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SRE: Atomic Grouping (?>...) is not supported #34627

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effbot mannequin opened this issue Jun 14, 2001 · 13 comments
Closed

SRE: Atomic Grouping (?>...) is not supported #34627

effbot mannequin opened this issue Jun 14, 2001 · 13 comments
Labels
3.11 expert-regex stdlib Python modules in the Lib dir type-feature A feature request or enhancement

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@effbot
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Mannequin

effbot mannequin commented Jun 14, 2001

BPO 433030
Nosy @birkenfeld, @terryjreedy, @ezio-melotti, @serhiy-storchaka
PRs
  • bpo-433030: Add support of atomic grouping in regular expressions #31982
  • Files
  • issue2636-01.patch
  • re_atomic_groups.patch
  • 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 = None
    created_at = <Date 2001-06-14.08:30:56.000>
    labels = ['expert-regex', 'type-feature', 'library', '3.11']
    title = 'SRE: Atomic Grouping (?>...) is not supported'
    updated_at = <Date 2022-03-21.16:28:37.831>
    user = 'https://bugs.python.org/effbot'

    bugs.python.org fields:

    activity = <Date 2022-03-21.16:28:37.831>
    actor = 'serhiy.storchaka'
    assignee = 'none'
    closed = False
    closed_date = None
    closer = None
    components = ['Library (Lib)', 'Regular Expressions']
    creation = <Date 2001-06-14.08:30:56.000>
    creator = 'effbot'
    dependencies = []
    files = ['10646', '37182']
    hgrepos = []
    issue_num = 433030
    keywords = ['patch']
    message_count = 12.0
    messages = ['53164', '63284', '63288', '64634', '64735', '65777', '68337', '113201', '114621', '231041', '231049', '415685']
    nosy_count = 10.0
    nosy_names = ['effbot', 'georg.brandl', 'terry.reedy', 'rsc', 'timehorse', 'ezio.melotti', 'mrabarnett', 'THRlWiTi', 'abacabadabacaba', 'serhiy.storchaka']
    pr_nums = ['31982']
    priority = 'normal'
    resolution = None
    stage = 'patch review'
    status = 'open'
    superseder = None
    type = 'enhancement'
    url = 'https://bugs.python.org/issue433030'
    versions = ['Python 3.11']

    @effbot
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    effbot mannequin commented Jun 14, 2001

    from the jeffrey friedl report:

    (?>...) is not supported

    [this is a "stand-alone pattern". the engine has code
    for this, but the parser doesn't recognize this yet.
    shouldn't be too hard to fix; I just need a couple of
    good test cases before I start /F]

    @effbot effbot mannequin self-assigned this Jun 14, 2001
    @effbot effbot mannequin added expert-regex type-feature A feature request or enhancement labels Jun 14, 2001
    @effbot effbot mannequin self-assigned this Jun 14, 2001
    @effbot effbot mannequin added expert-regex type-feature A feature request or enhancement labels Jun 14, 2001
    @akuchling
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    akuchling commented Mar 5, 2008

    Also referred to as an atomic group: see
    http://www.regular-expressions.info/atomic.html for a discussion.

    Fredrik, when you say "the engine has code for this", what do you mean?

    @akuchling
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    akuchling commented Mar 5, 2008

    There's also an alternate syntax for this, called possessive
    quantifiers: a*+, a++, a{m,n}+.

    @timehorse
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    timehorse mannequin commented Mar 28, 2008

    Fredrik,

    If you're still listening, I am gonna try and tackle this one but I
    would like to know why you or the famous Jeffrey of the Regexp world
    claims that there is already code in the Regexp Engine for Atomic
    Grouping? Adding a hook for (?>...) should be trivial but I don't wanna
    re-invent the wheel if the proper stack-unwind code already exists.
    Thanks. Of course, Andrew (a.k.a. A.M. Kuchling) already asked this
    question and you did not answer it, so I guess you're not reading this,
    but if you are, please respond. Thanks!

    @timehorse timehorse mannequin changed the title SRE: (?>...) is not supported SRE: Atomic Grouping (?>...) is not supported Mar 28, 2008
    @timehorse timehorse mannequin changed the title SRE: (?>...) is not supported SRE: Atomic Grouping (?>...) is not supported Mar 28, 2008
    @timehorse
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    timehorse mannequin commented Mar 29, 2008

    I'm digging into the sre_parse.py at the moment and this I have all the
    changes I need for that now. The rest of the changes I believe are in
    either sre_compile.py or more likely directly in _sre.c, so I will
    examine those files next. I am attaching a single diff for
    expedience. This is not an official patch, just a sample to see the
    progress I am making. I forgot the correct format for patch files but
    I promise to get it right when I have made more progress.

    @timehorse timehorse mannequin added stdlib Python modules in the Lib dir labels Mar 29, 2008
    @timehorse
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    timehorse mannequin commented Apr 25, 2008

    Quick update (see thread 2636 for other updates to the Regex
    functionality): I do have a design in my mind for how to accomplish both
    Atomic Grouping and Possessive Qualifiers and it would work with either
    the existing Engine design or the new design I have been playing with.
    It's just a matter of getting around to implementing it, testing it and
    documenting it.

    I currently am having problem with Bazaar / Launchpad which are beyond
    the scope of this issue but are effecting my work. Those issues can be
    found on the Launchpad site if you look for Answers / Bugs originating
    from "timehorse".

    @timehorse
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    timehorse mannequin commented Jun 17, 2008

    I have finished work on the Atomic Grouping / Possessive Qualifiers
    support and am including a patch to achieve this; however,
    http://bugs.python.org/issue2636 should be consulted for the complete list
    of changes in the works for the Regexp engine.

    @terryjreedy
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    terryjreedy commented Aug 7, 2010

    Does the re2 work (bpo-2636) make this outdated?

    @birkenfeld
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    birkenfeld commented Aug 22, 2010

    Implemented in bpo-2636.

    @serhiy-storchaka
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    serhiy-storchaka commented Nov 11, 2014

    Some unrelated to the topic changes from the patch are committed in 30a6c74ad87f.

    @serhiy-storchaka
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    serhiy-storchaka commented Nov 11, 2014

    Reopened because definitely regex will be not adopted in 3.5.

    Here is updated to 3.5 Jeffrey's patch.

    @serhiy-storchaka
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    serhiy-storchaka commented Mar 21, 2022

    New changeset 345b390 by Serhiy Storchaka in branch 'main':
    bpo-433030: Add support of atomic grouping in regular expressions (GH-31982)
    345b390

    @ezio-melotti ezio-melotti transferred this issue from another repository Apr 9, 2022
    @hugovk
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    hugovk commented Apr 11, 2022

    Closing because GH-31982 has been merged.

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    Labels
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