Command handling dependency injection

chdi.go

package cmd

import "fmt"

type Cmd struct {
	trigger string
	handler CmdHandler
}

type CmdHandler interface {
	Name() string // return a string describing command name
	Register(string) []byte // Register a command by name
}

func NewCmd(ch CmdHandler) *Cmd {
	return &Cmd {
		trigger: []byte("Trigger for command " + ch.Name),
		handler: ch,	
	}
}

func (c *Cmd) Register(name string) {
	c.trigger = c.handler.Register(name)
}

commands.go

type Commands struct {
	cmds map[string][]byte
}

func NewCommand() *Commands {
	return &Commands {
		cmds: map[string][byte]{},
	}
}

func (c *Commands) Register(name string, handler []byte) {
	c.cmds[name] = handler
}

func (c *Commands) Name() string {
	return "Command"
}

main.go

func main() {
	theo := NewCommand()
	cmd := NewCmd(theo)
	cmd.handler.Register("theo command")
}