A statically typed, compiled programming language designed by Google designed to blend high performance networking, concurrency, memory safety and readability. It was first created in 2009 by Robert Griesemer, Rob Pike (Unix, Plan 9, UTF-8) and Ken Thompson (C, Unix).
It was borne from criticisms in other languages being used by Google at the time, with a particular shared dislike of C++.
Variables
Variables are 0 initialised, false for bool and "" for strings. Explicit types are used with the var name type
// explicit typing
var name string
name = "text"
// duck typing
name2 := "text"
const pi = 3.14
Types
Basic types:
bool
string
int int8 int16 int32 int64
uint uint8 uint16 uint32 uint64 uintptr
byte // alias for uint8
rune // alias for int32
// represents a Unicode code point
float32 float64
complex64 complex128
Casting:
i := 42
f := float64(i)
u := uint(f)
Type definitions:
type Page struct {
Title string
Body []byte
}
Control Structures
if
func pow(x, n, lim float64) float64 {
// if
if x < 0 {
return sqrt(-x) + "i"
}
// if with prefix statement
if v := math.Pow(x, n); v < lim {
// v is only in if scope
return v
}
}
for
func main() {
sum := 0
// for loop
for i := 0; i < 10; i++ {
sum += i
}
fmt.Println(sum)
// while loop
for sum < 1000 {
sum += sum
}
// infinite loop
for {
fmt.Println(sum)
}
}
switch
func main() {
switch os := runtime.GOOS; os {
case "darwin":
fmt.Println("OS X.")
case "linux":
fmt.Println("Linux.")
default:
// freebsd, openbsd,
// plan9, windows...
fmt.Printf("%s.\n", os)
}
// conditionaless switch for clean else if chains
switch {
case t.Hour() < 12:
fmt.Println("Good morning!")
case t.Hour() < 17:
fmt.Println("Good afternoon.")
default:
fmt.Println("Good evening.")
}
}
Interesting Constructs
Defer runs immediately after the function returns. The deferred call's arguments are evaluated immediately, but the function call is not executed until the surrounding function returns.
func main() {
defer fmt.Println("world")
fmt.Println("hello")
}