Preserve fields order in dhall-to-json

[countoren]

It could be helpful to have dhall-to-json to maintain the field order of a Json object in dhall record sets(or some other alternative type) instead of having it order alphabetically.

some application might be effected by the fields order of a Json for example. Or some user will order the field in a specific way in order for them to have the Json more readable (sub objects fields usually are pushed to the end).

this ticket is base on this topic in dhall discourse

[Gabriella439]

It appears that this is a limitation of using the aeson package for decoding JSON, at least for decoding arbitrary JSON Values. The reason why is that the Value type used to represent schema-free JSON uses a HashMap to represent JSON objects and that representation does not preserve the key order.

So it looks like this might not be fixable without switching to another underlying package for working with JSON values.

[Gabriella439]

Oh, also, here is the relevant aeson issue discussing this limitation: https://github.com/haskell/aeson/issues/368

[sjakobi]

https://github.com/dhall-lang/dhall-haskell/issues/1813 is related.