Solution to the fibonacci problem using function closures in go http://tour.golang.org/#44

fibonacci.go

package main

import "fmt"

// fibonacci is a function that returns
// a function that returns an int.
func fibonacci() func() int {
    current := 0
    a := 0
    b := 1
    return func() int {
        current, a, b = a, b, a+b
        return current
    }
}

func main() {
    f := fibonacci()
    for i := 0; i < 10; i++ {
        fmt.Println(f())
    }
}