args.go

package main

import (
    "fmt"
    "os"
    "errors"
)

func NewNote(field string) (Note, error) {
    inst := Note{}
    inst.PublicField = 2
    return inst, inst.SetPrivateField(field)
}

type Note struct {
    PublicField int
    privateField string
}

func (n *Note) GetPrivateField() (string) {
    return n.privateField
}

func (n *Note) SetPrivateField(field string) (error) {
    err := n.ensurePrivateFieldLength(field)
    if err != nil {
        return err
    }
    n.privateField = field
    return nil
}

func (n *Note) ensurePrivateFieldLength(field string) (error) {
    if len(field) == 0 {
        return errors.New("Empty private field given!")
    }
    return nil
}

func main() {
    fmt.Printf("You have entered %v arguments:\n", len(os.Args))
    for i := 0; i < len(os.Args); i++ {
        fmt.Println(os.Args[i])
    }

    note, err := NewNote("my note")
    if err != nil {
        os.Exit(1)
    }
    fmt.Println(note.PublicField)
    fmt.Println(note.GetPrivateField())

    var notepointer *Note
    notepointer = &note
    fmt.Println(notepointer.PublicField)
    fmt.Println(notepointer.GetPrivateField())

    os.Exit(0)
}