text/template: add example for Template

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5564050

src/pkg/text/template/example_test.go

+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package template_test
+
+import (
+	"log"
+	"os"
+	"text/template"
+)
+
+// Dear Aunt Mildred,
+// 
+// It was a pleasure to see you at the wedding.
+// Thank you for the lovely bone china tea set.
+// 
+// Best wishes,
+// Josie
+// 
+// Dear Uncle John,
+// 
+// It is a shame you couldn't make it to the wedding.
+// Thank you for the lovely moleskin pants.
+// 
+// Best wishes,
+// Josie
+// 
+// Dear Cousin Rodney,
+// 
+// It is a shame you couldn't make it to the wedding.
+// 
+// Best wishes,
+// Josie
+func ExampleTemplate() {
+	// Define a template.
+	const letter = `
+Dear {{.Name}},
+{{if .Attended}}
+It was a pleasure to see you at the wedding.{{else}}
+It is a shame you couldn't make it to the wedding.{{end}}
+{{with .Gift}}Thank you for the lovely {{.}}.
+{{end}}
+Best wishes,
+Josie
+`
+
+	// Prepare some data to insert into the template.
+	type Recipient struct {
+		Name, Gift string
+		Attended   bool
+	}
+	var recipients = []Recipient{
+		{"Aunt Mildred", "bone china tea set", true},
+		{"Uncle John", "moleskin pants", false},
+		{"Cousin Rodney", "", false},
+	}
+
+	// Create a new template and parse the letter into it.
+	t := template.Must(template.New("letter").Parse(letter))
+
+	// Execute the template for each recipient.
+	for _, r := range recipients {
+		err := t.Execute(os.Stdout, r)
+		if err != nil {
+			log.Println("executing template:", err)
+		}
+	}
+}