fixpoint.lua

--  print((function(f) return (function(x) return f(function(...) return x(x)(...) end) end)(function(x) return f(function(...) return x(x)(...) end) end) end)(function(f) return function(n) if n==0 then return 1 else return n*f(n-1) end end end)(10))

local function fix(f)
        return (function(x)
                return f(function(...)
                                return x(x)(...)
                end)
        end)(function(x)
                        return f(function(...)
                                        return x(x)(...)
                        end)
        end)
end

local function fact(self,n) if n==0 then return 1 else return n*self(n-1) end end

print(fix(function(f) return function(n) return fact(f, n) end end)(5))