XProduct

Creates a new slice out of the two supplied by creating each possible pair from the collections.

• Use reflect.ValueOf() to get the arrays or slices, Value.Len() and make() to create an appropriate slice for the result.
• Use a for loop with Value.Len(), Value.Index() and Value.Interface() to populate the result.

import "reflect"

func XProduct(params ...interface{}) [][]interface{} {
    a, b := reflect.ValueOf(params[0]), reflect.ValueOf(params[1])
    l := a.Len() * b.Len()
    r := make([][]interface{}, l)

    for i := 0; i < l; i++ {
        r[i] = []interface{}{
            a.Index(i % a.Len()).Interface(),
            b.Index((i / a.Len()) % b.Len()).Interface(),
        }
    }
    return r

}

XProduct([]int{1, 2}, []string{"a", "b"}) // [[1 a] [2 a] [1 b] [2 b]]