examplefunc_test.go (1601B)
1 // Copyright 2012 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
4
5 //go:build go1.13
6 // +build go1.13
7
8 package template_test
9
10 import (
11 "log"
12 "os"
13 "strings"
14 "text/template"
15 )
16
17 // This example demonstrates a custom function to process template text.
18 // It installs the strings.Title function and uses it to
19 // Make Title Text Look Good In Our Template's Output.
20 func ExampleTemplate_func() {
21 // First we create a FuncMap with which to register the function.
22 funcMap := template.FuncMap{
23 // The name "title" is what the function will be called in the template text.
24 "title": strings.Title,
25 }
26
27 // A simple template definition to test our function.
28 // We print the input text several ways:
29 // - the original
30 // - title-cased
31 // - title-cased and then printed with %q
32 // - printed with %q and then title-cased.
33 const templateText = `
34 Input: {{printf "%q" .}}
35 Output 0: {{title .}}
36 Output 1: {{title . | printf "%q"}}
37 Output 2: {{printf "%q" . | title}}
38 `
39
40 // Create a template, add the function map, and parse the text.
41 tmpl, err := template.New("titleTest").Funcs(funcMap).Parse(templateText)
42 if err != nil {
43 log.Fatalf("parsing: %s", err)
44 }
45
46 // Run the template to verify the output.
47 err = tmpl.Execute(os.Stdout, "the go programming language")
48 if err != nil {
49 log.Fatalf("execution: %s", err)
50 }
51
52 // Output:
53 // Input: "the go programming language"
54 // Output 0: The Go Programming Language
55 // Output 1: "The Go Programming Language"
56 // Output 2: "The Go Programming Language"
57 }