http://neverwork.in/go-scalable-permutations/

quickperm.go

package main

import (  
    "fmt"
)

func main() {  
    for perm := range GeneratePermutations([]int{1,2,3,4,5,6,7}){
        fmt.Println(perm)
    }
}
func GeneratePermutations(data []int) <-chan []int {  
    c := make(chan []int)
    go func(c chan []int) {
        defer close(c) 
        permutate(c, data)
    }(c)
    return c 
}
func permutate(c chan []int, inputs []int){  
    output := make([]int, len(inputs))
    copy(output, inputs)
    c <- output

    size := len(inputs)
    p := make([]int, size + 1)
    for i := 0; i < size + 1; i++ {
        p[i] = i;
    }
    for i := 1; i < size;{
        p[i]--
        j := 0
        if i % 2 == 1 {
            j = p[i]
        }
        tmp := inputs[j]
        inputs[j] = inputs[i]
        inputs[i] = tmp
        output := make([]int, len(inputs))
        copy(output, inputs)
        c <- output
        for i = 1; p[i] == 0; i++{
            p[i] = i
        }
    }
}