good good study, day day up!

vendor/gopl.io/ch12/methods/methods.go

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+// Copyright © 2016 Alan A. A. Donovan & Brian W. Kernighan.
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+
+// See page 351.
+
+// Package methods provides a function to print the methods of any value.
+package methods
+
+import (
+	"fmt"
+	"reflect"
+	"strings"
+)
+
+//!+print
+// Print prints the method set of the value x.
+func Print(x interface{}) {
+	v := reflect.ValueOf(x)
+	t := v.Type()
+	fmt.Printf("type %s\n", t)
+
+	for i := 0; i < v.NumMethod(); i++ {
+		methType := v.Method(i).Type()
+		fmt.Printf("func (%s) %s%s\n", t, t.Method(i).Name,
+			strings.TrimPrefix(methType.String(), "func"))
+	}
+}
+
+//!-print

vendor/gopl.io/ch12/methods/methods_test.go

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+// Copyright © 2016 Alan A. A. Donovan & Brian W. Kernighan.
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+
+package methods_test
+
+import (
+	"strings"
+	"time"
+
+	"gopl.io/ch12/methods"
+)
+
+func ExamplePrintDuration() {
+	methods.Print(time.Hour)
+	// Output:
+	// type time.Duration
+	// func (time.Duration) Hours() float64
+	// func (time.Duration) Minutes() float64
+	// func (time.Duration) Nanoseconds() int64
+	// func (time.Duration) Seconds() float64
+	// func (time.Duration) String() string
+}
+
+func ExamplePrintReplacer() {
+	methods.Print(new(strings.Replacer))
+	// Output:
+	// type *strings.Replacer
+	// func (*strings.Replacer) Replace(string) string
+	// func (*strings.Replacer) WriteString(io.Writer, string) (int, error)
+}
+
+/*
+//!+output
+methods.Print(time.Hour)
+// Output:
+// type time.Duration
+// func (time.Duration) Hours() float64
+// func (time.Duration) Minutes() float64
+// func (time.Duration) Nanoseconds() int64
+// func (time.Duration) Seconds() float64
+// func (time.Duration) String() string
+
+methods.Print(new(strings.Replacer))
+// Output:
+// type *strings.Replacer
+// func (*strings.Replacer) Replace(string) string
+// func (*strings.Replacer) WriteString(io.Writer, string) (int, error)
+//!-output
+*/