WAJsonCanvas

> I migrated to Seaside 3.1, and I had a mix of NeoJSON and old style
> #jsonOn: implementations.
>
> By fixing the old style #jsonOn: to work with a WAJsonCanvas, I found
> I don't have a way to create an array definition specifying each
> element.
>
> It is, the implementation delegates the rendering to the Collection
> class, but I can't control it to do it manually:
>
>
> However, I implemented an #element: selector in WAJsonCanvas as follows:
> WAJsonCanvas>>#element: aValueObject
>  ^ (self brush: (WAJsonElementBrush new)) with: aValueObject
>
> And then I could do:
>
> WAJsonCanvas builder render: [ :json |
>  json array: [
>     WADocument  allSubclasses do:[:each |
>        json element: [
>           json object: [ json key: 'name' value: each name ]
>        ]
>     ]
>   ]
> ]
>
> which generates the following output:
> [{"name": "WAXmlDocument"}, {"name": "WAJsonDocument"}, {"name":
> "WAHtmlDocument"}, {"name": "WAUnescapedDocument"}, {"name":
> "WAPrettyPrintedDocument"}]
>
> Without using the #element: brush all the elements aren't comma
> separated. Maybe there is another way of doing it, delegating it to
> the array brush.
>
> Is this okay? Can this be added to Seaside-JSON-Core?
>
> Regards,
>
> Esteban A. Maringolo
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> Hi Esteban,
>
> I don't think you need the extra #element method.
> How about the following:
>
>         WAJsonCanvas builder render: [ :json |
>                 json array: [
>                         WADocument  allSubclasses do:[:each |
>                                 json value: [  json object: [ json key: 'name' value: each name ] ]]]
>
> this produces:
>
>         '[{"name": "WAXmlDocument"}, {"name": "WAJsonDocument"}, {"name": "WAHtmlDocument"}, {"name": "WAUnescapedDocument"}, {"name": "WAPrettyPrintedDocument"}]'
>
> But this example makes me think... I would actually want to write it as follows:
>
>         WAJsonCanvas builder render: [ :json |
>                 json array: [
>                         WADocument  allSubclasses do:[:each |
>                                 json object: [ json key: 'name' value: each name ]]]]
>
> i.e. without the #value: message. I would expect the canvas to put a comma in between different objects. An 'object' is actually a 'value' in the json syntax.
> It might make sense.

> Hi Esteban,
>
>> But even when it's not a common use case scenario, you could have a
>> mixed objects array.
>>
>> Something like: ['string', 3.14, {key: 'value', foo: 'baz'}, [...], false]
>>
>> In that case it wouldn't be just "extending" the WAJsonObjectBrush
>> openTag, but it should be something at other level, that let you
>> manage the elements any way you want. Hence the #element: method.
>
> I believe this is exactly the way #value: works.
> Is there a reason why the following does work for you in such a case?
>
> WAJsonCanvas builder render: [ :json |
>         json value:  (Array with: 'string' with: 3.14 with: (Dictionary new at: 'key' put: 'value';yourself))
>         ]
>
> The way I understand how the canvas is designed is that #value still supports the 'old-style' conversion of Smalltalk object to json, and that #object:, #array, etc. allow to build json directly without the intermediate stop of building arrays and dictionaries. But I must admit I have not played with the JSON Canvas in 3.1 yet.

>
> On 22 Feb 2014, at 22:54, Philippe Marschall <[hidden email]> wrote:
>
>> That's a pretty simple fix
>>
>> WAJsonObjectBrush >> #openBrush
>>    canvas writeIfNotFirst: ', '.
>>    self document openObject
>>
>> seems to do the trick. I'm a bit reluctant to commit because I'm not
>> sure if it will break anything. Tests are green though.
>
> Though it is an interface change, perhaps it's the best thing to change it now (for 3.1.1) before too many people have migrated to Seaside 3.1 ?