function split(s, delim)
if type(delim) ~= "string" or string.len(delim) = 0 then
return
end
local start = 1
local t = {}
while true do
local pos = string.find (s, delim, start, true) -- plain find
if not pos then
break
end
table.insert (t, string.sub (s, start, pos - 1))
start = pos + string.len (delim)
end
table.insert (t, string.sub (s, start))
return t
end