table allocation management for Lua

init.lua

local free, free_l = {}, 0
local _print = print


local function dealloc( t )
  free_l = free_l + 1
  free[ free_l ] = t
  return true
end

local mt = { __metatable = false, __gc = dealloc }


local function alloc()
  if free_l > 0 then
    free_l = free_l -1
    return free[ free_l + 1 ]
  else
    return setmetatable( {}, mt )
  end
end


local function purge( t )
  for k in next, t do
    rawset( t, k, nil )
  end
end


return {
  alloc = alloc,
  purge = purge,
}