Exercising Go templates

go_templates.go

package main
import (
	"fmt"
	"html/template"
	"os"
	"strings"
)

type Person struct {
	Name string
	Age int
	Emails []string
	Jobs []*Job
}

type Job struct {
	Employer string
	Role string
}

const templ = `The name is {{.Name}}.
{{$name := .Name}}
The age is {{.Age}}
{{range .Emails}}An email is {{.}}
{{end}}-----------------------
{{range .Jobs}}{{$name}} is a {{.Role}} at {{if eq .Employer "Box Hill"}}{{.Employer | capitalize}}
{{else}}{{.Employer}}{{end}}
{{end}}`

func main() {
	// Create some data
	job1 := Job{Employer: "Monash", Role: "Honorary"}
	job2 := Job{Employer: "Box Hill", Role: "Head of HE"}
	person := Person {
		Name: "Jan",
		Age: 50,
		Emails: []string{"jan@123.com", "jan@345.com"},
		Jobs: []*Job{&job1, &job2},
	}

	t := template.New("Person template") // create a container
	t = t.Funcs(template.FuncMap{"capitalize" : Capitalizer}) // add our custom template function
	t, err := t.Parse(templ)	// load template data into the container
	checkError(err)

	err = t.Execute(os.Stdout, person) // apply an object to the template
	checkError(err)
}

// Custom pipeline function
func Capitalizer(args ...interface{}) string {
	ok := false
	var s string
	if len(args) == 1 {
		s, ok = args[0].(string)
	}
	if !ok {
		s = fmt.Sprint(args...)
	}
	return strings.ToUpper(s)
}

func checkError(err error) {
	if err != nil {
		fmt.Println("Fatal error", err.Error())
		os.Exit(1)
	}
}