オフラインリアルタイムどう書く第三回の参考問題
http://qiita.com/items/ebd8a56b41711ba459f9

…のgroovyでの回答例
https://gist.github.com/3381668

…をLuaに翻訳してみました。

Baseball = 
{
    s = function(self)
        self.strike = self.strike + 1
        if 2 < self.strike then
            self.strike = 0
            self:o()
        end
    end,

    b = function(self)
        self.ball = self.ball + 1
        if 3 < self.ball then
            self:h()
        end
    end,

    o = function(self)
        self.out = self.out + 1
        if 2 < self.out then
            self.strike = 0
            self.ball   = 0
            self.out    = 0
        end
    end,

    f = function(self)
        if self.strike < 2 then
            self:s()
        end
    end,

    h = function(self)
        self.strike = 0
        self.ball   = 0
    end,

    p = function(self)
        self:h()
        self:o()
    end,

    resolve = function(self, it)
        self.strike = 0
        self.ball   = 0
        self.out    = 0
        local result = ""
        for i = 1, #it do
            self[it:sub(i, i)](self)
            result = result .. "," .. self.out .. self.strike .. self.ball
        end
        return result:sub(2)
    end
}

test =
{
    ["sss"] = "010,020,100",
    ["bbbb"] = "001,002,003,000",
    ["ssbbbb"] = "010,020,021,022,023,000",
    ["hsbhfhbh"] = "000,010,011,000,010,000,001,000",
    ["psbpfpbp"] = "100,110,111,200,210,000,001,100",
    ["ppp"] = "100,200,000",
    ["ffffs"] = "010,020,020,020,100",
    ["ssspfffs"] = "010,020,100,200,210,220,220,000",
    ["bbbsfbppp"] = "001,002,003,013,023,000,100,200,000",
    ["sssbbbbsbhsbppp"] = "010,020,100,101,102,103,100,110,111,100,110,111,200,000,100",
    ["ssffpffssp"] = "010,020,020,020,100,110,120,200,210,000"
}

for k, v in pairs(test) do
  local r = Baseball:resolve(k)
  print("source   = " .. k)
  print("expected = " .. v)
  print("actual   = " .. r)
  print(r == v)
  print()
end