Documentation

A quasiquoter, which generates record expressions and types, depending on the context it's used in.

Here is how you can use it to declare types:

type Person = 
  [record| {name :: String, birthday :: {year :: Int, month :: Int, day :: Int}} |]

To declare functions:

getAge :: [record| {name :: String, age :: Int} |] -> Int

To declare values:

person :: Person
person =
  [record| {name = "Grigori Yakovlevich Perelman", 
            birthday = {year = 1966, month = 6, day = 13}} |]

A quasiquoter, which generates a Lens. Lens is your interface to accessing and modifying the fields of a record.

Here is how you can use it:

getPersonBirthdayYear :: Person -> Int
getPersonBirthdayYear =
  Record.Lens.view ([lens|birthday|] . [lens|year|])

For your convenience you can compose lenses from inside of the quotation:

setPersonBirthdayYear :: Int -> Person -> Person
setPersonBirthdayYear =
  Record.Lens.set [lens|birthday.year|]

You can also use this function to manipulate tuples of arity up to 24:

mapThirdElement :: (Char -> Char) -> (Int, String, Char) -> (Int, String, Char)
mapThirdElement =
  Record.Lens.over [lens|3|]

A shorthand alias to record.

A shorthand alias to lens.