static S ocr_removeNonsenseEscapes(S s) {
  new StringBuilder buf;
  for i over s: {
    if (s.charAt(i) == '\\' && i+1 < l(s)) {
      if (!contains("[]{}_", s.charAt(i+1)))
        buf.append(s.charAt(i));
      ++i;
    }
    buf.append(s.charAt(i));
  }
  ret str(buf);
}