Copyright 2015 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.
This file contains the code to handle template options.

package template

import
missingKeyAction defines how to respond to indexing a map with a key that is not present.
type missingKeyAction int

const (
	mapInvalid   missingKeyAction = iota // Return an invalid reflect.Value.
	mapZeroValue                         // Return the zero value for the map element.
	mapError                             // Error out
)

type option struct {
	missingKey missingKeyAction
}
Option sets options for the template. Options are described by strings, either a simple string or "key=value". There can be at most one equals sign in an option string. If the option string is unrecognized or otherwise invalid, Option panics. Known options: missingkey: Control the behavior during execution if a map is indexed with a key that is not present in the map. "missingkey=default" or "missingkey=invalid" The default behavior: Do nothing and continue execution. If printed, the result of the index operation is the string "<no value>". "missingkey=zero" The operation returns the zero value for the map type's element. "missingkey=error" Execution stops immediately with an error.
func ( *Template) ( ...string) *Template {
	.init()
	for ,  := range  {
		.setOption()
	}
	return 
}

func ( *Template) ( string) {
	if  == "" {
		panic("empty option string")
	}
	 := strings.Split(, "=")
	switch len() {
key=value
		switch [0] {
		case "missingkey":
			switch [1] {
			case "invalid", "default":
				.option.missingKey = mapInvalid
				return
			case "zero":
				.option.missingKey = mapZeroValue
				return
			case "error":
				.option.missingKey = mapError
				return
			}
		}
	}
	panic("unrecognized option: " + )