如何更改方法內的函數引用字段？

Question

type FuncPtr func(int) int 

func Foo(i int) { return i * i } 

type Events struct { 
    SomeFunc FuncPtr 
} 

type Top struct { 
    events Events 
} 

func (self *Top) initEvents() { 
    // This change works within this function, but 
    // doesn't stick around after this method returns. 
    self.events.SomeFunc = Foo 
} 

func main() { 
    var t := Top{} 
    t.initEvents() 
    t.events.SomeFunc == nil // True: Change in initEvents() doesn't stick 
} 

如何使initEvents()方法中的更改持續存在？也就是說，我想在initEvents()方法中更改函數引用Top::Events::SomeFunc的值，並且一旦initEvents()方法返回，該更改將繼續。

Answer 1

你有一些小的更正，使其可編譯的代碼工作。

1. 有頂部
2. 沒有包聲明你沒有指定一個整數返回類型爲你的函數foo

我已經包含代碼的完整示例下面爲了方便，如果你想這個運行自己，你可以做到這一點：https://play.golang.org/p/Ngu8FFiGrI

package main 

import(
    "fmt" 
) 

type FuncPtr func(int) int 

func Foo(i int) int { 
    return i*i 
} 

type Events struct { 
    SomeFunc FuncPtr 
} 

type Top struct { 
    events Events 
} 

func (self *Top) initEvents() { 
    // This change works within this function, but 
    // doesn't stick around after this method returns. 
    self.events.SomeFunc = Foo 
} 

func main() { 
    var t = Top{} 
    t.initEvents() 
    if t.events.SomeFunc == nil { 
    fmt.Println("SomeFunc not set") 
    } 
    fmt.Println("6^2 =",t.events.SomeFunc(6)) 
}