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  1. -- Recursive Style
  2. f = function(a, b)
  3.   if a == 0 then
  4.     return b + 1
  5.   elseif b == 0 then
  6.     return f(a - 1, 1)
  7.   else
  8.     return f(a - 1, f(a, b - 1))
  9.   end
  10. end
  11.  
  12. -- Continuation Passing Style
  13. g = function(a, b, c)
  14.   if a == 0 then
  15.     return c(b + 1)
  16.   elseif b == 0 then
  17.     return g(a - 1, 1, c)
  18.   else
  19.     return g(a, b - 1, function(x)
  20.       return g(a - 1, x, c)
  21.     end)
  22.   end
  23. end
  24.  
  25. -- Loop Style
  26. h = function(a, b)
  27.   local s = {}
  28.   while true do
  29.     if a == 0 then
  30.       if #s ~= 0 then
  31.         s[#s](b + 1)
  32.         table.remove(s)
  33.       else
  34.         break
  35.       end
  36.     elseif b == 0 then
  37.       a = a - 1
  38.       b = 1
  39.     else
  40.       b = b - 1
  41.       table.insert(s, (function(a_)
  42.         return function(x)
  43.           a = a_ - 1
  44.           b = x
  45.         end
  46.       end)(a))
  47.     end
  48.   end
  49.   return b + 1
  50. end
  51.  
  52. print(f(3, 3))
  53.  
  54. print(g(3, 3, function(x)
  55.   return x
  56. end))
  57.  
  58. print(h(3, 3))
  59.  
Success #stdin #stdout 0s 2788KB
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https://ideone.com/XsZh4c
language:
Lua (luac 5.3.3)
created:
8 years ago
visibility:
public

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