Hledger: Feature req: Add json as output format

[varac]

The --output-format option accepts txt and csv so far. For better parsing of the output, json would be awesome !

[jeevcat]

Currently I use the hledger-api for json-formatted data, which is fantastic but is limited to only a few commands. I would also appreciate a feature like this.

[simonmichael]

Both would be good to improve, patches welcome!

[simonmichael]

Copied from #1069:

We have ToJSON instances in hledger-web/Hledger/Web/JSON.hs, which perhaps should move into hledger-lib; then it shouldn't be too hard to add this, handling any tricky cases like mutual references as hledger-web does. See also hledger-web/Hledger/Web/Handler/MiscR.hs.

[entropitor]

There seems to be an experimental json output but it's not actually outputting JSON but some sort of DSL, is this something that broke or was it never implemented?

[simonmichael]

@entropitor could you show a repro of what you're talking about ?

https://hledger.org/hledger-web.html#json-api was updated yesterday, describing the JSON served by hledger-web. If someone wants to add this output format to some hledger commands, starting with print, that would be great.

[entropitor]

When I have the following test.ledger file

2020/05/23 * My favorite resto
  expenses:food                       € 26.8
  assets:cash                         € -26.8

And run:

hledger -f test.ledger bal -O json

I get:

Array [Array [Array [String "assets:cash",String "assets:cash",Number 0.0,Array [Object (fromList [("aprice",Null),("acommodity",String "\8364"),("aquantity",Object (fromList [("floatingPoint",Number -26.8),("decimalPlaces",Number 10.0),("decimalMantissa",Number -2.68e11)])),("aismultiplier",Bool False),("astyle",Object (fromList [("ascommodityside",String "L"),("asdigitgroups",Null),("ascommodityspaced",Bool True),("asprecision",Number 1.0),("asdecimalpoint",String ".")]))])]],Array [String "expenses:food",String "expenses:food",Number 0.0,Array [Object (fromList [("aprice",Null),("acommodity",String "\8364"),("aquantity",Object (fromList [("floatingPoint",Number 26.8),("decimalPlaces",Number 10.0),("decimalMantissa",Number 2.68e11)])),("aismultiplier",Bool False),("astyle",Object (fromList [("ascommodityside",String "L"),("asdigitgroups",Null),("ascommodityspaced",Bool True),("asprecision",Number 1.0),("asdecimalpoint",String ".")]))])]]],Array [Object (fromList [("aprice",Null),("acommodity",String "\8364"),("aquantity",Object (fromList [("floatingPoint",Number 0.0),("decimalPlaces",Number 10.0),("decimalMantissa",Number 0.0)])),("aismultiplier",Bool False),("astyle",Object (fromList [("ascommodityside",String "L"),("asdigitgroups",Null),("ascommodityspaced",Bool True),("asprecision",Number 1.0),("asdecimalpoint",String ".")]))])]]

[simonmichael]

I see what you mean! Thanks for the bug report.

[simonmichael]

To clarify status: I had forgotten JSON output was implemented for several commands in the last release, https://hledger.org/release-notes.html#hledger-1-17. But as reported above, it was broken, showing haskell Read output instead of JSON.

Also: command help should be updated to list JSON as a supported output format where appropriate.

[simonmichael]

This is fixed in master, and will be in the june release.