Adding Reduce method to List class

list_reduce.go

package main

import "container/list"

type MyList struct {
  *list.List
}

func (l *MyList) Reduce(f func(interface{}, interface{}) interface{}) interface{} {
  s := l.Front()
  r := s.Value
  for e := s.Next(); e != nil; e = e.Next() {
    r = f(r, e.Value)
  }
  return r
}