static File transpiledStandardFunctions_file(TreeSet<S> functionSet) {
  S name = first(functionSet);
  if (isWindows()) // avoid upper/lowercase problem
    name = escapeUpperCaseWithCharacter(name, ' ');
  
  if (l(functionSet) > 1) name += "-" + md5(joinWithSpace(dropFirst(functionSet)));
  name += ".java";
  ret newFile(javaxCachesDir(), "Transpiled Standard Functions", name);
}