[issue4199] add shorthand global and nonlocal statements
Gregory P. Smith added the comment: Closing and rejecting based on said discussion. http://mail.python.org/pipermail/python-dev/2013-June/127143.html -- nosy: +gregory.p.smith resolution: - rejected status: open - closed ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue4199 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue4199] add shorthand global and nonlocal statements
A.M. Kuchling added the comment: Bumping version to 3.4. I'll send a note to python-dev about this issue. -- versions: +Python 3.4 -Python 3.3 ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue4199 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue4199] add shorthand global and nonlocal statements
Raymond Hettinger raymond.hettin...@gmail.com added the comment: +1 on the feature as described in the PEP. -- nosy: +rhettinger ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue4199 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue4199] add shorthand global and nonlocal statements
R. David Murray rdmur...@bitdance.com added the comment: We could also just decide we don't need it :) If we do (I haven't read the PEP) does a statement with an assignment make the variable global in that scope, or does it only affect the global variable for the duration of the assignment, and otherwise the variable remains local in the scope? (I don't know which to guess, and the ambiguity is disturbing. I like the current clarity even if it is more typing.) -- nosy: +r.david.murray ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue4199 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue4199] add shorthand global and nonlocal statements
Changes by Eric Snow ericsnowcurren...@gmail.com: -- nosy: +eric.snow ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue4199 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue4199] add shorthand global and nonlocal statements
Changes by Ronald Oussoren ronaldousso...@mac.com: -- versions: +Python 3.3 -Python 3.2 ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue4199 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue4199] add shorthand global and nonlocal statements
Mark Lawrence breamore...@yahoo.co.uk added the comment: I'm not sure as to the status of this. Could it go back to (say) 3.3, is it still a candidate for 3.2(.x), or what? -- nosy: +BreamoreBoy ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue4199 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue4199] add shorthand global and nonlocal statements
Benjamin Peterson benja...@python.org added the comment: 2010/7/18 Mark Lawrence rep...@bugs.python.org: Mark Lawrence breamore...@yahoo.co.uk added the comment: I'm not sure as to the status of this. Could it go back to (say) 3.3, is it still a candidate for 3.2(.x), or what? It can't do anything until 3.3. -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue4199 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue4199] add shorthand global and nonlocal statements
Georg Brandl ge...@python.org added the comment: I do think a brief discussion after the moratorium is over would be good. -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue4199 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue4199] add shorthand global and nonlocal statements
Jeremy Hylton jer...@alum.mit.edu added the comment:
I guess there's some question about whether the syntax in the PEP was
considered carefully when it was approved. If so, I'm not sure that
we want to re-open the discussion. On the other hand, it's been a
long time since the PEP was approved and we do have a moratorium on
language changes, so it doesn't hurt to slow things down.
I'd argue that the intent of the PEP is pretty clear. You can take
any assignment statement where the LHS doesn't have subscripts, put a
nonlocal or global in front of it, and it means that all those
assignments are to global/nonlocal variables.
Jeremy
On Wed, Feb 24, 2010 at 4:20 AM, Georg Brandl rep...@bugs.python.org wrote:
Georg Brandl ge...@python.org added the comment:
I also notice that the Grammar in the PEP is more complicated:
nonlocal_stmt ::=
nonlocal identifier (, identifier)*
[= (target_list =)+ expression_list]
| nonlocal identifier augop expression_list
The Grammar in the patch is:
+global_stmt: 'global' NAME (',' NAME)* [','] ['=' testlist]
+nonlocal_stmt: 'nonlocal' NAME (',' NAME)* [','] ['=' testlist]
It appears that the PEP is trying to support:
nonlocal x = y = z = 1
nonlocal a, b = c, d = 1
It also tries to support augmented assignment; however I'm not sure what the
semantics of that should be.
Further, there is an ambiguity if too much freedom is allowed: what about
global x = 1, y
Is it declaring a global x and assigning a tuple, or declaring a global x
and a global y?
If we're going to support the PEP as written, I think we need to
modify Global() and Nonlocal() to look exactly like Assign(), but add
an extra check to verify that all of the expressions in the targets
are Name, List, or Tuple. You'd probably want to check this at the
time you are generating the AST, so that you're not stuck with some
extra state in the compiler traversal about whether you are generating
code for a Global() or an Assign().
I would not support List or Tuple as targets. Same basic problem as
above, and I don't see a use case.
I see two possibilities for the actual syntax:
1) global *either* supports multiple identifiers, *or* one identifier
and an assignment.
2) global always supports multiple identifiers, each with an optional
assignment; tuples need parentheses.
In both cases, I would keep it simple and not allow multiple targets or
augmented assignment.
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[issue4199] add shorthand global and nonlocal statements
Jeremy Hylton jer...@alum.mit.edu added the comment: Is deferred blocker a higher priority? Jeremy On Tue, Feb 23, 2010 at 4:37 PM, Georg Brandl rep...@bugs.python.org wrote: Georg Brandl ge...@python.org added the comment: High is not high enough :) -- priority: high - deferred blocker ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue4199 ___ -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue4199 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue4199] add shorthand global and nonlocal statements
Jeremy Hylton jer...@alum.mit.edu added the comment: On Sat, Dec 6, 2008 at 1:28 PM, Benjamin Peterson rep...@bugs.python.org wrote: Benjamin Peterson musiccomposit...@gmail.com added the comment: I think I may have been merging add_ast_fields when I wrote the patch. Here's a new patch that handles global x, = (5,). To do it, I added a new flag* to the Global and Nonlocal AST objects that indicates whether the value needs to be unpacked or not. You shouldn't need to do this. The unpack is implied if the number of identifiers is greater than 1. Jeremy * The flag is an int. The bool AST type was removed in py3k. Added file: http://bugs.python.org/file12254/global_nonlocal_shorthand2.patch ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue4199 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/jeremy%40alum.mit.edu -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue4199 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
Re: [issue4199] add shorthand global and nonlocal statements
I also notice that the Grammar in the PEP is more complicated:
nonlocal_stmt ::=
nonlocal identifier (, identifier)*
[= (target_list =)+ expression_list]
| nonlocal identifier augop expression_list
The Grammar in the patch is:
+global_stmt: 'global' NAME (',' NAME)* [','] ['=' testlist]
+nonlocal_stmt: 'nonlocal' NAME (',' NAME)* [','] ['=' testlist]
It appears that the PEP is trying to support:
nonlocal x = y = z = 1
nonlocal a, b = c, d = 1
If we're going to support the PEP as written, I think we need to
modify Global() and Nonlocal() to look exactly like Assign(), but add
an extra check to verify that all of the expressions in the targets
are Name, List, or Tuple. You'd probably want to check this at the
time you are generating the AST, so that you're not stuck with some
extra state in the compiler traversal about whether you are generating
code for a Global() or an Assign().
This approach makes the compiler code very simple. We use exactly the
same code for Global(), Nonlocal(), and Assign(). It does have the
downside that you need to enforce this unwritten constraint of the AST
in ast.c and in the ast module.
It also means that the AST will change in a non-backwards compatible
way. I don't see how to do that given that we're also changing the
language spec. (Do you want to include the spec change in your
patch?)
Jeremy
On Tue, Feb 23, 2010 at 6:41 PM, Jeremy Hylton jer...@alum.mit.edu wrote:
On Sat, Dec 6, 2008 at 1:28 PM, Benjamin Peterson
rep...@bugs.python.org wrote:
Benjamin Peterson musiccomposit...@gmail.com added the comment:
I think I may have been merging add_ast_fields when I wrote the patch.
Here's a new patch that handles global x, = (5,). To do it, I added a
new flag* to the Global and Nonlocal AST objects that indicates whether
the value needs to be unpacked or not.
You shouldn't need to do this. The unpack is implied if the number of
identifiers is greater than 1.
Jeremy
* The flag is an int. The bool AST type was removed in py3k.
Added file: http://bugs.python.org/file12254/global_nonlocal_shorthand2.patch
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[issue4199] add shorthand global and nonlocal statements
A.M. Kuchling li...@amk.ca added the comment: Bumping priority so this doesn't get forgotten before 3.2; it seems important because it fixes noncompliance with a PEP. -- nosy: +akuchling priority: normal - high ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue4199 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue4199] add shorthand global and nonlocal statements
Changes by Antoine Pitrou pit...@free.fr: -- priority: critical - normal ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue4199 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue4199] add shorthand global and nonlocal statements
Georg Brandl ge...@python.org added the comment: Postponed to 3.2. -- nosy: +georg.brandl versions: +Python 3.2 -Python 3.1 ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue4199 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue4199] add shorthand global and nonlocal statements
Changes by Jeremy Hylton jer...@alum.mit.edu: -- nosy: +jhylton ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue4199 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue4199] add shorthand global and nonlocal statements
Changes by Benjamin Peterson [EMAIL PROTECTED]: -- priority: high - critical ___ Python tracker [EMAIL PROTECTED] http://bugs.python.org/issue4199 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue4199] add shorthand global and nonlocal statements
Amaury Forgeot d'Arc [EMAIL PROTECTED] added the comment: - the add_ast_fields() function seems to be added by this patch, but it is already in svn. - Are 1-tuple supported? t = [1] global a, = t -- nosy: +amaury.forgeotdarc ___ Python tracker [EMAIL PROTECTED] http://bugs.python.org/issue4199 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue4199] add shorthand global and nonlocal statements
Benjamin Peterson [EMAIL PROTECTED] added the comment: I think I may have been merging add_ast_fields when I wrote the patch. Here's a new patch that handles global x, = (5,). To do it, I added a new flag* to the Global and Nonlocal AST objects that indicates whether the value needs to be unpacked or not. * The flag is an int. The bool AST type was removed in py3k. Added file: http://bugs.python.org/file12254/global_nonlocal_shorthand2.patch ___ Python tracker [EMAIL PROTECTED] http://bugs.python.org/issue4199 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue4199] add shorthand global and nonlocal statements
Benjamin Peterson [EMAIL PROTECTED] added the comment: Please review. -- keywords: +needs review stage: - patch review type: - feature request ___ Python tracker [EMAIL PROTECTED] http://bugs.python.org/issue4199 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue4199] add shorthand global and nonlocal statements
New submission from Benjamin Peterson [EMAIL PROTECTED]: PEP 3104 says that the nonlocal and global statements should allow a shorthand. (global x; x = 3 == global x = 3) This patch implements that. -- components: Interpreter Core files: global_nonlocal_short_assign.patch keywords: patch messages: 75193 nosy: benjamin.peterson priority: high severity: normal status: open title: add shorthand global and nonlocal statements versions: Python 3.1 Added file: http://bugs.python.org/file11880/global_nonlocal_short_assign.patch ___ Python tracker [EMAIL PROTECTED] http://bugs.python.org/issue4199 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue4199] add shorthand global and nonlocal statements
Changes by Benjamin Peterson [EMAIL PROTECTED]: Removed file: http://bugs.python.org/file11880/global_nonlocal_short_assign.patch ___ Python tracker [EMAIL PROTECTED] http://bugs.python.org/issue4199 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
