[Go] Higher-order function: filter.

package main

import (
    "log"
)

func filter(arr []int, predicate func(int) bool) []int {
    out := make([]int, 0)

    for _, e := range arr {
        if predicate(e) {
            out = append(out, e)
        }
    }

    return out
}

func eq(m []int, n []int) bool {
    if len(m) != len(n) {
        return false
    }

    for i := 0; i < len(m); i++ {
        if m[i] != n[i] {
            return false
        }
    }

    return true
}

func main() {
    arr := []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}

    out := filter(arr, func(n int) bool { return n%2 == 0 })

    if !eq(out, []int{2, 4, 6, 8, 10}) {
        log.Fatal("Wrong value")
    }
}