[Pharo-users] Is it bad to have an order NeoJsonObject?

Sven Van Caekenberghe sven at stfx.eu
Thu Jun 7 02:46:44 EDT 2018



> On 7 Jun 2018, at 08:16, Norbert Hartl <norbert at hartl.name> wrote:
> 
> 
> 
>> Am 07.06.2018 um 07:29 schrieb Sven Van Caekenberghe <sven at stfx.eu>:
>> 
>> Tim,
>> 
>>> On 7 Jun 2018, at 01:37, Tim Mackinnon <tim at testit.works> wrote:
>>> 
>>> Hi - I’ve hit some Json where the outputted values (they are field names) are written out in a specific order - and the author hasn’t chosen to use an array to represent those fields in a specific order.
>>> 
>>> { ‘field1’ : { ….}, ‘field2’: { … } }
>>> 
>>> I think this is technically incorrect and should be:
>>> 
>>> { [ {‘field1’ : { ….}, ‘field2’: { … } ]}
>>> 
>>> Anyway - given what I’ve got, would it be a terrible idea to create my own version NeoJsonObject and just make it a subclass of OrderedDictionary?
>>> 
>>> I can’t see any issues - but then I might be kidding myself…
>>> 
>>> Tim
>> 
>> Yea, I think you could try making a NeoJSONOrderedObject as a subclass of OrderedDictionary, modelled after NeoJSONObject. Just remember it is implemented using DNU, which will surprise you at one point.
>> 
> Wouldn‘t be setting #mapClass: on the reader to OrderedDictionary not enough? Dictionary is the default anyway.
> 
> Norbert

Yes, of course, Norbert, it keeps the order:

(NeoJSONReader on: '{"BB":1,"CC":2,"AA":3}' readStream) mapClass: OrderedDictionary; next.

  => an OrderedDictionary('BB'->1 'CC'->2 'AA'->3)

NeoJSONWriter toString: (OrderedDictionary new at: #BB put: 1; at: #CC put: 2; at: #AA put: 3; yourself). 

  => '{""BB"":1,""CC"":2,""AA"":3}'

It is not functionally 100% the same as a hypothetical NeoJSONOrderedObject, but might do.

Sven


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