A sideways introduction to programming in go via the medium of for loops

1. going loopy
adventures in iteration with google go
!
!
@feyeleanor
Going Loopy
!1
http://slideshare.net/feyeleanor/

2. the conditional loop
Going Loopy
!2
http://slides.games-with-brains.net/

3. package main
import "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
for i := 0; i < len(s); i++ {
fmt.Printf("%v: %vn", i, s[i])
}
}
Going Loopy
!3
http://slides.games-with-brains.net/

4. package main
import "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
for i := 0; i < len(s); i++ {
fmt.Printf("%v: %vn", i, s[i])
}
}
!
!
0:
1:
2:
3:
4:
Going Loopy
0
2
4
6
8
!4
http://slides.games-with-brains.net/

5. package main
import "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
for i := 0; i < len(s); i++ {
fmt.Printf("%v: %vn", i, s[i])
}
}
Going Loopy
!5
http://slides.games-with-brains.net/

6. package main
import "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
for i := 0; i < len(s); i++ {
fmt.Printf("%v: %vn", i, s[i])
}
}
Going Loopy
!6
http://slides.games-with-brains.net/

7. package main
import "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
for i := 0; i < len(s); i++ {
fmt.Printf("%v: %vn", i, s[i])
}
}
Going Loopy
!7
http://slides.games-with-brains.net/

8. package main
import . "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
for i := 0; i < len(s); i++ {
Printf("%v: %vn", i, s[i])
}
}
Going Loopy
!8
http://slides.games-with-brains.net/

9. package main
import . "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
for i := 0; i < len(s); i++ {
Printf("%v: %vn", i, s[i])
}
}
Going Loopy
!9
http://slides.games-with-brains.net/

10. package main
import . "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
for i := 0; i < len(s); i++ {
Printf("%v: %vn", i, s[i])
}
}
Going Loopy
!10
http://slides.games-with-brains.net/

11. package main
import . "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
for i := 0; i < len(s); i++ {
Printf("%v: %vn", i, s[i])
}
}
Going Loopy
!11
http://slides.games-with-brains.net/

12. package main
import . "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
for i := 0; i < len(s); i++ {
Printf("%v: %vn", i, s[i])
}
}
Going Loopy
!12
http://slides.games-with-brains.net/

13. package main
import . "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
for i := 0; i < len(s); i++ {
Printf("%v: %vn", i, s[i])
}
}
Going Loopy
!13
http://slides.games-with-brains.net/

14. package main
import . "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
for i := 0; i < len(s); i++ {
Printf("%v: %vn", i, s[i])
}
}
Going Loopy
!14
http://slides.games-with-brains.net/

15. package main
import . "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
for i := 0; i < len(s); i++ {
Printf("%v: %vn", i, s[i])
}
}
Going Loopy
!15
http://slides.games-with-brains.net/

16. package main
import . "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
for i := 0; i < len(s); i++ {
Printf("%v: %vn", i, s[i])
}
}
Going Loopy
!16
http://slides.games-with-brains.net/

17. package main
import . "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
for i := 0; i < len(s); i++ {
Printf("%v: %vn", i, s[i])
}
}
Going Loopy
!17
http://slides.games-with-brains.net/

18. package main
import . "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
for i := 0; i < len(s); i++ {
Printf("%v: %vn", i, s[i])
}
}
Going Loopy
!18
http://slides.games-with-brains.net/

19. package main
import . "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
for i := 0; i < len(s); i++ {
Printf("%v: %vn", i, s[i])
}
}
Going Loopy
!19
http://slides.games-with-brains.net/

20. package main
import . "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
for i := 0; i < len(s); i++ {
Printf("%v: %vn", i, s[i])
}
}
Going Loopy
!20
http://slides.games-with-brains.net/

21. package main
import . "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
for i := 0; i < len(s); i++ {
Printf("%v: %vn", i, s[i])
}
}
Going Loopy
!21
http://slides.games-with-brains.net/

22. package main
import . "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
for i := 0; i < len(s); i++ {
Printf("%v: %vn", i, s[i])
}
}
Going Loopy
!22
http://slides.games-with-brains.net/

23. package main
import . "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
for i := 0; i < len(s); i++ {
Printf("%v: %vn", i, s[i])
}
}
Going Loopy
!23
http://slides.games-with-brains.net/

24. the infinite loop
Going Loopy
!24
http://slides.games-with-brains.net/

25. package main
import . "fmt"
!
func main() {
defer func() {
recover()
}()
s := []int{0, 2, 4, 6, 8}
i := 0
for {
Printf("%v: %vn", i, s[i])
i++
}
}
Going Loopy
!25
http://slides.games-with-brains.net/

26. package main
import . "fmt"
!
func main() {
defer func() {
recover()
}()
s := []int{0, 2, 4, 6, 8}
i := 0
for {
Printf("%v: %vn", i, s[i])
i++
}
}
Going Loopy
!26
http://slides.games-with-brains.net/

27. package main
import . "fmt"
!
func main() {
defer func() {
recover()
}()
s := []int{0, 2, 4, 6, 8}
i := 0
for {
Printf("%v: %vn", i, s[i])
i++
}
}
Going Loopy
!27
http://slides.games-with-brains.net/

28. package main
import . "fmt"
!
func main() {
defer func() {
recover()
}()
s := []int{0, 2, 4, 6, 8}
i := 0
for {
Printf("%v: %vn", i, s[i])
i++
}
}
Going Loopy
!28
http://slides.games-with-brains.net/

29. package main
import . "fmt"
!
func main() {
defer func() {
recover()
}()
s := []int{0, 2, 4, 6, 8}
i := 0
for {
Printf("%v: %vn", i, s[i])
i++
}
}
Going Loopy
!29
http://slides.games-with-brains.net/

30. package main
import . "fmt"
!
func main() {
defer func() {
recover()
}()
s := []int{0, 2, 4, 6, 8}
i := 0
for {
Printf("%v: %vn", i, s[i])
i++
}
}
Going Loopy
!30
http://slides.games-with-brains.net/

31. package main
import . "fmt"
!
func main() {
defer func() {
recover()
}()
s := []int{0, 2, 4, 6, 8}
i := 0
for i := 0; ; i++ {
Printf("%v: %vn", i, s[i])
i++
}
}
Going Loopy
!31
http://slides.games-with-brains.net/

32. the range
Going Loopy
!32
http://slides.games-with-brains.net/

33. package main
import . "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
for i, v := range s {
Printf("%v: %vn", i, v)
}
}
Going Loopy
!33
http://slides.games-with-brains.net/

34. package main
import . "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
for i, v := range s {
Printf("%v: %vn", i, v)
}
}
Going Loopy
!34
http://slides.games-with-brains.net/

35. package main
import . "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
for i, v := range s {
Printf("%v: %vn", i, v)
}
}
Going Loopy
!35
http://slides.games-with-brains.net/

36. package main
import . "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
for i, v := range s {
Printf("%v: %vn", i, v)
}
}
Going Loopy
!36
http://slides.games-with-brains.net/

37. package main
import . "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
for i, v := range s {
Printf("%v: %vn", i, v)
}
}
Going Loopy
!37
http://slides.games-with-brains.net/

38. package main
import . "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
for i, v := range s {
Printf("%v: %vn", i, v)
}
}
Going Loopy
!38
http://slides.games-with-brains.net/

39. a functional interlude
Going Loopy
!39
http://slides.games-with-brains.net/

40. package main
import . "fmt"
!
func main() {
print_slice([]int{0, 2, 4, 6, 8})
}
!
func print_slice(s []int) {
for i, v := range s {
Printf("%v: %vn", i, v)
}
}
Going Loopy
!40
http://slides.games-with-brains.net/

41. package main
import . "fmt"
!
func main() {
print_slice([]int{0, 2, 4, 6, 8})
}
!
func print_slice(s []int) {
for i, v := range s {
Printf("%v: %vn", i, v)
}
}
Going Loopy
!41
http://slides.games-with-brains.net/

42. package main
import . "fmt"
!
func main() {
print_slice([]int{0, 2, 4, 6, 8})
}
!
func print_slice(s []int) {
for i, v := range s {
Printf("%v: %vn", i, v)
}
}
Going Loopy
!42
http://slides.games-with-brains.net/

43. package main
import . "fmt"
!
func main() {
print_slice([]int{0, 2, 4, 6, 8})
}
!
func print_slice(s []int) {
for i, v := range s {
Printf("%v: %vn", i, v)
}
}
Going Loopy
!43
http://slides.games-with-brains.net/

44. package main
import . "fmt"
!
func main() {
print_slice(0, 2, 4, 6, 8)
}
!
func print_slice(s ...int) {
for i, v := range s {
Printf("%v: %vn", i, v)
}
}
Going Loopy
!44
http://slides.games-with-brains.net/

45. package main
import . "fmt"
!
func main() {
print_slice(0, 2, 4, 6, 8)
}
!
func print_slice(s ...int) {
for i, v := range s {
Printf("%v: %vn", i, v)
}
}
Going Loopy
!45
http://slides.games-with-brains.net/

46. package main
import . "fmt"
!
func main() {
print_slice(0, 2, 4, 6, 8)
}
!
func print_slice(s ...int) {
for i, v := range s {
Printf("%v: %vn", i, v)
}
}
Going Loopy
!46
http://slides.games-with-brains.net/

47. asserting type
Going Loopy
!47
http://slides.games-with-brains.net/

48. package main
import . "fmt"
!
func main() {
print_slice([]int{0, 2, 4, 6, 8})
}
!
func print_slice(s interface{}) {
for i, v := range s.([]int) {
Printf("%v: %vn", i, v)
}
}
Going Loopy
!48
http://slides.games-with-brains.net/

49. package main
import . "fmt"
!
func main() {
print_slice([]int{0, 2, 4, 6, 8})
}
!
func print_slice(s interface{}) {
for i, v := range s.([]int) {
Printf("%v: %vn", i, v)
}
}
Going Loopy
!49
http://slides.games-with-brains.net/

50. package main
import . "fmt"
!
func main() {
print_slice([]int{0, 2, 4, 6, 8})
}
!
func print_slice(s interface{}) {
for i, v := range s.([]int) {
Printf("%v: %vn", i, v)
}
}
Going Loopy
!50
http://slides.games-with-brains.net/

51. package main
import . "fmt"
!
func main() {
print_slice([]int{0, 2, 4, 6, 8})
}
!
func print_slice(s interface{}) {
if s, ok := s.([]int); ok {
for i, v := range s {
Printf("%v: %vn", i, v)
}
}
}
Going Loopy
!51
http://slides.games-with-brains.net/

52. package main
import . "fmt"
!
func main() {
print_slice([]int{0, 2, 4, 6, 8})
}
!
func print_slice(s interface{}) {
if s, ok := s.([]int); ok {
for i, v := range s {
Printf("%v: %vn", i, v)
}
}
}
Going Loopy
!52
http://slides.games-with-brains.net/

53. package main
import . "fmt"
!
func main() {
print_slice([]int{0, 2, 4, 6, 8})
}
!
func print_slice(s interface{}) {
if s, ok := s.([]int); ok {
for i, v := range s {
Printf("%v: %vn", i, v)
}
}
}
Going Loopy
!53
http://slides.games-with-brains.net/

54. package main
import . "fmt"
!
func main() {
print_slice([]int{0, 2, 4, 6, 8})
}
!
func print_slice(s interface{}) {
if s, ok := s.([]int); ok {
for i, v := range s {
Printf("%v: %vn", i, v)
}
}
}
Going Loopy
!54
http://slides.games-with-brains.net/

55. package main
import . "fmt"
!
func main() {
print_slice([]int{0, 2, 4, 6, 8})
}
!
func print_slice(s interface{}) {
if s, ok := s.([]int); ok {
for i, v := range s {
Printf("%v: %vn", i, v)
}
}
}
Going Loopy
!55
http://slides.games-with-brains.net/

56. package main
import . "fmt"
!
func main() {
print_slice([]int{0, 2, 4, 6, 8})
}
!
func print_slice(s interface{}) {
if s, ok := s.([]int); ok {
for i, v := range s {
Printf("%v: %vn", i, v)
}
}
}
Going Loopy
!56
http://slides.games-with-brains.net/

57. package main
import . "fmt"
!
func main() {
print_slice([]int{0, 2, 4, 6, 8})
}
!
func print_slice(s interface{}) {
switch s := s.(type) {
case []int:
for i, v := range s {
Printf("%v: %vn", i, v)
}
}
}
Going Loopy
!57
http://slides.games-with-brains.net/

58. package main
import . "fmt"
!
func main() {
print_slice([]int{0, 2, 4, 6, 8})
}
!
func print_slice(s interface{}) {
switch s := s.(type) {
case []int:
for i, v := range s {
Printf("%v: %vn", i, v)
}
}
}
Going Loopy
!58
http://slides.games-with-brains.net/

59. package main
import . "fmt"
!
func main() {
print_slice([]int{0, 2, 4, 6, 8})
}
!
func print_slice(s interface{}) {
switch s := s.(type) {
case []int:
for i, v := range s {
Printf("%v: %vn", i, v)
}
}
}
Going Loopy
!59
http://slides.games-with-brains.net/

60. package main
import . "fmt"
!
func main() {
print_slice([]int{0, 2, 4, 6, 8})
}
!
func print_slice(s interface{}) {
switch s := s.(type) {
case []int:
for i, v := range s {
Printf("%v: %vn", i, v)
}
}
}
Going Loopy
!60
http://slides.games-with-brains.net/

61. package main
import . "fmt"
!
func main() {
print_slice([]int{0, 2, 4, 6, 8})
}
!
func print_slice(s interface{}) {
switch s := s.(type) {
case []int:
for i, v := range s {
Printf("%v: %vn", i, v)
}
}
}
Going Loopy
!61
http://slides.games-with-brains.net/

62. package main
import . "fmt"
!
func main() {
print_slice([]int{0, 2, 4, 6, 8})
}
!
func print_slice(s interface{}) {
switch s := s.(type) {
case []int:
for i, v := range s {
Printf("%v: %vn", i, v)
}
}
}
Going Loopy
!62
http://slides.games-with-brains.net/

63. closures
Going Loopy
!63
http://slides.games-with-brains.net/

64. package main
import . "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
print_slice(func(i int) int { return s[i] })
}
!
func print_slice(s interface{}) {
switch s := s.(type) {
case func(int) int:
for i := 0; i < 5; i++ {
Printf("%v: %vn", i, s(i))
}
}
}
Going Loopy
!64
http://slides.games-with-brains.net/

65. package main
import . "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
print_slice(func(i int) int { return s[i] })
}
!
func print_slice(s interface{}) {
switch s := s.(type) {
case func(int) int:
for i := 0; i < 5; i++ {
Printf("%v: %vn", i, s(i))
}
}
}
Going Loopy
!65
http://slides.games-with-brains.net/

66. package main
import . "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
print_slice(func(i int) int { return s[i] })
}
!
func print_slice(s interface{}) {
switch s := s.(type) {
case func(int) int:
for i := 0; i < 5; i++ {
Printf("%v: %vn", i, s(i))
}
}
}
Going Loopy
!66
http://slides.games-with-brains.net/

67. package main
import . "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
print_slice(func(i int) int { return s[i] })
}
!
func print_slice(s interface{}) {
switch s := s.(type) {
case func(int) int:
for i := 0; i < 5; i++ {
Printf("%v: %vn", i, s(i))
}
}
}
Going Loopy
!67
http://slides.games-with-brains.net/

68. package main
import . "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
print_slice(func(i int) int { return s[i] })
}
!
func print_slice(s interface{}) {
switch s := s.(type) {
case func(int) int:
for i := 0; i < 5; i++ {
Printf("%v: %vn", i, s(i))
}
}
}
Going Loopy
!68
http://slides.games-with-brains.net/

69. package main
import . "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
print_slice(func(i int) int { return s[i] })
}
!
func print_slice(s interface{}) {
switch s := s.(type) {
case func(int) int:
for i := 0; i < 5; i++ {
Printf("%v: %vn", i, s(i))
}
}
}
Going Loopy
!69
http://slides.games-with-brains.net/

70. package main
import . "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
print_slice(func(i int) int { return s[i] })
}
!
func print_slice(s interface{}) {
switch s := s.(type) {
case func(int) int:
for i := 0; i < 5; i++ {
Printf("%v: %vn", i, s(i))
}
}
}
Going Loopy
!70
http://slides.games-with-brains.net/

71. package main
import . "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
print_slice(func(i int) int { return s[i] })
}
!
func print_slice(s interface{}) {
switch s := s.(type) {
case func(int) int:
for i := 0; i < 5; i++ {
Printf("%v: %vn", i, s(i))
}
}
}
Going Loopy
!71
http://slides.games-with-brains.net/

72. package main
import . "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
print_slice(func(i int) int { return s[i] })
}
!
func print_slice(s interface{}) {
switch s := s.(type) {
case func(int) int:
for i := 0; i < 5; i++ {
Printf("%v: %vn", i, s(i))
}
}
}
Going Loopy
!72
http://slides.games-with-brains.net/

73. package main
import . "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
print_slice(func(i int) int { return s[i] })
}
!
func print_slice(s interface{}) {
switch s := s.(type) {
case func(int) int:
for i := 0; i < 5; i++ {
Printf("%v: %vn", i, s(i))
}
}
}
Going Loopy
!73
http://slides.games-with-brains.net/

74. channels
Going Loopy
!74
http://slides.games-with-brains.net/

75. package main
import . "fmt"
!
func main() {
c := make(chan int)
go func() {
for _, v := range []int{0, 2, 4, 6, 8} {
c <- v
}
close(c)
}()
Printf("elements: %vn", print_channel(c))
}
!
func print_channel(c chan int) (i int) {
for v := range c {
Printf("%v: %vn", i, v)
i++
}
return
}
Going Loopy
!75
http://slides.games-with-brains.net/

76. package main
import . "fmt"
!
func main() {
c := make(chan int)
go func() {
for _, v := range []int{0, 2, 4, 6, 8} {
c <- v
}
close(c)
}()
Printf("elements: %vn", print_channel(c))
}
!
func print_channel(c chan int) (i int) {
for v := range c {
Printf("%v: %vn", i, v)
i++
}
return
}
Going Loopy
!76
http://slides.games-with-brains.net/

77. package main
import . "fmt"
!
func main() {
c := make(chan int, 16)
go func() {
for _, v := range []int{0, 2, 4, 6, 8} {
c <- v
}
close(c)
}()
Printf("elements: %vn", print_channel(c))
}
!
func print_channel(c chan int) (i int) {
for v := range c {
Printf("%v: %vn", i, v)
i++
}
return
}
Going Loopy
!77
http://slides.games-with-brains.net/

78. package main
import . "fmt"
!
func main() {
c := make(chan int)
go func() {
for _, v := range []int{0, 2, 4, 6, 8} {
c <- v
}
close(c)
}()
Printf("elements: %vn", print_channel(c))
}
!
func print_channel(c chan int) (i int) {
for v := range c {
Printf("%v: %vn", i, v)
i++
}
return
}
Going Loopy
!78
http://slides.games-with-brains.net/

79. package main
import . "fmt"
!
func main() {
c := make(chan int)
go func() {
for _, v := range []int{0, 2, 4, 6, 8} {
c <- v
}
close(c)
}()
Printf("elements: %vn", print_channel(c))
}
!
func print_channel(c chan int) (i int) {
for v := range c {
Printf("%v: %vn", i, v)
i++
}
return
}
Going Loopy
!79
http://slides.games-with-brains.net/

80. package main
import . "fmt"
!
func main() {
c := make(chan int)
go func() {
for _, v := range []int{0, 2, 4, 6, 8} {
c <- v
}
close(c)
}()
Printf("elements: %vn", print_channel(c))
}
!
func print_channel(c chan int) (i int) {
for v := range c {
Printf("%v: %vn", i, v)
i++
}
return
}
Going Loopy
!80
http://slides.games-with-brains.net/

81. package main
import . "fmt"
!
func main() {
c := make(chan int)
go func() {
for _, v := range []int{0, 2, 4, 6, 8} {
c <- v
}
close(c)
}()
Printf("elements: %vn", print_channel(c))
}
!
func print_channel(c chan int) (i int) {
for v := range c {
Printf("%v: %vn", i, v)
i++
}
return
}
Going Loopy
!81
http://slides.games-with-brains.net/

82. package main
import . "fmt"
!
func main() {
c := make(chan int)
go func() {
for _, v := range []int{0, 2, 4, 6, 8} {
c <- v
}
close(c)
}()
Printf("elements: %vn", print_channel(c))
}
!
func print_channel(c chan int) (i int) {
for v := range c {
Printf("%v: %vn", i, v)
i++
}
return
}
Going Loopy
!82
http://slides.games-with-brains.net/

83. package main
import . "fmt"
!
func main() {
c := make(chan int)
go func() {
for _, v := range []int{0, 2, 4, 6, 8} {
c <- v
}
close(c)
}()
Printf("elements: %vn", print_channel(c))
}
!
func print_channel(c chan int) (i int) {
for v := range c {
Printf("%v: %vn", i, v)
i++
}
return
}
Going Loopy
!83
http://slides.games-with-brains.net/

84. package main
import . "fmt"
!
func main() {
c := make(chan int)
go func() {
for _, v := range []int{0, 2, 4, 6, 8} {
c <- v
}
close(c)
}()
Printf("elements: %vn", print_channel(c))
}
!
func print_channel(c chan int) (i int) {
for v := range c {
Printf("%v: %vn", i, v)
i++
}
return
}
Going Loopy
!84
http://slides.games-with-brains.net/

85. upon reflection
Going Loopy
!85
http://slides.games-with-brains.net/

86. package main
import . "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
print_values(s)
print_values(func(i int) int { return s[i] * 2 })
}
!
func print_values(s interface{}) {
switch s := s.(type) {
case func(int) int:
for i := 0; i < 5; i++ {
Printf("%v: %vn", i, s(i))
}
case []int:
for i, v := range s {
Printf("%v: %vn", i, v)
}
}
}
Going Loopy
!86
http://slides.games-with-brains.net/

87. package main
import . "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
print_values(s)
print_values(func(i int) int { return s[i] * 2 })
}
!
func print_values(s interface{}) {
switch s := s.(type) {
case func(int) int:
for i := 0; i < 5; i++ {
Printf("%v: %vn", i, s(i))
}
case []int:
for i, v := range s {
Printf("%v: %vn", i, v)
}
}
}
Going Loopy
!87
http://slides.games-with-brains.net/

88. package main
import . "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
print_values(s)
print_values(func(i int) int { return s[i] * 2 })
}
!
func print_values(s interface{}) {
switch s := s.(type) {
case func(int) int:
for i := 0; i < 5; i++ {
Printf("%v: %vn", i, s(i))
}
case []int:
for i, v := range s {
Printf("%v: %vn", i, v)
}
}
}
Going Loopy
!88
http://slides.games-with-brains.net/

89. package main
import . "fmt"
!
func main() {
s := []int{0, 2, 4, 6, 8}
print_values(s)
print_values(func(i int) int { return s[i] * 2 })
}
!
func print_values(s interface{}) {
switch s := s.(type) {
case func(int) int:
for i := 0; i < 5; i++ {
Printf("%v: %vn", i, s(i))
}
case []int:
for i, v := range s {
Printf("%v: %vn", i, v)
}
}
}
Going Loopy
!89
http://slides.games-with-brains.net/

90. package main
import . "fmt"
import . "reflect"
!
func main() {
s := []int{0, 2, 4, 6, 8}
print_values(s)
print_values(func(i int) int { return s[i] })
}
!
func print_values(s interface{}) {
switch s := ValueOf(s); s.Kind() {
case Func:
p := []Value{ ValueOf(i) }
for i := 0; i < 5; i++ {
Printf("%v: %vn", i, s.Call(p)[0].Interface{})
}
case Slice:
for i := 0; i < s.Len(); i++ {
Printf("%v: %vn", i, s.Index(i))
}
}
}
Going Loopy
!90
http://slides.games-with-brains.net/

91. package main
import . "fmt"
import . "reflect"
!
func main() {
s := []int{0, 2, 4, 6, 8}
print_values(s)
print_values(func(i int) int { return s[i] })
}
!
func print_values(s interface{}) {
switch s := ValueOf(s); s.Kind() {
case Func:
p := []Value{ ValueOf(i) }
for i := 0; i < 5; i++ {
Printf("%v: %vn", i, s.Call(p)[0].Interface{})
}
case Slice:
for i := 0; i < s.Len(); i++ {
Printf("%v: %vn", i, s.Index(i))
}
}
}
Going Loopy
!91
http://slides.games-with-brains.net/

92. package main
import . "fmt"
import . "reflect"
!
func main() {
s := []int{0, 2, 4, 6, 8}
print_values(s)
print_values(func(i int) int { return s[i] })
}
!
func print_values(s interface{}) {
switch s := ValueOf(s); s.Kind() {
case Func:
p := []Value{ ValueOf(i) }
for i := 0; i < 5; i++ {
Printf("%v: %vn", i, s.Call(p)[0].Interface())
}
case Slice:
for i := 0; i < s.Len(); i++ {
Printf("%v: %vn", i, s.Index(i).Interface())
}
}
}
Going Loopy
!92
http://slides.games-with-brains.net/

93. package main
import . "fmt"
import . "reflect"
!
func main() {
s := []int{0, 2, 4, 6, 8}
print_values(s)
print_values(func(i int) int { return s[i] })
}
!
func print_values(s interface{}) {
switch s := ValueOf(s); s.Kind() {
case Func:
p := []Value{ ValueOf(i) }
for i := 0; i < 5; i++ {
Printf("%v: %vn", i, s.Call(p)[0].Interface())
}
case Slice:
for i := 0; i < s.Len(); i++ {
Printf("%v: %vn", i, s.Index(i).Interface())
}
}
}
Going Loopy
!93
http://slides.games-with-brains.net/

94. package main
import . "fmt"
import . "reflect"
!
func main() {
s := []int{0, 2, 4, 6, 8}
print_values(s)
print_values(func(i int) int { return s[i] })
}
!
func print_values(s interface{}) {
switch s := ValueOf(s); s.Kind() {
case Func:
p := []Value{ ValueOf(i) }
for i := 0; i < 5; i++ {
Printf("%v: %vn", i, s.Call(p)[0].Interface())
}
case Slice:
for i := 0; i < s.Len(); i++ {
Printf("%v: %vn", i, s.Index(i).Interface())
}
}
}
Going Loopy
!94
http://slides.games-with-brains.net/

95. package main
import . "fmt"
import . "reflect"
!
func main() {
s := []int{0, 2, 4, 6, 8}
print_values(s)
print_values(func(i int) int { return s[i] })
}
!
func print_values(s interface{}) {
switch s := ValueOf(s); s.Kind() {
case Func:
p := []Value{ ValueOf(i) }
for i := 0; i < 5; i++ {
Printf("%v: %vn", i, s.Call(p)[0].Interface())
}
case Slice:
for i := 0; i < s.Len(); i++ {
Printf("%v: %vn", i, s.Index(i).Interface())
}
}
}
Going Loopy
!95
http://slides.games-with-brains.net/

96. package main
import . "fmt"
import . "reflect"
!
func main() {
s := []int{0, 2, 4, 6, 8}
print_values(s)
print_values(func(i int) int { return s[i] })
}
!
func print_values(s interface{}) {
switch s := ValueOf(s); s.Kind() {
case Func:
p := []Value{ ValueOf(i) }
for i := 0; i < 5; i++ {
Printf("%v: %vn", i, s.Call(p)[0].Interface())
}
case Slice:
for i := 0; i < s.Len(); i++ {
Printf("%v: %vn", i, s.Index(i).Interface())
}
}
}
Going Loopy
!96
http://slides.games-with-brains.net/

97. package main
import . "fmt"
import . "reflect"
!
func main() {
s := []int{0, 2, 4, 6, 8}
print_values(s)
print_values(func(i int) int { return s[i] })
}
!
func print_values(s interface{}) {
switch s := ValueOf(s); s.Kind() {
case Func:
p := []Value{ ValueOf(i) }
for i := 0; i < 5; i++ {
Printf("%v: %vn", i, s.Call(p)[0].Interface())
}
case Slice:
for i := 0; i < s.Len(); i++ {
Printf("%v: %vn", i, s.Index(i).Interface())
}
}
}
Going Loopy
!97
http://slides.games-with-brains.net/

98. package main
import . "fmt"
import . "reflect"
!
func main() {
s := []int{0, 2, 4, 6, 8}
print_values(s)
print_values(func(i int) int { return s[i] })
}
!
func print_values(s interface{}) {
switch s := ValueOf(s); s.Kind() {
case Func:
p := []Value{ ValueOf(i) }
for i := 0; i < 5; i++ {
Printf("%v: %vn", i, s.Call(p)[0].Interface())
}
case Slice:
for i := 0; i < s.Len(); i++ {
Printf("%v: %vn", i, s.Index(i).Interface())
}
}
}
Going Loopy
!98
http://slides.games-with-brains.net/

99. package main
import . "fmt"
import . "reflect"
!
func main() {
s := []int{0, 2, 4, 6, 8}
print_values(s)
print_values(func(i int) int { return s[i] })
}
!
func print_values(s interface{}) {
switch s := ValueOf(s); s.Kind() {
case Func:
p := []Value{ ValueOf(i) }
for i := 0; i < 5; i++ {
Printf("%v: %vn", i, s.Call(p)[0].Interface())
}
case Slice:
for i := 0; i < s.Len(); i++ {
Printf("%v: %vn", i, s.Index(i).Interface())
}
}
}
Going Loopy
!99
http://slides.games-with-brains.net/

100. package main
import . "fmt"
import . "reflect"
!
func main() {
s := []int{0, 2, 4, 6, 8}
print_values(s)
print_values(func(i int) int { return s[i] })
}
!
func print_values(s interface{}) {
switch s := ValueOf(s); s.Kind() {
case Func:
p := []Value{ ValueOf(i) }
for i := 0; i < 5; i++ {
Printf("%v: %vn", i, s.Call(p)[0].Interface())
}
case Slice:
for i := 0; i < s.Len(); i++ {
Printf("%v: %vn", i, s.Index(i).Interface())
}
}
}
Going Loopy
!100
http://slides.games-with-brains.net/

101. package main
import . "fmt"
import . "reflect"
!
func main() {
s := []int{0, 2, 4, 6, 8}
print_values(s)
print_values(func(i int) int { return s[i] })
}
!
func print_values(s interface{}) {
switch s := ValueOf(s); s.Kind() {
case Func:
p := []Value{ ValueOf(i) }
for i := 0; i < 5; i++ {
Printf("%v: %vn", i, s.Call(p)[0].Interface())
}
case Slice:
for i := 0; i < s.Len(); i++ {
Printf("%v: %vn", i, s.Index(i).Interface())
}
}
}
Going Loopy
!101
http://slides.games-with-brains.net/

102. package main
import . "fmt"
import . "reflect"
!
func main() {
s := []int{0, 2, 4, 6, 8}
print_values(s)
print_values(func(i int) int { return s[i] })
}
!
func print_values(s interface{}) {
switch s := ValueOf(s); s.Kind() {
case Func:
p := []Value{ ValueOf(i) }
for i := 0; i < 5; i++ {
Printf("%v: %vn", i, s.Call(p)[0].Interface())
}
case Slice:
for i := 0; i < s.Len(); i++ {
Printf("%v: %vn", i, s.Index(i).Interface())
}
}
}
Going Loopy
!102
http://slides.games-with-brains.net/

103. user-defined type
Going Loopy
!103
http://slides.games-with-brains.net/

104. package main
import . "fmt"
!
type Iterable interface {
Each(func(interface{}))
}
!
type IterableSlice []int
func (i IterableSlice) Each(f func(interface{})) {
for _, v := range i {
f(v)
}
}
!
func main() {
s := IterableSlice{ 0, 2, 4, 6, 8 }
i := 0
s.Each(func(v interface{}) {
Printf("%v: %vn", i, v)
i++
})
}
Going Loopy
!104
http://slides.games-with-brains.net/

105. package main
import . "fmt"
!
type Iterable interface {
Each(func(interface{}))
}
!
type IterableSlice []int
func (i IterableSlice) Each(f func(interface{})) {
for _, v := range i {
f(v)
}
}
!
func main() {
s := IterableSlice{ 0, 2, 4, 6, 8 }
i := 0
s.Each(func(v interface{}) {
Printf("%v: %vn", i, v)
i++
})
}
Going Loopy
!105
http://slides.games-with-brains.net/

106. package main
import . "fmt"
!
type Iterable interface {
Each(func(interface{}))
}
!
type IterableSlice []int
func (i IterableSlice) Each(f func(interface{})) {
for _, v := range i {
f(v)
}
}
!
func main() {
s := IterableSlice{ 0, 2, 4, 6, 8 }
i := 0
s.Each(func(v interface{}) {
Printf("%v: %vn", i, v)
i++
})
}
Going Loopy
!106
http://slides.games-with-brains.net/

107. package main
import . "fmt"
!
type Iterable interface {
Each(func(interface{}))
}
!
type IterableSlice []int
func (i IterableSlice) Each(f func(interface{})) {
for _, v := range i {
f(v)
}
}
!
func main() {
s := IterableSlice{ 0, 2, 4, 6, 8 }
i := 0
s.Each(func(v interface{}) {
Printf("%v: %vn", i, v)
i++
})
}
Going Loopy
!107
http://slides.games-with-brains.net/

108. package main
import . "fmt"
!
type Iterable interface {
Each(func(interface{}))
}
!
type IterableSlice []int
func (i IterableSlice) Each(f func(interface{})) {
for _, v := range i {
f(v)
}
}
!
func main() {
s := IterableSlice{ 0, 2, 4, 6, 8 }
i := 0
s.Each(func(v interface{}) {
Printf("%v: %vn", i, v)
i++
})
}
Going Loopy
!108
http://slides.games-with-brains.net/

109. package main
import . "fmt"
!
type Iterable interface {
Each(func(interface{}))
}
!
type IterableSlice []int
func (i IterableSlice) Each(f func(interface{})) {
for _, v := range i {
f(v)
}
}
!
func main() {
s := IterableSlice{ 0, 2, 4, 6, 8 }
i := 0
s.Each(func(v interface{}) {
Printf("%v: %vn", i, v)
i++
})
}
Going Loopy
!109
http://slides.games-with-brains.net/

110. package main
import . "fmt"
!
type Iterable interface {
Each(func(interface{}))
}
!
type IterableSlice []int
func (i IterableSlice) Each(f func(interface{})) {
for _, v := range i {
f(v)
}
}
!
func main() {
s := IterableSlice{ 0, 2, 4, 6, 8 }
i := 0
s.Each(func(v interface{}) {
Printf("%v: %vn", i, v)
i++
})
}
Going Loopy
!110
http://slides.games-with-brains.net/

111. package main
import . "fmt"
!
type Iterable interface {
Each(func(interface{}))
}
!
type IterableSlice []int
func (i IterableSlice) Each(f func(interface{})) {
for _, v := range i {
f(v)
}
}
!
func main() {
s := IterableSlice{ 0, 2, 4, 6, 8 }
i := 0
s.Each(func(v interface{}) {
Printf("%v: %vn", i, v)
i++
})
}
Going Loopy
!111
http://slides.games-with-brains.net/

112. you now know go
Going Loopy
112
http://slides.games-with-brains.net/

113. #golang
Going Loopy
113
http://slides.games-with-brains.net/

114. http://golang.org/
Going Loopy
114
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