// Outside a function, every statement begins with a keyword (var, func, and so on) and so the := construct is not available.
  var a int
  var a, b int
  var i,j int = 1, 2
 
 
  var x int = 3
  // Inside a function, the := short assignment statement can be used in place of a var declaration with implicit type.
  y := 3
 

The expression T(v) converts the value v to the type T. Unlike in C, in Go assignment between items of different type requires an explicit conversion.

i := 42
f := float64(i)
u := uint(f)

t := i.(T)

This statement asserts that the interface value i holds the concrete type T and assigns the underlying T value to the variable t. If i does not hold a T, the statement will trigger a panic. To test whether an interface value holds a specific type, a type assertion can return two values: the underlying value and a boolean value that reports whether the assertion succeeded.

t, ok := i.(T)

if t, ok := i.(T); ok {
...
}

• Method names written from upper-case letter are exported form module
• to write internal methods (like static function in c) start function name from lower case

func main() {
  add := func(x, y int) int {
    return x + y
  }
  fmt.Println(add(1,1))
}

func makeEvenGenerator() func() uint {
  i := uint(0)
  return func() (ret uint) {
    ret = i
    i += 2
    return
  }
}

    moreBytes := []byte{1,2,3,4}
    bytes := []byte{2}
    bytes = append(bytes, 4)
    bytes = append(bytes, moreBytes...)