functional operators

functional_operators.go

package main

import (
	"time"
)

type Server struct {
	addr string

	// default no timeout
	timeout time.Duration
}

// Timeout configures a maximum length of idle connection in Server
func Timeout(timeout time.Duration) func(*Server) {
	return func(s *Server) {
		s.timeout = timeout
	}
}

// NewServer initializes a new Server listening on addr with optional configuration
func NewServer(addr string, opts ...func(*Server)) *Server {
	server := &Server{
		addr: addr,
	}

	// apply the list of options to Server
	for _, opt := range opts {
		opt(server)
	}

	return server
}

func main() {
	// configure a timeout in addition to the address
	server := NewServer(":8080", Timeout(10*time.Second))
}