SummonMobTower0_1

-- #######################################
-- Summon MobTower
--   required Command Computer in ComputerCraft 1.7 or over.
-- version 0.1, License MIT
-- Twitter: @hevohevo

-- #######################################
-- Functions
local function tbl2TagStr(tbl)
  local str = string.gsub(textutils.serializeJSON(tbl),"\"", "")
  return str
end

local function head(array)
  return array[1]
end

local function rest(array)
  return {select(2,unpack(array))}
end

local function _makeOptsTbl(array)
  local tmp_tbl = {}

  if type(array)~="table" or #array==0 then
    return nil
  else
    tmp_tbl=head(array)
    tmp_tbl["Riding"]=_makeOptsTbl(rest(array))
    return tmp_tbl
  end
end

-- 上から順番に
-- tbl = {{id="Slime",Size=1},{id="Slime",Size=1.5},{id="Slime",Size=2}}
function summonMobTower(tbl, x,y,z)
  assert(tbl[1] and tbl[1]["id"], "invalid arguments")
  local top_mob = tbl[1]
  local data_tags = {}
  for k,v in pairs(top_mob) do
    if k ~= "id" then
      data_tags[k]=v
    end
  end
  if #tbl>1 then
    data_tags["Riding"]=_makeOptsTbl(rest(tbl))
  end
  local text = string.format("summon %s %d %d %d %s", top_mob["id"], x,y,z, tbl2TagStr(data_tags))
  print(text)
  commands.exec(text)
end

-- #######################################
-- Main

-- 上から順に配列で指定
-- opts = {{id="Slime",Size=1, CustomName:"hoge"},
--         {id="Slime",Size=1},
--         {id="Villager"}}
-- summonMobTower(opts, x,y,z)

function Test()
  local cx,cy,cz = commands.getBlockPosition()
  local x, y, z = cx, cy+1, cz
  local tower_tbl = {}
  for i=3,0,-0.2 do
    table.insert(tower_tbl, {id="Slime",Size=i})
  end
  summonMobTower(tower_tbl, x,y,z)
end

for i=1,20 do
  Test()
  os.sleep(1)
end