How do I make this Fibonacci sequence generator more elegant?

Question

package main

import "fmt"

func fib_seq() func() int {
    n0, n1 := 0, 1

    return func() int {
        result := n0
        n0, n1 = n1, n0 + n1
        return result
    }
}

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

This is my Fibonacci sequence generator. The definition of result is unwanted (but necessary).

I wonder is there a way to execute x, y = y, x + y after return?

Answer 1

You may want to take a look at defer:

func fib_seq() func() int {
    n0, n1 := 0, 1

    return func() int {
        defer func() {
            n0, n1 = n1, n0 + n1
        }()

        return n0
    }
}

Answer 2

Named return. But what you have is already readable enough.

func fib_seq() func() int {
    n0, n1 := 0, 1

    return func() (r int) {
        r, n0, n1 = n0, n1, n0 + n1
        return
    }
}