Understanding Reflect Package in Golang

A sample code written in #golang to understand the reflect package and the interfaces. You can try running the code on http://play.golang.org

	package main
	import (
	"fmt"
	"reflect"
	)
	func main() {
	var nano car = car{5}
	var donkey animal
	var what somethingMakesCommon
	what = &donkey
	fmt.Printf("\n==============================\n")
	fmt.Printf("\nAnimal %v", donkey)
	fmt.Printf("\nCar %v", nano)
	fmt.Printf("\nSomeInterface %v", what)
	fmt.Printf("\n==============================\n")
	what.Bark(2)
	cntr = reflect.TypeOf(what).NumMethod()
	fmt.Printf("\n No. of methods %v", cntr)
	obj := reflect.ValueOf(what)
	for i := 0; i < cntr; i++ {
	methodstr := reflect.TypeOf(what).Method(i).Name
	nargs := reflect.TypeOf(what).Method(i).Type.NumIn()
	fmt.Printf("\n Name of the method %v", methodstr)
	fmt.Printf("\n No. of Arguments of the method %v is %#v", methodstr, nargs-1)
	fmt.Printf("\n No. of Arguments of the method %v is %v", methodstr, reflect.TypeOf(what).Method(i))
	//fmt.Printf("\nIs valid to call %v", reflect.ValueOf(what).Method(i).IsValid())
	fmt.Printf(" ... Szzz trying to call ")
	// in := make([]reflect.Value, nargs)
	nargs = obj.Method(i).Type().NumIn()
	args := make([]reflect.Value, nargs)
	// args[0].SetInt(5)
	for j := 0; j < nargs; j++ {
	var para int = 5
	args[j] = reflect.ValueOf(para)
	// fmt.Printf("\n ARG %v", reflect.TypeOf(what).Method(i).Type.In(j))
	// // reflect.TypeOf(what).Method(i).Type.In(j) = 5
	// args[j] = reflect.ValueOf(what).Method(i)
	}
	outvals := reflect.ValueOf(what).Method(i).Call(args)
	fmt.Printf(".. Worked ?? Output of %s", methodstr)
	for indx, val := range outvals {
	fmt.Printf("\n OUTPUT %d : %v", indx, val.Interface())
	}
	}
	// fmt.Printf(
	}
	type somethingMakesCommon interface {
	Bark(int) []string
	}
	type car struct {
	wheels int
	}
	func (c *car) Bark(times int) []string {
	for i := 0; i < times; i++ {
	fmt.Printf("\nBeep..")
	}
	return []string{"Tata", "Motors"}
	}
	func (c car) Sleep() {
	fmt.Printf("----I can sleep by turn off---")
	}
	func (a animal) Sleep() {
	fmt.Printf("---I can sleep---")
	}
	func (a *animal) Bark(times int) []string {
	for i := 0; i < times; i++ {
	fmt.Printf("\nBeep..")
	}
	return []string{"meow"}
	}
	type animal struct {
	legs int
	tail float32
	}

view raw reflectexample.go hosted with ❤ by GitHub

Go Lang - Quick Setup

I had almost written this post two weeks back using the wordpress mobile client on my #samsung note stylus (handwriting mode) during a train travel. Though the client indicated that the post is saved as draft on the mobile client, it never uploaded to the server and I lost all my content. Coming back to the post, the intention of this post is for someone who has decent knowledge of C/C++ programming and wants to give a try to #golang.