Re: [Python-Dev] PEP: Ordered Class Definition Namespace

On 06/07/2016 11:13 AM, Eric Snow wrote: On Tue, Jun 7, 2016 at 11:01 AM, Ethan Furman wrote: On 06/07/2016 10:51 AM, Eric Snow wrote: Specification = * types for which `__prepare__()`` returned something other than ``OrderedDict`` (or a subclass)

Re: [Python-Dev] PEP: Ordered Class Definition Namespace

On 07.06.16 20:51, Eric Snow wrote: Hi all, Following discussion a few years back (and rough approval from Guido [1]), I started work on using OrderedDict for the class definition namespace by default. The bulk of the effort lay in implementing OrderedDict in C, which I got landed just in time

Re: [Python-Dev] PEP: Ordered Class Definition Namespace

> On Jun 7, 2016, at 4:12 PM, Nick Coghlan wrote: > > By the time decorators run, the original execution namespace is no > longer available - the contents have been copied into the class dict, > which will still be a plain dict (and there's a lot of code that calls >

Re: [Python-Dev] PEP: Ordered Class Definition Namespace

On Tue, Jun 07, 2016 at 11:39:06AM -0700, Eric Snow wrote: > On Tue, Jun 7, 2016 at 11:32 AM, Terry Reedy wrote: > > On 6/7/2016 1:51 PM, Eric Snow wrote: > > > >> Note: just to be clear, this PEP is *not* about changing > > > >> ``type.__dict__`` to ``OrderedDict``. > > > > By

Re: [Python-Dev] PEP: Ordered Class Definition Namespace

On 7 June 2016 at 16:03, Raymond Hettinger wrote: > >> On Jun 7, 2016, at 10:51 AM, Eric Snow wrote: >> >> This PEP changes the default class definition namespace to ``OrderedDict``. > > I think this would be a nice improvement. > >>

Re: [Python-Dev] PEP: Ordered Class Definition Namespace

> On Jun 7, 2016, at 10:51 AM, Eric Snow wrote: > > This PEP changes the default class definition namespace to ``OrderedDict``. I think this would be a nice improvement. > Furthermore, the order in which the attributes are defined in each class > body will now be

Re: [Python-Dev] PEP: Ordered Class Definition Namespace

On 06/07/2016 03:27 PM, Eric Snow wrote: Not all attrs are writable and it's a case-by-case situation: some of the ones that are writable started out read-only and changed once there was a valid reason. If anything, it's arguably safer in general to take an immutable-by-default approach. I'm

Re: [Python-Dev] PEP: Ordered Class Definition Namespace

On Tue, Jun 7, 2016 at 2:34 PM, Ethan Furman wrote: > On 06/07/2016 02:20 PM, Eric Snow wrote: >> I think both of those make __definition_order__ more complicated and >> less useful. As the PEP stands, folks can be confident in what >> __definition_order__ represents. What

Re: [Python-Dev] PEP: Ordered Class Definition Namespace

On Tue, Jun 7, 2016 at 2:34 PM, Nick Coghlan wrote: > On 7 June 2016 at 14:20, Eric Snow wrote: >> What would you consider to be the >> benefit of a mutable (or replaceable) __definition_order__ that >> outweighs the benefit of a simpler

Re: [Python-Dev] PEP: Ordered Class Definition Namespace

On 7 June 2016 at 14:20, Eric Snow wrote: > On Tue, Jun 7, 2016 at 12:30 PM, Nick Coghlan wrote: >> The main alternative would be to make __definition_order__ writable, >> so the default behaviour would be for it to reflect the original class >>

Re: [Python-Dev] PEP: Ordered Class Definition Namespace

On 06/07/2016 02:20 PM, Eric Snow wrote: On Tue, Jun 7, 2016 at 12:30 PM, Nick Coghlan wrote: On 7 June 2016 at 10:51, Eric Snow wrote: * ``__definition_order__`` is a tuple * ``__definition_order__`` is a read-only attribute Thinking about the class decorator use case, I think this may

Re: [Python-Dev] PEP: Ordered Class Definition Namespace

On Tue, Jun 7, 2016 at 12:30 PM, Nick Coghlan wrote: > On 7 June 2016 at 10:51, Eric Snow wrote: >> * ``__definition_order__`` is a tuple >> * ``__definition_order__`` is a read-only attribute > > Thinking about the class decorator use case, I

Re: [Python-Dev] PEP: Ordered Class Definition Namespace

On 7 June 2016 at 10:51, Eric Snow wrote: > Specification > = > > * the default class *definition* namespace is now ``OrderdDict`` > * the order in which class attributes are defined is preserved in the > new ``__definition_order__`` attribute on each

Re: [Python-Dev] PEP: Ordered Class Definition Namespace

> From: Eric Snow > Sent: Tuesday, June 07, 2016 2:52 PM > To: Émanuel Barry > Cc: Python-Dev > Subject: Re: [Python-Dev] PEP: Ordered Class Definition Namespace > > "dunder" names (not just methods) will not be present in > __definition_order__. I'll add an

Re: [Python-Dev] PEP: Ordered Class Definition Namespace

On Tue, Jun 7, 2016 at 11:45 AM, Ethan Furman wrote: > On 06/07/2016 11:13 AM, Eric Snow wrote: >> A __definition_order__ in the class body always takes precedence. So >> a supplied value will be honored (and not replaced with None). > > Will the supplied __definition_order__

Re: [Python-Dev] PEP: Ordered Class Definition Namespace

On Tue, Jun 7, 2016 at 11:36 AM, Émanuel Barry wrote: >> From: Eric Snow >> * "dunder" attributes (e.g. ``__init__``, ``__module__``) are ignored > > What does this imply? If I define some __dunder__ methods, will they simply > not be present in __definition_order__? What if I

Re: [Python-Dev] PEP: Ordered Class Definition Namespace

On 06/07/2016 11:13 AM, Eric Snow wrote: On Tue, Jun 7, 2016 at 11:01 AM, Ethan Furman wrote: On 06/07/2016 10:51 AM, Eric Snow wrote: Specification = * types for which `__prepare__()`` returned something other than ``OrderedDict`` (or a subclass)

Re: [Python-Dev] PEP: Ordered Class Definition Namespace

On Tue, Jun 7, 2016 at 11:32 AM, Terry Reedy wrote: > On 6/7/2016 1:51 PM, Eric Snow wrote: > >> Note: just to be clear, this PEP is *not* about changing > >> ``type.__dict__`` to ``OrderedDict``. > > By 'type', do you mean the one and one objected named 'type or the class >

Re: [Python-Dev] PEP: Ordered Class Definition Namespace

> From: Eric Snow > Sent: Tuesday, June 07, 2016 1:52 PM > To: Python-Dev > Subject: [Python-Dev] PEP: Ordered Class Definition Namespace > > > Currently the namespace used during execution of a class body defaults > to dict. If the metaclass defines ``__prepa

Re: [Python-Dev] PEP: Ordered Class Definition Namespace

On 6/7/2016 1:51 PM, Eric Snow wrote: Note: just to be clear, this PEP is *not* about changing > ``type.__dict__`` to ``OrderedDict``. By 'type', do you mean the one and one objected named 'type or the class being defined? To be really clear, will the following change? >>> class C: pass

Re: [Python-Dev] PEP: Ordered Class Definition Namespace

On Tue, Jun 7, 2016 at 11:01 AM, Ethan Furman wrote: > On 06/07/2016 10:51 AM, Eric Snow wrote: >> Specification >> = > > >>* types for which `__prepare__()`` returned something other than >> ``OrderedDict`` (or a subclass) have their

Re: [Python-Dev] PEP: Ordered Class Definition Namespace

On 06/07/2016 10:51 AM, Eric Snow wrote: My intention was to land the patch soon, having gone through code review during PyCon. However, Nick pointed out to me the benefit of having a concrete point of reference for the change, as well as making sure it isn't a problem for other

[Python-Dev] PEP: Ordered Class Definition Namespace

Hi all, Following discussion a few years back (and rough approval from Guido [1]), I started work on using OrderedDict for the class definition namespace by default. The bulk of the effort lay in implementing OrderedDict in C, which I got landed just in time for 3.5. The remaining work was