function! text_obj#URL() abort
  if match(&runtimepath, 'vim-highlighturl') != -1
    " Note that we use https://github.com/itchyny/vim-highlighturl to get the URL pattern.
    let url_pattern = highlighturl#default_pattern()
  else
    let url_pattern = expand('<cfile>')
    " Since expand('<cfile>') also works for normal words, we need to check if
    " this is really URL using heuristics, e.g., URL length.
    if len(url_pattern) <= 10
      return
    endif
  endif

  " We need to find all possible URL on this line and their start, end idx.
  " Then find where current cursor is, and decide if cursor is on one of the
  " URLs.
  let line_text = getline('.')
  let url_infos = []

  let [_url, _idx_start, _idx_end] = matchstrpos(line_text, url_pattern)
  while _url !=# ''
    let url_infos += [[_url, _idx_start+1, _idx_end]]
    let [_url, _idx_start, _idx_end] = matchstrpos(line_text, url_pattern, _idx_end)
  endwhile

  " echo url_infos
  " If no URL is found, do nothing.
  if len(url_infos) == 0
    return
  endif

  let [start_col, end_col] = [-1, -1]
  " If URL is found, find if cursor is on it.
  let [buf_num, cur_row, cur_col] = getcurpos()[0:2]
  for url_info in url_infos
    " echo url_info
    let [_url, _idx_start, _idx_end] = url_info
    if cur_col >= _idx_start && cur_col <= _idx_end
      let start_col = _idx_start
      let end_col = _idx_end
      break
    endif
  endfor

  " Cursor is not on a URL, do nothing.
  if start_col == -1
    return
  endif

  " Now set the '< and '> mark
  call setpos("'<", [buf_num, cur_row, start_col, 0])
  call setpos("'>", [buf_num, cur_row, end_col, 0])
  normal! gv
endfunction