grab("#137")
get("#135")

function clockplus(clock, plus)
  local h, m = unpack(split(clock, ":"))
  log(h, ":", m)
  if h == nil then error("bad format") end
  h=tonumber(h)
  m=tonumber(m)
  m = m+plus
  if m>=60 then m=m-60 h=h+1 end
  if h>=24 then h=0 end
  
  -- have to use 2 lines because of LuaJ error localisation bug
  local result = clockformat(h, m)
  return result
end