存储通用函数

Question

I would like to do something like this, but apparently it is not possible in this way, I think that there is something I miss.

type command struct {                                                            
    help string                                                                  
    handler func (params ...interface{})                                         
}                                                                                

func showHelp( commands map[string]command ) {                                   
    fmt.Println( "Help:" )                                                       
    for c, h := range commands {                                                 
        fmt.Println( c,"->" ,h.help )                                            
    }                                                                            
}                                                                                

func main() {                                                                
    // Map to store commands                                                     
    commands := make( map[string]command )                                       

    // Adding help command                                                       
    commands["help"] = command{ "show this information", showHelp }
}

Answer 1

You have a type mismatch in that your struct member expects an func(param ...interface) and you are trying to pass it a func(map[string]command)

See here for the explanation on how interface types work.

If you change your code as below and give the struct member simply type interface{} it can take any type including a function which I think is what you want.

package main

import "fmt"

type command struct {
    help    string
    handler interface{}
}

func showHelp(commands map[string]command) {
    fmt.Println("Help:")
    for c, h := range commands {
        fmt.Println(c, "->", h.help)
    }
}

func main() {
    // Map to store commands
    commands := make(map[string]command)

    // Adding help command
    commands["help"] = command{"show this information", showHelp}
    showHelp(commands)
}

Try in on the Go Playground