return function(con)

function con.forLine(l, fn, oy)
  local x, y = 0, 0
  for j, l in utf8.codes(con.out[l]) do
    l = utf8.char(l)
    if fn then fn(l, x, y + oy) end
    if l == '\t' then x = x + 8 - (x % 8)
    elseif l == '\v' then y = y + 1
    elseif l == '\r' then x = 0
    else x = x + 1
    end
  end
  return y
end

function con.forText(fn)
  local y = 0
  for i = 1, #con.out do
    y = y + 1 + con.forLine(i, fn, y)
  end
  return y
end

end