60 lines
1.5 KiB
Go
60 lines
1.5 KiB
Go
// Copyright 2018 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package fmt_test
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import (
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"fmt"
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)
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// Address has a City, State and a Country.
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type Address struct {
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City string
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State string
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Country string
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}
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// Person has a Name, Age and Address.
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type Person struct {
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Name string
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Age uint
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Addr *Address
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}
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// GoString makes Person satisfy the GoStringer interface.
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// The return value is valid Go code that can be used to reproduce the Person struct.
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func (p Person) GoString() string {
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if p.Addr != nil {
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return fmt.Sprintf("Person{Name: %q, Age: %d, Addr: &Address{City: %q, State: %q, Country: %q}}", p.Name, int(p.Age), p.Addr.City, p.Addr.State, p.Addr.Country)
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}
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return fmt.Sprintf("Person{Name: %q, Age: %d}", p.Name, int(p.Age))
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}
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func ExampleGoStringer() {
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p1 := Person{
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Name: "Warren",
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Age: 31,
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Addr: &Address{
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City: "Denver",
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State: "CO",
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Country: "U.S.A.",
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},
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}
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// If GoString() wasn't implemented, the output of `fmt.Printf("%#v", p1)` would be similar to
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// Person{Name:"Warren", Age:0x1f, Addr:(*main.Address)(0x10448240)}
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fmt.Printf("%#v\n", p1)
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p2 := Person{
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Name: "Theia",
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Age: 4,
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}
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// If GoString() wasn't implemented, the output of `fmt.Printf("%#v", p2)` would be similar to
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// Person{Name:"Theia", Age:0x4, Addr:(*main.Address)(nil)}
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fmt.Printf("%#v\n", p2)
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// Output:
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// Person{Name: "Warren", Age: 31, Addr: &Address{City: "Denver", State: "CO", Country: "U.S.A."}}
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// Person{Name: "Theia", Age: 4}
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}
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