A recursive deepcopy implementation

deepcopy.lua

local copymember = {
    ['function'] = function(val, memo)
        local copy;
        local err = pcall(function() --handling the error is faster than getting debug info
            copy = loadstring(string.dump(val))
        end)
        if (not copy) then
            memo[val] = val
            return val
        end
        
        local info = debug.getinfo(val,'u');
        if info and info.ups and info.ups>0 then
            for i=1,i<info.ups do
                debug.setupvalue(copy, i,  debug.getupvalue(val, i))
            end
        end
        memo[val] = copy
        return copy
    end,
    ['generic'] = function(val, memo)
        return val
    end
}
setmetatable(copymember, {__call = function(self, val, memo) 
    if copymember[type(val)] then
        return copymember[type(val)](val, memo) 
    else
        return copymember['generic'](val, memo)
    end
end})

function deepcopy(orig, memo)
    memo = memo or {}
    local orig_type = type(orig)
    local copy
    if orig_type == 'table' then
        copy = {}
        memo[orig] = copy
        for orig_key, orig_value in next, orig, nil do
            copy[memo[orig_key] or deepcopy(orig_key, memo)] = memo[orig_value] or deepcopy(orig_value, memo)
        end
        setmetatable(copy, memo[getmetatable(orig)] or deepcopy(getmetatable(orig), memo))
    else -- number, string, boolean, etc
        copy = copymember(orig, memo)
    end
    return copy
end