Go 学习：day01

xcode-select --install

brew install go

go help

export GO111MODULE=on
export GOPROXY=https://goproxy.cn

go hello-world.go
Hello, World!

go get -u github.com/golangci/golangci-lint/cmd/golangci-lint

go get -u github.com/golangci/golangci-lint/cmd/golangci-lint

everfu@MacBook-Pro ~ % go help
Go is a tool for managing Go source code.

Usage:

	go <command> [arguments]

The commands are:

	bug         start a bug report
	build       compile packages and dependencies
	clean       remove object files and cached files
	doc         show documentation for package or symbol
	env         print Go environment information
	fix         update packages to use new APIs
	fmt         gofmt (reformat) package sources
	generate    generate Go files by processing source
	get         add dependencies to current module and install them
	install     compile and install packages and dependencies
	list        list packages or modules
	mod         module maintenance
	run         compile and run Go program
	test        test packages
	tool        run specified go tool
	version     print Go version
	vet         report likely mistakes in packages

Use "go help <command>" for more information about a command.

Additional help topics:

	buildconstraint build constraints
	buildmode       build modes
	c               calling between Go and C
	cache           build and test caching
	environment     environment variables
	filetype        file types
	go.mod          the go.mod file
	gopath          GOPATH environment variable
	gopath-get      legacy GOPATH go get
	goproxy         module proxy protocol
	importpath      import path syntax
	modules         modules, module versions, and more
	module-get      module-aware go get
	module-auth     module authentication using go.sum
	packages        package lists and patterns
	private         configuration for downloading non-public code
	testflag        testing flags
	testfunc        testing functions
	vcs             controlling version control with GOVCS

Use "go help <topic>" for more information about that topic.

package main

// 引入 go 的 I/O
import "fmt"

func main() {
    fmt.Println("Hello, World!")
}

package main

import "testing"

func TestHello(t *testing.T) {
    got := "Hello, World"
    want := "Hello, World"
    
    if got != want {
        t.Errorf("got %q want %q", got, want)
    }
}

go test
PASS
ok      efu.me/m        0.193s

func Hello(name string, language string) string {
	if name == "" {
		name = "World"
	}

	switch language {
		case spanish:
			helloPrefix = spanishHelloPrefix
		case french:
			helloPrefix = frenchHelloPrefix
	}

	return helloPrefix + name
}

// go 必须有一个 main 包，且必须有一个 main 函数作为程序的入口点
package main

// 导入 go 的 I/O 包
import "fmt"

const spanish = "Spanish"
const french = "French"
const helloPrefix = "Hello, "
const spanishHelloPrefix = "Hola, "
const frenchHelloPrefix = "Bonjour, "


func Hello(name string, language string) string {
	if name == "" {
		name = "World"
	}

	return greetingPrefix(language) + name
}

func greetingPrefix(language string) (prefix string) {
	switch language {
		case spanish:
			prefix = spanishHelloPrefix
		case french:
			prefix = frenchHelloPrefix
		default:
			prefix = helloPrefix
	}
	return
}

// main 函数
func main() {
	// 打印
	fmt.Println(Hello("world", "English"))
}

package main

import "testing"

func TestHello(t *testing.T) {
	t.Run("in Spanish", func(t *testing.T) {
		got := Hello("Elodie", "Spanish")
		want := "Hola, Elodie"

		if got != want {
			t.Errorf("got %q want %q", got, want)
		}
	})
	t.Run("in French", func(t *testing.T) {
		got := Hello("Elodie", "French")
		want := "Bonjour, Elodie"

		if got != want {
			t.Errorf("got %q want %q", got, want)
		}
	})
}