hugo option 代码
文件路径：/tpl/internal/go_templates/texttemplate/option.go
/ 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 "strings"
/ 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 (t *Template) Option(opt ...string) *Template {
t.init()
for _, s := range opt {
t.setOption(s)
}
return t
}
func (t *Template) setOption(opt string) {
if opt == "" {
panic("empty option string")
}
/ key=value
if key, value, ok := strings.Cut(opt, "="); ok {
switch key {
case "missingkey":
switch value {
case "invalid", "default":
t.option.missingKey = mapInvalid
return
case "zero":
t.option.missingKey = mapZeroValue
return
case "error":
t.option.missingKey = mapError
return
}
}
}
panic("unrecognized option: " + opt)
}