json-edit.hs

#!/usr/bin/env stack
-- stack --resolver lts-13.15 script
{-# LANGUAGE OverloadedStrings, NoImplicitPrelude #-}

import Language.Haskell.Interpreter
import Options.Applicative.Simple
import Protolude hiding (to)
import Prelude (String)
import Control.Lens hiding (set)
import Data.Aeson
import Data.Aeson.Lens

main = do
  ((file, lensArg, edit), ()) <-
    simpleOptions
      "json-edit"
      "Edit a json file based on lenses"
      ""
      ((,,) <$> strOption (short 'f' <> metavar "FILE") <*> strArgument (metavar "LENS") <*> switch (short 'e' <> long "--edit"))
      empty

  fileContent <- readFile file
  if edit
    then return ()
    else do
    lens <- fmap runTraversal (interpretLens lensArg)
    liftIO . print $ (fileContent ^.. lens)


interpretLens :: String -> IO (ReifiedTraversal' Text Text)
interpretLens s = do
  result <- runInterpreter $ do
    setImports ["Data.Aeson", "Data.Aeson.Lens", "Control.Lens", "Control.Lens.Internal.Prism", "Data.Text", "Prelude"]
    interpret ("Traversal "<> (parens s)) infer
  case result of
    Right prism -> return prism
    Left e@(WontCompile errors) -> traverse_ (putStrLn . errMsg) errors >> exitFailure
    Left e -> print e >> exitFailure

This is a (failed) attempt at making a tool that allows you to zoom into part of a json file (or any lens for that matter) with your editor.