static S html_linkURLs(S html, S params) {
  L<S> tok = htmlTok(html);
  for (int i = 0; i < l(tok); i += 2)
    tok.set(i, tok.get(i).replaceAll("(https?://[^\" ]+)", "<a href=\"$1\"" + params + ">$1</a>"));
  ret join(tok);
}

static S html_linkURLs(S html) {
  ret html_linkURLs(html, "");
}