英文:
Closures in Go - declaring functions that take functions as parameters
问题
我一直在尝试弄清楚为什么这段代码不起作用，但不确定。沙盒中的错误是：
main.go:16: 语法错误：意外的 {，期望 )
代码：
package main
import "fmt"
type handler func(a func(b int))
func HandleSomething(h handler) {
//...
//d := h(5)
//h(5)
// ...
}
func main() {
var foo int
HandleSomething(handler(func(func(b int){
fmt.Printf("debug: foo in main is %d and %d", foo, b)
})))
}
英文:
I've been trying to figure out why this is not working but am not sure. The error in the sandbox is
main.go:16: syntax error: unexpected {, expecting )
Code:
package main
import "fmt"
type handler func(a func(b int))
func HandleSomething(h handler) {
//...
//d := h(5)
//h(5)
// ...
}
func main() {
var foo int
HandleSomething(handler(func(func(b int){
fmt.Printf("debug: foo in main is %d and %d", foo, b)
})))
}
答案1
得分: 0
看一下为什么它无法编译可能会有帮助，将最内层的函数提取为一个参数，如 https://play.golang.org/p/QPBturZ6GG 所示。
我认为你可能在寻找以下类似的内容，但它不会做太多事情 https://play.golang.org/p/2tEEwoZRC6
package main
import "fmt"
type handler func(a func(b int))
func HandleSomething(h handler) {
//...
//d := h(5)
//h(5)
// ...
}
func main() {
var foo int
HandleSomething(handler(func(a func(b int)) {
//这没有意义，因为你无法访问b
//fmt.Printf("debug: foo in main is %d and %d", foo, b)
fmt.Printf("debug: foo in main is %d", foo)
//你可以调用你的函数参数，如下所示
a(6)
a(7)
}))
}
以下示例可能会给你更多的玩耍空间
https://play.golang.org/p/BuxA8JXibG
英文:
To see why it won't compile it might be helpful to pull your innermost function out into an argument as shown at https://play.golang.org/p/QPBturZ6GG
I think you are looking for something like the following, but it won't do much
https://play.golang.org/p/2tEEwoZRC6
package main
import "fmt"
type handler func(a func(b int))
func HandleSomething(h handler) {
//...
//d := h(5)
//h(5)
// ...
}
func main() {
var foo int
HandleSomething(handler(func(a func(b int)) {
//This doesn't make sense as you don't have access to b
//fmt.Printf("debug: foo in main is %d and %d", foo, b)
fmt.Printf("debug: foo in main is %d", foo)
//You can call your function argument like
a(6)
a(7)
}))
}
The following example might give you something more to play with
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