Ejercicio 1

map.go

package main

import (
	"log"
	"reflect"
)

// Implements map by closure

type Mapper func(interface{}) interface{}

func Map(data []interface{}, fn Mapper) []interface{} {
	l := len(data)
	for i:=0; i<l; i++ {
		data[i] = fn(data[i])
	}
	return data
}

// Implements map by composition

type Enumerator interface {
	Map(interface{}) interface{}
}

func EnumeratorMap(data Enumerator) interface{} {
	t := reflect.ValueOf(data)
	arr := make([]interface{}, t.Len())

	for i:=0; i<t.Len(); i++ {
		arr[i] = data.Map(t.Index(i).Interface())
	}

	return arr
}

type T []int
func (t T) Map(datum interface{}) interface{} { return datum.(int)*2 }

func main() {
	// By composition
	t := T{1,2,3}
	results := EnumeratorMap(t)
	log.Println(results)

	// By closure
	results = Map([]interface{}{"a", "b", "c"}, func(datum interface{}) interface{} {
		return interface{}("PREY" + datum.(string))
	})
	log.Println(results)
}