lua fibonacci with closure.

fibonacci.lua

local function my_ipairs(t)
   local i = 1
   return function()
      local v = t[i]
      if v then
         local ii = i
         i = i + 1
         return ii, v
      else
         return nil
      end
   end
end

local function my_pairs(t)
   local k, v
   return function()
      k, v = next(t, k)
      if v then
         return k, v
      else
         return nil
      end
   end
end

local t = {1, 2, 3, 4}

local kv = {a = 1, b = 2, c = 3, d = 4}

for k, v in my_ipairs(t) do
   print(k, v)
end
for k, v in my_pairs(t) do
   print(k, v)
end

for k, v in my_ipairs(kv) do
   print(k, v)
end

for k, v in my_pairs(kv) do
   print(k, v)
end

local function my_fibonacci(times)
   local i = 1
   local next_i = 1
   local n = 0
   return function()
      local _i, _next_i = i, next_i
      i = _next_i + _i
      next_i = i + next_i
      n = n + 1
      if n <= times then
         return _i, _next_i
      else
         return nil
      end
   end
end

for i, ii in my_fibonacci(20) do
   print(i, ii)
end