[Python-Dev] locals(), closures, and IronPython... (original) (raw)

Dino Viehland dinov at exchange.microsoft.com
Tue Mar 6 00:45:48 CET 2007

Thanks Guido. It might take some time (and someone may very well beat me to it if they care a lot) but I'll see if we can get the PEP started.

-----Original Message----- From: gvanrossum at gmail.com [mailto:gvanrossum at gmail.com] On Behalf Of Guido van Rossum Sent: Monday, March 05, 2007 2:14 PM To: Dino Viehland Cc: python-dev at python.org Subject: Re: [Python-Dev] locals(), closures, and IronPython...

Jeremy Hylton has been asking questions about this too at the sprint after PyCon. I'm tempted to accept that the exact behavior of locals() is implementation-defined (IOW undefined :-) as long as it includes the locals defined in the current scope; whether it also includes free variables could be debatable. I don't know too many good use cases for locals() apart from "learning about the implementation" I think this might be okay. Though a PEP might be in order to get agreement between users, developers and other implementation efforts (e.g. PyPy, Jython).

On 3/5/07, Dino Viehland <dinov at exchange.microsoft.com> wrote:

def a(): x = 4 y = 2 def b(): print y, locals() print locals() b() a() in CPython prints: {'y': 2, 'x': 4, 'b': <function b at 0x020726F0>} 2 {'y': 2} I'm wondering if it's intentional that these don't print dictionaries w/ the same contents or if it's more an accident of the implementation. In other words would it be reasonable for IronPython to promote all of the locals of a into b's dictionary when both a and b call locals? We currently match CPython's behavior here - at least in what we display although possibly not in the lifetimes of objects. We're considering an internal change which might alter the behavior here though and end up displaying all the members.

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-- --Guido van Rossum (home page: http://www.python.org/~guido/)

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