examplefunc_test.go

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