gistfile1.txt

# Sum types with type parameters
data Maybe T =
  | Some T
  | None

data Pet =
  | Dog
  | Cat
  | Hamster

# Product types with named fields
data Person =
  .name String
  .age  Int
  .pet Maybe Pet

const bob = Person
  .name "Bob"
  .age 42
  .pet Some Hamster

# Currying by default, equivalent to |name| |age| ...
const make_person = |name, age| Person
  .name name
  .age age
  .pet None

# HM type inference, inferred as Int -> Int
const fibonacci = |x|
  if x <= 1
  then 1
  else fibonacci(x - 1) + fibonacci(x - 2)

# 'universe' type used for I/O monad:
# 'print' has type String -> @ -> @, 'main' has type @ -> @
const main =
  print("Hello, world!")

const quicksort = |l|
  # foo:bar is infix notation for bar(foo)
  let pivot = l:nth(l:len / 2);
  # Operators can be curried
  let (left, mid, right) = (< pivot, = pivot, > pivot)
    .map(|cmp| l:filter(cmp))
  [left:quicksort, mid, right:quicksort]:fuse