package main

import (
	"fmt"
	"html/template"
	"os"
)

func main() {
	tplstr := "hello {{myFunc}}\n"

	fmap := template.FuncMap{}
	fmap["myFunc"] = func() (string, error) {
		return "world", fmt.Errorf("hi")
	}

	tpl, err := template.New("demo").Funcs(fmap).Parse(tplstr)
	if err != nil {
		panic(fmt.Errorf("Error creating template: %v", err))
	}

	err = tpl.Execute(os.Stdout, nil)
	if err != nil {
		panic(err)
	}
}