local _M = {}

-- this implementation is taken from
-- https://web.archive.org/web/20131225070434/http://snippets.luacode.org/snippets/Deep_Comparison_of_Two_Values_3
-- and modified for use in this project
local function deep_compare(t1, t2, ignore_mt)
  local ty1 = type(t1)
  local ty2 = type(t2)
  if ty1 ~= ty2 then return false end
  -- non-table types can be directly compared
  if ty1 ~= 'table' and ty2 ~= 'table' then return t1 == t2 end
  -- as well as tables which have the metamethod __eq
  local mt = getmetatable(t1)
  if not ignore_mt and mt and mt.__eq then return t1 == t2 end
  for k1,v1 in pairs(t1) do
    local v2 = t2[k1]
    if v2 == nil or not deep_compare(v1,v2) then return false end
  end
  for k2,v2 in pairs(t2) do
    local v1 = t1[k2]
    if v1 == nil or not deep_compare(v1,v2) then return false end
  end
  return true
end
_M.deep_compare = deep_compare

return _M