templatesfunc.go

package main

import (
	"text/template"
	"os"
	"log"
	"strings"
)

type Paragraph struct {
  Title string
  UpperCaseSentence string
  LowerCaseSentence string
}
	
func main() {
	funcMap := template.FuncMap{
      "ToUpper": strings.ToUpper,
      "ToLower": strings.ToLower,
      "ToTitle": strings.Title,
  }
	
	const sample = `
	{{.Title | ToTitle}}
	{{.UpperCaseSentence | ToUpper}}
	{{.LowerCaseSentence | ToLower}}
	`
	
	t := template.Must(template.New("sampleTest").Funcs(funcMap).Parse(sample))
	
	p := Paragraph{
		Title: "this is a title",
		UpperCaseSentence: "this is an upper case sentence",
		LowerCaseSentence: "THIS IS A LOWER CASE SENTENCE",
	}
	err := t.Execute(os.Stdout, p)
	if err != nil {
		log.Println(err.Error())
	}	
}