Hi, Yes, object properties in JSON are not ordered, by definition. But for humans it can make sense. Converting your domain objects to OrderedDictionaries or overwriting #neoJSONOn: are valid ways to control NeoJSON. However, I also think that it might be possible to solve the ordering requirement with a regular mapping, provided I make a little internal change - I will investigate that and report back. Sven
On 30 Jun 2016, at 17:29, PBKResearch <peter@pbkresearch.co.uk> wrote:
Bernardo
Thanks for this. After sending my previous mail, I did what I should have done first and looked at list of collection objects in the system browser. So I discovered OrderedDictionary for the first time. I am pleased to see that this is the key to the solution.
Peter
From: Pharo-users [mailto:pharo-users-bounces@lists.pharo.org] On Behalf Of Bernardo Ezequiel Contreras Sent: 30 June 2016 16:17 To: Any question about pharo is welcome <pharo-users@lists.pharo.org> Subject: Re: [Pharo-users] Provide a mapping for a collection of <Association>s in NeoJSON
Peter, i had the same issue, i couldn't find the way to do it, but i hack my own writing like this
NDBFood>>neoJsonOn: neoJSONWriter "custom writing"
neoJSONWriter writeMap: (OrderedDictionary new add: 'ndb_no' -> ndbno; add: 'full_name' -> name; add: 'food_group' -> fg; add: 'factors' -> self factors; add: 'nutrients' -> self nutrients; yourself)
i just implement my own writing for my objects.
HTH
On Thu, Jun 30, 2016 at 12:06 PM, PBKResearch <peter@pbkresearch.co.uk> wrote:
Hello
I have recently used NeoJSON for the first time. All went pretty well, but I would like to make a small tweak to the output, which probably involves defining a mapping. I have read through the information in the NeoJSON pdf, and also looked at the class comments, but I am a bit lost. Could Sven or anyone please give me a hint?
What I want is to construct a JSON object as a Pharo dictionary, but then control the order in which the fields are output to the JSON file. Clearly the order is irrelevant for a computer, but it could be helpful to a human reader to put them in an order which reflects the way humans think about the objects. The keys of a dictionary are of course unordered, so this is not possible, but if we step back a bit we see that a dictionary is often constructed from a collection of associations; if we could stop at this stage, and have a mapping which outputs the associations in the order in which they appear in the collection, this would give the control I am looking for.
Am I talking nonsense, or is there any way of implementing this using NeoJSON mappings?
Best wishes
Peter Kenny
-- Bernardo E.C.
Sent from a cheap desktop computer in South America.