local len = utf8.len(s)
  local offset = Text.offset(s, math.min(pos+1, len+1))
  local s_before = s:sub(1, offset-1)
--?   print('^'..s_before..'$')

  local offset = Text.offset(s, math.min(pos+1, #s+1))

  local len = utf8.len(s)
  local offset = Text.offset(s, math.min(pos+1, len+1))