go by example scaffold thing

scaffold.go

package main

import (
	"fmt"
	"io/ioutil"
	"net/http"
	"os"
	"regexp"
)

var fileTemplate = `
package main

import "fmt"

func main() {
}
`
var directoryFormat = "./examples/%02d-%s"
var fileFormat = "%s/main.go"
var expr = regexp.MustCompile(`<li><a href="([\w-]+)">`)

func main() {
	html, err := request("https://gobyexample.com/")
	check(err)

	matches := expr.FindAllStringSubmatch(html, -1)
	for i, name := range matches {
		dirname := fmt.Sprintf(directoryFormat, i+1, name[1])
		filename := fmt.Sprintf(fileFormat, dirname)

		err := os.MkdirAll(dirname, 0777)
		check(err)

		fp, err := os.Create(filename)
		check(err)

		_, err = fp.WriteString(fileTemplate)
		check(err)

		defer fp.Close()
	}
}

func check(e error) {
	if e != nil {
		panic(e)
	}
}

func request(url string) (string, error) {
	res, err := http.Get(url)
	if err != nil {
		return "", err
	}

	defer res.Body.Close()

	body, err := ioutil.ReadAll(res.Body)
	if err != nil {
		return "", err
	}

	html := string(body)

	return html, nil
}