OpenWest 2014/Go

Ken Thompson - Unix

Google

Gopher - GopherCon 2014

Utah Go Users Group - http://www.utahgophers.com

• Tues. May 13 @ 6:30pm

The Go Programming Language Specification - The Go Programming Language - http://golang.org/ref/spec

Justifications:

• C++ too complex
• compilation too slow
• programming to difficult
• easy over safety and efficiency

Issues:

• Name "Go" is ungoogable / hastagable (use golang) *** MOST ANNOYING ***

Companies who use Go:

• PayPal
• Github
• MongoDB
• Canonical
• Mozilla
• Stack Overflow
• Puppet Labs

Twitter: #golang

Prediction: Will become dominant language for LaaS and PaaS in 24 months

Go is...

• Compiled
• Strongly typed
• Statically typed
• Garbage collected
• Similar to C syntax
• Capable of statically verified duck typing (via interfaces)
• Open Source

Hello World:

package main

import "fmt"

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

Note: Semi colons are optional.

Variables:

pakcage main

import "fmt"

func main() {
    var i, j int = 1, 2
    k := 3
    c, python, java := true, false, "no!"
    fmt.Println(i, j, k, c, python, java)
}

When variables are first initialized, they are always set to their "zero" value. There isn't a null value?

Comments:

// comments use C's syntax
/* multi line comment */

Functions:

package main

import "fmt"

func add(x int, y int) int {
    return x + y
}

func main() {
    fmt.Println(...??
}

Types:

• bool
• string
• int, int32, ...
• uint, uint8, ...
• byte
• rune alias for int32
• float32
• complex64

Type conversions - no implicit conversions (have to manually cast)

Looping - Go only has 'for'

for i := 0; i < MAX ; i++ { ... }

While:

for ; sum < 1000;  { sum += sum }
for sum < 1000 { sum += sum }

If/Else

if x < 0 { ... }
else if x > 0 { ... }
else { ... }

Don't fear Go pointers

type Coordinate struct {
  X int
  Y int
  Z int
  name string
}

func GCP() *Coordinate {
  return &Coordinate{1, 2, 3, "foo"}
}

func main() {
 var cp *Coorindate = getCCP()
  fmt.Println(cp)
 fmt.Printf("%T\n", cp)
 ...
}

Slices

Range

var pow = []int{1, 2, 3}
func main() {
  for i, v := range pow {
    fmt.Printf("%d: %d\n", i, v)
   }
}

for _, v := range pow { ... }
// underscore is special

Maps

Access is marked public/private by the first letter of the member. Public is capital. Private is lowercase.

No assertions?

Structs in Go - instead of classes in Object Oriented Programming

type House struct { }
func (h House) GetHouseName() string { } //method defined outside of struct, but works on House

Interfaces are super important in Go.

type noiser interface{
   GetNoise() string
}
type Cow struct{}   // empty structs
type Fox struct{}
func (f Fox) GetNoise() string { ... }