Golang Display递归打印

《The Go Programming Language》笔记

Golang的反射由reflect包提供支持，有两个重要类型：一个Type表示一个Go类型，它是一个接口。一个Value可以持有任意类型的值。

import (
    "fmt"
    "reflect"
    "strconv"
)

func Display(name string, x interface{}) {
    fmt.Printf("Display %s (%T):\n", name, x)
    display(name, reflect.ValueOf(x))
}

func formatAtom(v reflect.Value) string {
    switch v.Kind() {
    case reflect.Invalid:
        return "invalid"
    case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32,
        reflect.Int64:
        return strconv.FormatInt(v.Int(), 10)
    case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32,
        reflect.Uint64:
        return strconv.FormatUint(v.Uint(), 10)
    case reflect.Bool:
        return strconv.FormatBool(v.Bool())
    case reflect.String:
        return strconv.Quote(v.String())
    case reflect.Chan, reflect.Func, reflect.Ptr, reflect.Slice, reflect.Map:
        return v.Type().String() + "0x" + strconv.FormatUint(uint64(v.Pointer()), 16)
    default:
        return v.Type().String() + "value"
    }
}

func display(path string, v reflect.Value) {
    switch v.Kind() {
    case reflect.Invalid:
        fmt.Printf("%s = invalid\n", path)
    case reflect.Slice, reflect.Array:
        for i := 0; i < v.Len(); i++ {
            display(fmt.Sprintf("%s[%d]", path, i), v.Index(i))
        }
    case reflect.Struct:
        for i := 0; i < v.NumField(); i++ {
            fieldPath := fmt.Sprintf("%s.%s", path, v.Type().Field(i).Name)
            display(fieldPath, v.Field(i))
        }
    case reflect.Map:
        for _, key := range v.MapKeys(){
            display(fmt.Sprintf("%s[%s]", path, formatAtom(key)), v.MapIndex(key))
        }
    case reflect.Ptr:
        if v.IsNil() {
            fmt.Printf("%s = nil\n", path)
        } else {
            display(fmt.Sprintf("*%s", path), v.Elem())
        }
    case reflect.Interface:
        if v.IsNil() {
            fmt.Printf("%s = nil\n", path)
        } else {
            fmt.Printf("%s.type = %s\n", path, v.Elem().Type())
            display(path+".value", v.Elem())
        }
    default:
        fmt.Printf("%s = %s\n", path, formatAtom(v))

    }
}

import "testing"

type Movie struct {
    Title, Subtitle string
    Year            int
    Color           bool
    Actor           map[string]string
    Oscars          []string
    Sequel          *string
}

var strangelove = Movie{
    Title:    "Dr. Strangelove",
    Subtitle: "How I Learned to Stop Worrying and Love the Bomb",
    Year:     1964,
    Color:    false,
    Actor: map[string]string{
        "Dr. Strangelove":           "Peter Sellers",
        "Grp. Cat. Lionel Mandrake": "Peter Sellers",
        "Gen. Buck Turgidson":       "George Hayden",
    },
    Oscars: []string{
        "Best Actor (Nomin.)",
        "Best Adapted Screeenplay (Nomin.)",
    },
}

func TestDisplay(t *testing.T) {
    Display("strangelove",strangelove)
}

Display strangelove (main.Movie):
strangelove.Title = “Dr. Strangelove”
strangelove.Subtitle = “How I Learned to Stop Worrying and Love the Bomb”
strangelove.Year = 1964
strangelove.Color = false
strangelove.Actor[“Dr. Strangelove”] = “Peter Sellers”
strangelove.Actor[“Grp. Cat. Lionel Mandrake”] = “Peter Sellers”
strangelove.Actor[“Gen. Buck Turgidson”] = “George Hayden”
strangelove.Oscars[0] = “Best Actor (Nomin.)”
strangelove.Oscars[1] = “Best Adapted Screeenplay (Nomin.)”
strangelove.Sequel = nil