Since there is voting going on, -1 on changing the guarantees of `dict`. If 
ordering is important, OrderedDict is more explicit and more obvious to the 
over reading the code, even if the underlying implementation is identical.

Good luck teaching people about why Python went from OrderedDict to 
UnorderedDict within a version. I remember learning about this same thing in 
C++ and just thinking “wut?”. And they just added a new type and said to stop 
using the old one – not changing something that people already understand.

Better to underspecify the default dict and offer explicitly named extensions 
(DefaultDict, OrderedDict, etc.) for those who want more guarantees.

Cheers,
Steve

Top-posted from my Windows phone

From: Peter Ludemann via Python-Dev
Sent: Sunday, November 5, 2017 12:53
To: Sven R. Kunze
Cc: Python-Dev
Subject: Re: [Python-Dev] Guarantee ordered dict literals in v3.7?

Isn't ordered dict also useful for **kwargs? 

If it turns out that there's a dict implementation that's faster by not 
preserving order, collections.UnorderedDict could be added.
There could also be specialized implementations that pre-size the dict (cf: C++ 
unordered_map::reserve), etc., etc.
But these are all future things, which might not be necessary.

On 5 November 2017 at 12:44, Sven R. Kunze <srku...@mail.de> wrote:
+1 from me too.

On 04.11.2017 21:55, Jim Baker wrote:
+1, as Guido correctly recalls, this language guarantee will work well with 
Jython when we get to the point of implementing 3.7+. 

On Sat, Nov 4, 2017 at 12:35 PM, Guido van Rossum <gu...@python.org> wrote:
This sounds reasonable -- I think when we introduced this in 3.6 we were 
worried that other implementations (e.g. Jython) would have a problem with 
this, but AFAIK they've reported back that they can do this just fine. So let's 
just document this as a language guarantee.

On Sat, Nov 4, 2017 at 10:30 AM, Stefan Krah <ste...@bytereef.org> wrote:

Hello,

would it be possible to guarantee that dict literals are ordered in v3.7?


The issue is well-known and the workarounds are tedious, example:

   https://mail.python.org/pipermail/python-ideas/2015-December/037423.html


If the feature is guaranteed now, people can rely on it around v3.9.



Stefan Krah



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