Sample enableIf in Go

enable_if.go

package main

import "log"

// types.
type Fn func(id string, name string) error

// actions.
func Insert(id string, name string) error {
	log.Println("Insert ID:", id, " Name:", name)
	return nil
}
func Update(id string, name string) error {
	log.Println("Update ID:", id, " Name:", name)
	return nil
}
func Delete(id string, name string) error {
	log.Println("Delete ID:", id, " Name:", name)
	return nil
}
func Select(id string, name string) error {
	log.Println("Select ID:", id, " Name:", name)
	return nil
}

// Pipeline.
type Action struct {
	Name string
	Fn   Fn
}

var Pipeline = []Action{
	{Name: "add_user", Fn: Insert},
	{Name: "select_user", Fn: EnableIf(Select)},
	{Name: "update_user", Fn: Update},
	{Name: "select_user", Fn: EnableIf(Select)},
	{Name: "delete_user", Fn: Delete},
}

// enable if
// If ID:20 and Name:Root, then enable Select action!
func EnableIf(fn Fn) Fn {
	return func(id string, name string) error {
		if id == "20" && name == "Root" {
			return fn(id, name)
		}
		return nil
	}
}

func main() {
	for _, action := range Pipeline {
		if err := action.Fn("20", "Root"); err != nil {
			log.Println("Action:", action.Name, " failed!")
			return
		} else {
			log.Println("Action:", action.Name, " succeed!")
		}
	}
}