Function DefaultPrintHelpCustom

help.go:376–463

DefaultPrintHelpCustom is the default implementation of HelpPrinterCustom. The customFuncs map will be combined with a default template.FuncMap to allow using arbitrary functions in template rendering.

(out io.Writer, templ string, data any, customFuncs map[string]any)

// The customFuncs map will be combined with a default template.FuncMap to
// allow using arbitrary functions in template rendering.
func DefaultPrintHelpCustom(out io.Writer, templ string, data any, customFuncs map[string]any) {
	const maxLineLength = 10000

	tracef("building default funcMap")
	funcMap := template.FuncMap{
		"join":           strings.Join,
		"subtract":       subtract,
		"indent":         indent,
		"nindent":        nindent,
		"trim":           strings.TrimSpace,
		"wrap":           func(input string, offset int) string { return wrap(input, offset, maxLineLength) },
		"offset":         offset,
		"offsetCommands": offsetCommands,
	}

	if wa, ok := customFuncs["wrapAt"]; ok {
		if wrapAtFunc, ok := wa.(func() int); ok {
			wrapAt := wrapAtFunc()
			customFuncs["wrap"] = func(input string, offset int) string {
				return wrap(input, offset, wrapAt)
			}
		}
	}

	for key, value := range customFuncs {
		funcMap[key] = value
	}

	w := tabwriter.NewWriter(out, 1, 8, 2, ' ', 0)
	t := template.Must(template.New("help").Funcs(funcMap).Parse(templ))

	if _, err := t.New("helpNameTemplate").Parse(helpNameTemplate); err != nil {
		handleTemplateError(err)
	}

	if _, err := t.New("argsTemplate").Parse(argsTemplate); err != nil {
		handleTemplateError(err)
	}

	if _, err := t.New("usageTemplate").Parse(usageTemplate); err != nil {
		handleTemplateError(err)
	}

	if _, err := t.New("descriptionTemplate").Parse(descriptionTemplate); err != nil {
		handleTemplateError(err)
	}

	if _, err := t.New("visibleCommandTemplate").Parse(visibleCommandTemplate); err != nil {
		handleTemplateError(err)
	}

	if _, err := t.New("copyrightTemplate").Parse(copyrightTemplate); err != nil {
		handleTemplateError(err)
	}

	if _, err := t.New("versionTemplate").Parse(versionTemplate); err != nil {
		handleTemplateError(err)
	}