go is fucking shit

package main

import (
    "flag"
    "fmt"
    "os"
)

const (
    choke = iota
    unchoke
    interested
    not_intereste
    have
    bitfield
    request
    piece
    cancel
)

type Element interface{}

func buncode(in *os.File) (e Element) {
    var c [1]byte
    n, err := in.Read(c[:])
    if err != nil {
        panic(err)
    }
    if n == 0 {
        return nil
    }
    switch c[0] {
    case 'd':
        e = make(map[string]interface{})
        for {
            var k string = buncode(in).(string)
            v := buncode(in)
            e[k] = v
        }
        return
    case 'l':
        return "list"
    case 'i':
        return "int"
    default:
        panic("unknown type specified")
    }
    return nil
}

func main() {
    port := flag.Uint("port", 6881, "listen port for peers")
    flag.Parse()
    torrent_file := flag.Arg(0)
    if flag.NArg() > 2 {
        fmt.Println("Too many arguments")
        os.Exit(2)
    }
    fmt.Println("port is", *port, "torrent file at", torrent_file)
    file, err := os.Open(torrent_file)
    if err != nil {
        panic(err.String())
    }
    fmt.Println(buncode(file))
}