• If a closure has dynamic extent,
  • Then the variables it references are available
  • even after the scope of the variables is gone

def make_counter() {
    n = 0
    c = { n += 1; n }
    c
}

counter = make_counter()
println(counter.call())  # => 1
println(counter.call())  # => 2
println(counter.call())  # => 3

• This is a little like returning a pointer to a local variable
  • Except that it works!