advTable

local function equal(t1, t2, inner)
  local count = 0
  if inner then
    for i,s in next,t1 do
      count = count + 1
      if type(t1[i]) == "table" and
         type(t2[i]) == "table" then
        if not equal(t1[i], t2[i], true) then
          return false
        end
      elseif t1[i] ~= t2[i] then
        return false
      end
    end
  else
    for i,s in next,t1 do
      count = count + 1
      if s ~= t2[i] then
        return false
      end
    end
  end
  for i,s in next,t2 do
    count = count - 1
  end
  return count == 0
end

local function swap(t, a, b)
  local save = t[a]
  t[a] = t[b]
  t[b] = save
end

local function copy(t, inner)
  if type(t) ~= "table" then
    error("table expected, got "..type(t), 2)
  end
  local new = {}
  if inner then
    for i,s in next,t do
      if type(s) == "table" then
        new[i] = copy(s, true)
      else
        new[i] = s
      end
    end
  else
    for i,s in next,t do
      new[i] = s
    end
  end
  return new
end

local function items(t, inner)
  local count = 0
  if inner then
    for i,s in next,t do
      if type(s) == "table" then
        count = count + items(s, true)
      else
        count = count + 1
      end
    end
  else
    for i,s in next,t do
      count = count + 1
    end
  end
  return count
end

local function find(t, a, inner)
  if inner then
    for i,s in next,t do
      if type(s) == "table" then
        local x = {find(s, a, true)}
        if table.items(x) > 0 then
          return i,unpack(x)
        end
      else
        if s == a then
          return i
        end
      end
    end
  else
    for i,s in next,t do
      if s == a then
        return i
      end
    end
  end
end

local function clear(t)
  if type(t) ~= "table" then
    error("table expected, got "..type(t))
  end
  local l = {}
  for i,s in next,t do
    l[#l + 1] = i
  end
  for i,s in next,l do
    t[s] = nil
  end
end

function _G.prev(t, o)
  for i = 1, table.items(t) do
    o = next(t, o)
  end
  return o, t[o]
end

_G.table.equal = equal
_G.table.swap = swap
_G.table.copy = copy
_G.table.items = items
_G.table.find = find
_G.table.clear = clear