2.sourceforge.net )

The re2 library provides a hierarchical regular
expression extension to the re library.

re2 extracts a hierarchy of named groups from a string,
rather than the flat, incomplete dictionary that the
standard re module returns.

>>> import re
>>> buf='12 drummers drumming, 11 pipers piping, 10
lords a-leaping'
>>> regex='^((?P<verse>(?P<number>\d+)
(?P<activity>[^,]+))(, )?)*$'
>>> pat1=re.compile(regex)
>>> m=pat1.match(buf)
>>> m.groupdict()
{'verse': '10 lords a-leaping', 'number': '10',
'activity': 'lords a-leaping'}

>>> import re2
>>> buf='12 drummers drumming, 11 pipers piping, 10
lords a-leaping'
>>> regex='^((?P<verse>(?P<number>\d+)
(?P<activity>[^,]+))(, )?)*$'
>>> pat2=re2.compile(regex)
>>> x=pat2.extract(buf)
>>> x
{'verse': [{'number': '12', 'activity': 'drummers
drumming'}, {'number': '11', 'activity': 'pipers
piping'}, {'number': '10', 'activity': 'lords a-leaping'}]}

(See http://pyre2.sourceforge.net/ for more details.)

[loewis]

Logged In: YES
user_id=21627

Is this a patch? If so, where is the code, and are you its
author?

[ottrey]

Logged In: YES
user_id=609576

Sorry, it's more an extension than a patch.
(Although maybe it could be applied as a patch to the re
library.)
(BTW Where is the correct place to submit extensions?)

The code is in this subversion repository:
http://pintje.servebeer.com/svn/pyre2/trunk/

Or available for download here:
http://sourceforge.net/project/showfiles.php?group_id=134583

And has a development wiki here:
http://py.redsoft.be/pyre2/wiki/

And yes, I'm the author.

[loewis]

Logged In: YES
user_id=21627

We accept extensions only by means of patches. So you would
create a patch (as a unified or context diff) for the
current CVS;for completely new files, providing a tar ball
is also reasonable. I expect that you don't suggest literal
inclusion of the svn trunk directory into the dist/src
directory of the Python distribution.

However, in the specific case, I think whether or not the
new functionality should be added to Python at all probably
needs discussion. I recommend to ask on python-dev; be
prepared to write a PEP. As a starting point, I'm personally
concerned to have a module named "re2" in the standard
library. This will cause confusion to the users; it might be
better to merge the functionality into the re module.

[ottrey]

Logged In: YES
user_id=609576

Ok.
I'll ask on python-dev then.

[loewis]

Logged In: YES
user_id=21627

Given the discussion of python-dev, it appears that you want
to rework the code and come back if you have something
you'ld like to contribute. So I'm rejecting this patch for
now; please open a new one when you are ready (but likely,
you'ld write a PEP first, anyhow).