[Python-ideas] Python Object Notation (PyON)

[Josiah Carlson]

Has anyone in this discussion used either Yaml or Json?  I've used
both.  And I much prefer Json.  The libraries to encode and decode in
most languages worth mentioning are *very* fast (comparable to
cPickle).  Yaml...not so much.  Never mind that Yaml has some ugly
bits that make it's use as a configuration language (which isn't
uncommon) have some very unpleasant gotchas.

Adding *yet another* Python-centric serialization language seems more
than a little silly to me; it seems like a waste of time.  Of course
you are free to develop this method as you see fit, but don't be
surprised if you bring it to python-dev and they say, "no."

 - Josiah

On Wed, Nov 5, 2008 at 6:25 AM, Bruce Leban <bruce at leapyear.org> wrote:
> I've been following this discussion and it seems like implementation is way
> ahead of design. I'm looking at the syntax below and seeing it has no
> advantage over text pickle format to me. Sure it's a bit more readable,
> but as it stands, this is really only going to be useful for python-python operations and the existing pickle formats do that fine.
> Why would we need another one-off markup language?
> All that you've said so far about Yaml was "I didn't yet made comparison with yaml. I should do that too. Now I can only say that yaml is much complicated notation (IMHO)."
> In fact, I think a subset of Yaml is all that is necessary for this, just as
> Json is (now) a subset of Yaml. My suggestion is that Json < Pyon < Yaml is
> a good goal.
> I agree Yaml is complicated and the docs don't help as much as they could
> with too much emphasis on syntax and not enough on semantics. However, Yaml
> has already addressed issues like typing and defining objects to be reused.
> I'm not a Yaml expert so I may have gotten some of the following wrong, but
> it should be enough to give a general idea:
>
> [int, float, str]
> ==
> [!type int, !type float, !type str]
> or maybe
>  [!py!type int, !py!type float, !py!type str]
>
> and
>
> _p__0=(1,2)
> _p__1=[1,2]
> [_p__0,_p__1,_p__0,_p__1]
>
> ==
>
> [&_p__0 !tuple [1,2],  &_p__1 [1,2], *_p__0, *_p__1]
>
> or
>
> - &_p__0 (1,2)
> - &_p__1 [1,2]
> - *_p__0
> - *_p__1
>
>
> and
>
> lst=['foo',lst]
> _p__1=C(lst=lst,d=d,parent=_p__1)
> d={'a':'bar','c':d,'b':lst,'d':_p__1}
> [lst,d,_p__1]
>
> ==?
>
> [&lst ['foo', *lst]], &d{'a','bar','c':*d,'b':*lst,'d':&_p__1 !!C {lst:
> *lst, d: *d, parent: *_p__1}}]
>
> or in a multi-line format:
>
> - &lst ['foo, *lst]
> - &d
>     'a': 'bar'
>     'c': *d
>     'b': *lst
>     'd': &_p__1 !!C
>         lst: *lst
>         d: *d
>         parent: *_p__1
>
> The only thing I see missing from Yaml is forward references which might be
> nice for producing more readable output in some cases but I don't think is
> technically necessary.
>
> --- Bruce
>
>
> On Wed, Nov 5, 2008 at 2:57 AM, Arnaud Delobelle <arnodel at googlemail.com>
> wrote:
>>
>> On 05/11/2008, Zaur Shibzoukhov <szport at gmail.com> wrote:
>> > I have added support for naming objects in dumps,  cross-references
>> > and declarative support in dumps/loads too.
>>
>> This is great stuff!
>>
>> > I can't now commit changes. This night I will commit changes to
>> > sources and update project pages.
>> >
>> > Here are examples of how it works now:
>> [...]
>> > >>> pyon.dumps([lst,d,c], fast = False, lst=lst, d=d)
>>
>> How about changing the syntax slightly so that the given names are all
>> in a dictionary:
>>
>> >>> pyon.dumps([lst, d, c], fast=False, given={'lst':lst, 'd':d})
>> (or one could use given=dict(lst=lst, d=d))
>>
>> This would have two advantages:
>>
>> * eliminate the rist of keyword argument name collision
>> * one could put all the 'given' objects in a dictionary and then
>> 'pickle' expressions as needed using this method.  Later pyon.loads
>> could be passed this dictionary so that the objects can be unpickled
>> correctly.
>>
>> I think this idea is good as it would make it possible to pickle some
>> objects that contain unpicklable objects just by declaring them as
>> 'given'.
>
> <snip>
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