module Node

import Prelude

pfunc fs : JSObject := `require('fs')`
pfunc getArgs : List String := `arrayToList(String, process.argv.slice(1))`
pfunc readFile uses (fs MkIORes Left Right) : (fn : String) -> IO (Either String String) := `(fn) => (w) => {
  let result
  try {
    let content = fs.readFileSync(fn, 'utf8')
    result = Right(undefined, undefined, content)
  } catch (e) {
    let err = ""+e
    result = Left(undefined, undefined, e)
  }
  return MkIORes(undefined, result, w)
}`

-- I wonder if I should automatically `uses` the constructors in the types
pfunc writeFile uses (fs MkIORes MkUnit) : String → String → IO (Either String Unit) := `(fn, content) => (w) => {
  let result
  try {
    fs.writeFileSync(fn, content, 'utf8')
    result = Right(undefined, undefined, MkUnit)
  } catch (e) {
      let err = ""+e
      result = Left(undefined, undefined, e)
  }
  return MkIORes(undefined, result, w)
}`

-- maybe System.exit or something, like the original putStrLn msg >> exitFailure
pfunc exitFailure : ∀ a. String → a := `(_, msg) => { throw new Error(msg) }`