tyingtheknot.hs

{-# LANGUAGE
    TypeOperators
  , TemplateHaskell
  #-}
module Tie where

import Prelude hiding ((.), id)
import Control.Category
import Data.Record.Label

-- Simple test.

data Person = Person
  { _name :: String
  , _job  :: Job
  }

data Job = Job
  { _title :: String
  , _who   :: Person
  }

$(mkLabels [''Person])
$(mkLabels [''Job])

me    :: Person
me    = setL job myJob (Person "Tom" myJob)

myJob :: Job
myJob = setL who me (Job "Software Engineer" me)

test :: String
test = getL (title . job . who . job . who . job . who . job) me