frankpf

    type Email = distinct string

   # I'm raising an exception, but you could use an option or a result type
   proc validateEmail(str: string): Email =
      if email.contains("@"):
          return Email(str)
      raise newException(InvalidEmail, "not valid")

    proc createUser(email: Email, password: Password) =
       ...

    proc safeDivide(a: int, b: int): float {.requires b > 0.} =
        a / b

    var x = stdin.readLine.parseInt
    safeDivide(1, x) # DrNim will error at compile-time 
    var y = stdin.readLine.parseInt
    if y > 20:
       # no error since DrNim (using Z3) can
       # prove that y is always greater than 0 here
       safeDivide(1, y)

   require('npm/validatePackageVersions') # or import 'npm/...' in es6

    A
    => depends on B @ 1.0
    => depends on C, and C can depend on B @ 2.0

    (defn greet [firstname lastname]
      (def fullname (string firstname " " lastname))
      (string "Hello, " fullname))

    (defn greet [firstname lastname]
      (let [fullname (string firstname " " lastname)]
        (string "Hello, " fullname)))

    const ContactInfo = t.type({
       address_1: t.string,
       ...
    })

    type ContactInfo = t.TypeOf<typeof ContactInfo>

    knex.insert({ bar: 'bar', baz: 'baz' }).into('foo')