Implementation of a Fibonacci Closure in Go. Part of the Go tour: http://tour.golang.org/#43

FibonacciClosure.go

package main

import "fmt"

// fibonacci is a function that returns
// a function that returns an int.
func fibonacci() func() int {
    var m1, m2 int
    return func() int {
        res := m1 + m2
        m2 = m1
        m1 = res
        
        if res == 0 {
            m2 = 1    // Because printing the full sequence is hot
        }
        
        return res
    }
}

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