; call an external function directly
call.external: "mylib" 'sayHello ["John"]

; map an external function to a native one
doubleNum: function [num][
    ensure -> integer? num
    call .external: "mylib"
         .expect:   :integer
         'doubleNum @[num]
]

loop 1..3 'x [
    print ["The double of" x "is" doubleNum x]
]