static void forgetTranspiledStandardFunctions(S... functions) {
  if (empty(functions))
    forgetAllTranspiledStandardFunctions();
  else
    forgetTranspiledStandardFunctions(lithashset(functions));
}

static void forgetTranspiledStandardFunctions(Iterable<S> functions) {
  Set<S> functionSet = asSet(functions);
  for (File f : listFilesWithExtension(transpiledStandardFunctions_dir(), ".functions")) {
    if (!containsOneOf(lines(loadTextFile(f)), functionSet)) continue;
    deleteFile(replaceExtension(f, ".java"));
    deleteFile(f);
  }
}