Output with consistent key ordering

[zostay]

Every time you call .to-json, this class outputs the keys in a different order. It would be very helpful if .to-json always output the keys in a fixed order, especially for keeping git patches more helpfully concise.

In an ideal world, we could all agree on what that order was and it probably wouldn't alphabetical because the most important information is problem name, version, authors, license, source, with depends, resources, and other bits toward the bottom, but even alphabetical order would be better than order by random.

It should be possible to make it alphabetical by passing the :sorted-keys option to JSON::Fast, which ultimate performs the serialization. However, that has to go through JSON::Class and JSON::Marshal somehow.

[jonathanstowe]

Passing :sorted-keys from JSON::Class -> JSON::Marshal -> JSON::Fast is eminently doable, however short of making a new to-json for JSON::Marshall (which I'm not inclined to do,) having the keys in a user specified order would need to be supported in ```JSON::Fast````

[jaguart]

• Shame we can't pass in a comparison-sub where $a and $b have been set to the keys (nested / delimited)
• For me, I want my META6.json organised where required keys come before the optional and at the end, the rarely-used-by-me :)
• P.S. I realise this is really a JSON::Fast request

[jonathanstowe]

Oh I totally agree, if I was editing the META6 by hand I'd put the name, description , version etc at the top and it's a pain that this gets undone.

However I really can't see a way of making this happening without the support of the thing that actually produces the JSON string.

[jaguart]

See https://gist.github.com/jaguart/bd64157bcfa8271ad5bed69a286e0613 - I'm thinking you could override the .sort method on the hash to get JSON::Fast to produce consistent ordering. Apologies for newbie code - but the concept seems to work...

[lizmat]

FYI: timo/json_fast#83

[jonathanstowe]

Obviously the majority of the changes would need to be in https://github.com/jonathanstowe/JSON-Class and https://github.com/jonathanstowe/JSON-Marshal and the basic requirement, as I see it, is that a class passed to the marshal of JSON::Marshal can define itself which order the keys are output or the order of the keys can be specified there as an argument, once all that is in place it's basically implement the default order for META6 (because the to-json is that of JSON::Class, any arbitrary ordering specified by the user comes for free.) I actually have a slightly different plan but it's waiting on a PR on another module at the moment.