Golo supports a compact form of closures for the cases where their body consists of a single expression. The example above can be simplified as:

let adder = |a, b| -> a + b

You may also use this compact form when defining regular functions, as in:

module Foo

local function sayHello = |who| -> "Hello " + who + "!"

# Prints "Hello Julien!"
function main = |args| {
  println(sayHello("Julien"))
}