hs-jq

The purpose of this project is to create a competing implementation of jq, the command-line JSON processor.

Check it out

There is currently no executable. To see the tests that pass you can:

$ git clone https://github.com/sshine/hs-jq.git
$ cd hs-jq
$ stack test

Why?

• I think jq is a really cool domain-specific language, but I'm really bad at it.

  Maybe if I write an interpreter for it, I will become better at it.

• This implementation can

  • confirm that the original jq implementation works as intended.
  • document the original jq syntax as documented in JBOL.

• Writing property-based tests in Haskell is a lot more convenient than doing so in C. This will give me an opportunity to experiment with hedgehog. For example, I might like to write a generator of JSON values where lists of objects share the same structure (reflecting JSON documents that jq is suitable to transform), and given such a JSON value, I might like to write a generator of jq expressions that validly address such a value.

• It would be really cool if you could transform Aeson Values using a quasi-quoter. This would give me a chance to explore how quasi-quoters work in Haskell.

  slugs :: Value -> Either JqError Value
  slugs = [jq| [ .exercises[] | .slug ] |]

Comparable projects

• stedolan/jq: "Command-line JSON processor"
• chrisdone/jl: "Functional sed for JSON"
• haskell-works/hw-jq: From 2017, appears very similar to this project.

Status

Parser: 143 out of 436 tests failed.

Contributing

If you like this project, or if you're looking for an opportunity to practice writing open source Haskell, feel free to open an issue or a PR, or send me an email. A good starting point could be to look through issues labelled "help wanted".