1 require "seqlua_c_example" -- defines function "printcsv"

2

3 function alphabet()

4 local letter = nil

5 return function()

6 if letter == nil then

7 letter = "a"

8 elseif letter == "z" then

9 return nil

10 else

11 letter = string.char(string.byte(letter) + 1)

12 end

13 return letter

14 end

15 end

16

17 t = {"a", "b", "c"}

18

19 printcsv(t)

20 -- prints:

21 -- a,b,c

22

23 printcsv(alphabet())

24 -- prints:

25 -- a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z

26

27 call_proxy = setmetatable({}, {__ipairs = function() return "call", alphabet() end})

28

29 printcsv(call_proxy)

30 -- prints:

31 -- a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z

32

33 random_access_alphabet = setmetatable({}, {

34 __index = function(self, i)

35 if type(i) == "number" and i >= 1 and i <= 26 then

36 return string.char(string.byte("a") + i - 1)

37 end

38 end

39 })

40

41 printcsv(random_access_alphabet)

42 -- prints:

43 -- a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z

44

45 index_proxy = setmetatable({}, {

46 __ipairs = function() return "index", random_access_alphabet end

47 })

48

49 printcsv(index_proxy)

50 -- prints:

51 -- a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z

52

53 raw_proxy = setmetatable({"dummy"}, {

54 __ipairs = function() return "raw", t end

55 })

56

57 printcsv(raw_proxy)

58 -- prints:

59 -- a,b,c

60

61 require "seqlua"

62

63 do

64 local function ipairsaux(s, i)

65 i = i + 1

66 if i <= s.count then

67 return i, s.entry

68 end

69 end

70 custom_proxy = setmetatable({entry = "zebra", count=5}, {

71 __ipairs = function(self)

72 return ipairsaux, self, 0

73 end

74 })

75 end

76

77 printcsv(custom_proxy)

78 -- prints: zebra,zebra,zebra,zebra,zebra

79