static List<String> toLinesFullTrim(String s) {
  ifdef tlft_debug
    print("tlft called on " + l(s) + " chars");
  endifdef
  new L<S> l;
  for (S line : toLines(s)) if (nempty(line = trim(line))) l.add(line);
  ret l;
}

static L<S> toLinesFullTrim(File f) {
  new L<S> l;
  for (S line : linesFromFile(f)) if (nempty(line = trim(line))) l.add(line);
  ret l;
}