bjornkihlberg/PureScript-Tutorials

Tutorials on using PureScript

PureScript-Tutorials

Tutorials on using PureScript

Cheat sheet

Initialize new project

pulp --psc-package init

Show instance

newtype Box a = Box a

instance showBox :: (Show a) => Show (Box a) where
    show (Box x) = "Box " <> (show x)

Records

Structural record type

type MyRecord = { a :: Int, b :: Number, c :: String }

Nominal record type

newtype MyRecord = MyRecord { a :: Int, b :: Number, c :: String }

Record patterns

f :: forall a. { i :: Int | a } -> { i :: Int }
f { i } = { i: i + 1 }

f :: forall a. { i :: Int | a } -> { i :: Int | a }
f x = x { i = x.i + 1 }

f :: forall a b. a -> b -> { x :: a, y :: b, z :: String }
f = { x: _, y: _, z: "Hello" }

f :: forall a b c. { x :: a | c } -> b -> { x :: b | c }
f = _ { x = _ }

f :: forall a b. { x :: a | b } -> a
f = _.x