Description

brettcannon

opened on Mar 17, 2008

Issue body actions

BPO	2333
Nosy	@brettcannon, @mdickinson, @avassalotti, @ezio-melotti
Dependencies	bpo-2335: Backport set literals
Files	backport_dict_and_set_comprehension.diff patch_failure.log: Output of attempt to apply patch. set_and_dict_comprehensions.diff

^{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 2010-01-11.22:36:41.905>
created_at = <Date 2008-03-17.17:37:33.157>
labels = ['interpreter-core', 'type-bug']
title = 'Backport set and dict comprehensions'
updated_at = <Date 2012-11-14.09:00:10.725>
user = 'https://github.com/brettcannon'

bugs.python.org fields:

activity = <Date 2012-11-14.09:00:10.725>
actor = 'fossilet'
assignee = 'none'
closed = True
closed_date = <Date 2010-01-11.22:36:41.905>
closer = 'alexandre.vassalotti'
components = ['Interpreter Core']
creation = <Date 2008-03-17.17:37:33.157>
creator = 'brett.cannon'
dependencies = ['2335']
files = ['14661', '14670', '27981']
hgrepos = []
issue_num = 2333
keywords = ['patch', '26backport']
message_count = 11.0
messages = ['63690', '91338', '91367', '91368', '91369', '96257', '97611', '112812', '175539', '175541', '175554']
nosy_count = 6.0
nosy_names = ['brett.cannon', 'mark.dickinson', 'fossilet', 'alexandre.vassalotti', 'ezio.melotti', 'metal']
pr_nums = []
priority = 'critical'
resolution = 'accepted'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue2333'
versions = ['Python 2.7']

Activity

1. brettcannon commented on Mar 17, 2008

   

   brettcannon

   on Mar 17, 2008

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   Dict comprehensions need to be backported.
2. brettcannon

   added

   release-blocker

   interpreter-core(Objects, Python, Grammar, and Parser dirs)(Objects, Python, Grammar, and Parser dirs)

   type-bugAn unexpected behavior, bug, or errorAn unexpected behavior, bug, or error

   and removed

   release-blocker

   on Mar 17, 2008
3. avassalotti commented on Aug 5, 2009

   

   avassalotti

   on Aug 5, 2009

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   Here is a patch to backport dict and set comprehensions to the trunk.

   The patch preserves the Python 3.x's syntax and semantics of the
   feature. Although this makes dict and set comprehensions is inconsistent
   with list comprehension, I believe this is reasonable since the backport
   aimed to improve the compatibility of Python 2.x with Python 3.x.

   The patch also adds support for dict and set comprehensions to the
   'compiler' package. However, the support is quirky and use the list
   comprehension semantics of Python 2.x. This allowed me to keep the patch
   simple and to keep myself sane ;-).

   Finally, the patch changes the name of the following syntax nodes:
   'gen_expr', 'gen_iter', 'gen_if', and 'testlist_gexp'. I don't know if
   we have compatibility requirements for this; so I don't know if this is
   an issue.
4. avassalotti

   changed the title [-]Backport dict comprehensions[/-] [+]Backport set and dict comprehensions[/+] on Aug 5, 2009
5. mdickinson commented on Aug 6, 2009

   

   mdickinson

   on Aug 6, 2009

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   Alexandre, I can't get this to apply cleanly to my svn trunk checkout
   (r74328) (see attached log). Am I doing something stupid?
6. avassalotti commented on Aug 6, 2009

   

   avassalotti

   on Aug 6, 2009

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   You need to apply the set literal patch I posted in bpo-2335 first.
7. mdickinson commented on Aug 6, 2009

   

   mdickinson

   on Aug 6, 2009

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   Ah, that works. Thanks! (I'll pay more attention to the tracker
   Dependencies field in future.)
8. avassalotti commented on Dec 11, 2009

   

   avassalotti

   on Dec 11, 2009

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   If there are no objections, I will commit this patch later this week
   after issue bpo-2335.
9. avassalotti commented on Jan 11, 2010

   

   avassalotti

   on Jan 11, 2010

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   Committed in r77422.
10. avassalotti

    closed this as completedon Jan 11, 2010
11. metal commented on Aug 4, 2010

    

    metalmannequin

    on Aug 4, 2010

    Mannequin

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    How about fixing set.__repr__ ?
12. fossilet commented on Nov 14, 2012

    

    fossiletmannequin

    on Nov 14, 2012

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    Great they are backported to 2.7. Dictionary and set comprehensions are not documented in the tutorial of 2.7, though they are in the language reference. Is it OK to add these to the tutorial? I've uploaded a patch.
13. ezio-melotti commented on Nov 14, 2012

    

    ezio-melotti

    on Nov 14, 2012

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    Is it OK to add these to the tutorial? I've uploaded a patch.

    Yes, but please create a new issue.

    How about fixing set.__repr__ ?

    Is it broken?
14. fossilet commented on Nov 14, 2012

    

    fossiletmannequin

    on Nov 14, 2012

    Mannequin

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    I think metal means that the different ways set is repr'd in 2.7 and 3.

    In 2.7:

    In [9]: a = {x for x in 'abracadabra' if x not in 'abc'}

    In [10]: repr(a)
    Out[10]: "set(['r', 'd'])"

    In 3.2：
    In [6]: a = {x for x in 'abracadabra' if x not in 'abc'}

    In [7]: repr(a)
    Out[7]: "{'r', 'd'}"

    We were saying not changing __repr__ in bpo-2335.
15. ezio-melotti

    transferred this issue fromon Apr 10, 2022

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