英文:
Simplify casting in Go when taking any interface as a parameter
问题
我有一个类似这样的结构体：
//
// HandlerInfo 用于在功能中注册网关处理程序
type HandlerInfo struct {
Fn func(interface{})
FnName string
FnRm func()
}
我想传递一个函数：
func StarboardReactionHandler(e *gateway.MessageReactionAddEvent) {
// foo
}
i := HandlerInfo{Fn: StarboardReactionHandler}
不幸的是，这会导致以下错误：
无法将 'StarboardReactionHandler'（类型为 func(e *gateway.MessageReactionAddEvent)）用作类型为 func(interface{}) 的类型
我找到了这个解决方法：
func StarboardReactionHandler(e *gateway.MessageReactionAddEvent) {
// foo
}
func handlerCast(e interface{}) {
StarboardReactionHandler(e.(*gateway.MessageReactionAddEvent))
}
i := HandlerInfo{Fn: handlerCast}
有没有办法简化需要 handlerCast 的过程，比如在 StarboardReactionHandler 或 HandlerInfo 中进行处理？也许可以使用泛型或反射？我基本上只想尽量减少这里所需的语法/样板代码。
英文:
I have a struct like so,
//
// HandlerInfo is used by features in order to register a gateway handler
type HandlerInfo struct {
Fn func(interface{})
FnName string
FnRm func()
}
where I want to pass a func:
func StarboardReactionHandler(e *gateway.MessageReactionAddEvent) {
// foo
}
i := HandlerInfo{Fn: StarboardReactionHandler}
Unfortunately, this results in:
Cannot use 'StarboardReactionHandler' (type func(e *gateway.MessageReactionAddEvent)) as the type func(interface{})
I found this workaround:
func StarboardReactionHandler(e *gateway.MessageReactionAddEvent) {
// foo
}
func handlerCast(e interface{}) {
StarboardReactionHandler(e.(*gateway.MessageReactionAddEvent))
}
i := HandlerInfo{Fn: handlerCast}
Is there some way that I can simplify needing handlerCast, such as doing it inside my StarboardReactionHandler or in HandlerInfo? Maybe with generics or reflection? I basically just want to minimize the syntax / boilerplate that's required here.
答案1
得分: 0
你可以使用interface{}.(type)来进行类型断言。
以下是一个示例：
package main
import "fmt"
type HandlerInfo struct {
Fn func(interface{})
FnName string
FnRm func()
}
type MessageReactionAddEvent = func(a, b int) int
func StarboardReactionHandler(e interface{}) {
switch e.(type) {
case MessageReactionAddEvent:
fmt.Printf("%v\n", (e.(MessageReactionAddEvent))(1, 2))
}
}
func add(a, b int) int {
return a + b
}
func main() {
i := HandlerInfo{Fn: StarboardReactionHandler}
i.Fn(add)
}
希望对你有帮助！
英文:
you can use interface{}.(type)
follow is a exmple:
package main
import "fmt"
type HandlerInfo struct {
Fn func(interface{})
FnName string
FnRm func()
}
type MessageReactionAddEvent = func(a, b int) int
func StarboardReactionHandler(e interface{}) {
switch e.(type) {
case MessageReactionAddEvent:
fmt.Printf("%v\n", (e.(MessageReactionAddEvent))(1, 2))
}
}
func add(a, b int) int {
return a + b
}
func main() {
i := HandlerInfo{Fn: StarboardReactionHandler}
i.Fn(add)
}
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