为什么字段部分没有嵌入？

huangapple
go评论108阅读模式
英文:

Why the field section does not get embedded

问题

我有以下的结构体：

  1. package router
  3. import (
  4. 	"io"
  5. 	"net/http"
  6. 	"townspeech/components/i18n"
  7. 	"townspeech/components/policy"
  8. 	"townspeech/components/session"
  9. 	"townspeech/controllers/base"
  10. 	"townspeech/types"
  11. )
  13. type sidHandler struct {
  14. 	req     *http.Request
  15. 	res     http.ResponseWriter
  16. 	handler sidFuncHandler
  17. 	section string
  18. 	err     *types.ErrorJSON
  19. 	sess    *session.Sid
  20. }

我想将它嵌入到另一个结构体中，如下所示：

  1. package router
  3. import (
  4.     "net/http"
  5.     "townspeech/types"
  6.     "townspeech/components/session"
  7.     "townspeech/controllers/base"
  8. )
  10. type authHandler struct {
  11.     sidHandler
  12.     handler authFuncHandler
  13.     auth    *session.Auth
  14. }

并且使用authHandler结构体的函数：

  1. func registerAuthHandler(handler authFuncHandler, section string) http.Handler {
  2.     return &authHandler{handler: handler, section: section}
  3. }

编译器报错：

  1. # app/router
  2. ../../../router/funcs.go:9: unknown authHandler field 'section' in struct literal
  3. FAIL    app/test/account/validation [build failed]

如你所见，这两个结构体位于同一个包中，字段section不应该是私有的。我做错了什么？

英文:

I have the following struct

  1. package router
  3. import (
  4. 	"io"
  5. 	"net/http"
  6. 	"townspeech/components/i18n"
  7. 	"townspeech/components/policy"
  8. 	"townspeech/components/session"
  9. 	"townspeech/controllers/base"
  10. 	"townspeech/types"
  11. )
  13. type sidHandler struct {
  14. 	req     *http.Request
  15. 	res     http.ResponseWriter
  16. 	handler sidFuncHandler
  17. 	section string
  18. 	err     *types.ErrorJSON
  19. 	sess    *session.Sid
  20. }

And I want to embed in another struct like:

  1. package router
  3. import (
  4.     "net/http"
  5.     "townspeech/types"
  6.     "townspeech/components/session"
  7.     "townspeech/controllers/base"
  8. )
  10. type authHandler struct {
  11.     sidHandler
  12.     handler authFuncHandler
  13.     auth    *session.Auth
  14. }

And the function, that use the authHandler struct:

  1. func registerAuthHandler(handler authFuncHandler, section string) http.Handler {
  2.     return &authHandler{handler: handler, section: section}
  3. }

The compiler complain:

  1. # app/router
  2. ../../../router/funcs.go:9: unknown authHandler field 'section' in struct literal
  3. FAIL	app/test/account/validation [build failed]

As you can see, the two structs are in the same package, field section should not appear as private.
What am I doing wrong?

答案1

得分: 2

你不能在结构体字面值中引用提升的字段。你必须创建嵌入类型，并通过类型名称引用它。

  1. &authHandler{
  2. 	sidHandler: sidHandler{section: "bar"},
  3. 	handler:    "foo",
  4. }
英文:

You can't refer to promoted fields in a struct literal. You have to create the embedded type, and refer to it by the type's name.

  1. &authHandler{
  2. 	sidHandler: sidHandler{section: "bar"},
  3. 	handler:    "foo",
  4. }

答案2

得分: 2

嵌入式不适用于这样的文字。

  1. func registerAuthHandler(handler authFuncHandler, section string) http.Handler {
  2.     return &authHandler{
  3.         handler: handler,
  4.         sidHandler: sidHandler{section: section},
  5.     }
  6. }
英文:

Embedding doesn't work with literals like that.

  1. func registerAuthHandler(handler authFuncHandler, section string) http.Handler {
  2.     return &authHandler{
  3.         handler: handler,
  4.         sidHandler: sidHandler{section: section},
  5.     }
  6. }

huangapple
  • 本文由 发表于 2015年4月17日 02:25:32
  • 转载请务必保留本文链接：https://go.coder-hub.com/29683047.html
  • go
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